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Ask Meredith: Horticultural Oils

September 23, 2013

mereDear Meredith,

Here I sit browsing the June/July issue of The Appalachian Voice and came across an interview with two folks from the OGS. In it there is a recipe for garlic soap spray, supposedly the executive director’s favorite. One of the ingredients is mineral oil. The Internet defines mineral oil as “a liquid by-product of the distillation of petroleum to produce gasoline and other petroleum-based products from crude oil.” How is that organic? I know that some folks think this stuff is the best thing to use on their wood and metal kitchenware. I think the idea of eating petroleum sounds disgusting and potentially hazardous. What do you think?

Matthew Hester

Dear Matthew,

This is an excellent question, and not one with an easy answer. You are correct that mineral oils, which are components of horticultural oils, are byproducts of petroleum processing. As coffee-stirrers are to the lumber industry, so are mineral oils to the petroleum industry. They are colorless, odorless oils that remain after refinement of crude oil, so are produced in huge quantities, and carry a relatively low value. As a result, the market for mineral oil has been obviously bolstered by an industry interested in maximizing a waste stream to the fullest extent. Aha! This kind of thing is a kingdom for my enthusiastic skepticism. Let’s dig a little bit deeper, shall we?

Petroleum-based oils have been used in agriculture since the beginning of the industrial era, mostly in the form of “dormant oils” then, which are extremely viscous, relatively un-refined mineral oils used on woody plants. “Horticultural oil” or “Hort Oil” is an umbrella term used to describe mixtures of a mineral oil and a detergent, for use on plants to deter pest insects, molds, and mildews. What differentiates the various horticultural oils has to do with the amount of detergent used in combination with the oil, any additional ingredients (such as those in my DIY garlic soap recipe), and also the degree to which the mineral oil component has undergone refinement. In general, the more refined the oil, the safer it is for use.

Things to look for when determining the grade of mineral oil in your hort oil product are ratings for sulfur content, viscosity, and evaporation rate. Sulfur content is expressed as a UR rating (“unsulfonated residue”), and the higher the UR rating, the lower the sulfur content. Since sulfur can be toxic to plants, you want to look for a hort oil with a high UR rating. Most hort oils already have UR ratings in the 90s, anyway, since they are intended for plant uses.

Viscosity of oils is measured by the time it takes the oil in question to flow through a test ring. For example, an oil that takes 60 seconds to flow through the test ring is rated a 6E oil. An oil that flows through in 80 seconds is rated a 8E oil. The lighter the oil, the more refined it is. Evaporation rate is closely tied to viscosity. The lighter the oil, the faster it evaporates.

Mineral oils are a mix of hydrocarbons, mainly alkanes (paraffins) and alicyclic hydrocarbons (naphthenes). Both of these hydrocarbons have a relatively low toxicity, and have been scientifically proven to show no significant toxicity upon prolonged exposure to their vapors.

twomoleculesNow, many people freak out when they hear the word “hydrocarbon,” simply because people who care about this stuff know that hydrocarbons=fuel sources, and thusly must be something we shouldn’t use lightly. This is mostly true, but lots of people don’t realize that hydrocarbons are naturally occurring. Methane is a perfect example. What is freaky about hydrocarbons is their ability to bond to themselves, which can sometimes give you dangerous molecules like benzene. However, simple, straight-chain hydrocarbons (paraffins), like the ones you’ll find in very light hort oils are not susceptible to this self-bonding, or catenation. The presence of aromatic atom rings in hydrocarbon molecules is where toxicity reaches significant levels. The simplest aromatic ring is the benzene ring, and benzene is classified as a known carcinogen. Knowing that aromatic hyrdocarbons only get more complex from there, and that they don’t occur in mineral oils, we can probably leave that topic alone, now.

Please don’t confuse paraffins with parabens, either. They are really different. Paraffins are pretty stable and have low to no toxicity. Parabens are a straight no-no. That’s another topic for another time perhaps, along with a deeper look at benzene.

Another word that makes people stutter is “naphthene”, which is a hydrocarbon found in some hort oils. Folks are likely to confuse naphthene with naphthalene, aka “mothballs”, which are nasty little solids you should avoid like the plague (read: aromatic hydrocarbon). However, napthene is an “alicyclic hydrocarbon”. Alicyclic means that is is not aromatic. Just because a hort oil contains mineral oil, doesn’t necessarily mean it contains a bunch of naphthene. Some oils are higher in naphthene than others, and the more refined the oil, the tinier the quanitites of any hydrocarbon, anyway.

OK, now that your head is full of rings and carbon atoms, lets talk about how hort oils actually work. Basically, they smother insects, or coat leaf surfaces to prevent mold and mildew spores from landing on the leaf. Most pesticides, in contrast, interfere with biochemical processes in the insect’s body. A chemical that can disrupt the body chemistry of an insect can also be harmful to humans. An oil that harms by suffocating the insect is decidedly less harmful to you as a gardener. That said, I probably shouldn’t go into the use of mineral oils in cosmetics and baby products. I’ll just briefly state that it is a BAD IDEA. Judicious use of mineral oil in the garden, meaning light oils applied safely, and during the proper season, pose relatively small risk to you.

Light oils will most definitely evaporate before you harvest from the plant, and since the vapors are the concern, here, anyway, if you are worried at all you should be worried about proper application, not residue. This is why mineral oils are approved for organic use, described as “synthetic oils with a boiling point between 415-445 degrees F”. They are classified as considered “narrow range” controls and are allowed with restrictions on leaf surfaces.

Know that hort oils can kill beneficial mites, because they are too slow to move out of the way and can be suffocated. The good news is that most beneficial insects fly out of the way when they detect hort oils, and are usually unharmed. If you are super anti, consider subbing neem oil (caution: toxic to honeybees) in your homemade spray, or even castor oil. The resulting concoction will be less effective, but similar in its mechanism. In the case of Neem, we also see how different treatments pose different risks, and you really can’t totally win when you’re trying to encourage nature through organic gardening, while simultaneously trying to control her more unfortunate processes (like plant diseases and insect pests).

Bottom line: Many hort oils contain only tiny amounts of mineral oil anyway, and those component mineral oils contain tiny amounts of non-aromatic hydrocarbons to be concerned with. Main points:

  • Look for lighter, more refined oils, and search the labels for UR ratings, and viscosity grades.
  • Use safety gear when spraying hort oils, and use them only as directed.
  • Note that some hort oils are intended for use during plants’ active growth periods (summer, mostly), and others are intended for use during the dormant season.
  • DO be skeptical about mineral oils in body care and especially baby products, and avoid them.
  • Consider creating your own oil-soap combinations, and try subbing in different, naturally occurring oils like neem or castor. Record your results for future use.

I hope this helps!



Ask Tom: Farmer Ergonomics

September 23, 2013

ask-tom-pictureDear Tom –

With the late spring and incessant rain in June, this season was very stressful but making things worse was back pain on and off all season. Any suggestions?

Aching Andy in Tuxedo

Dear Andy –

You are not alone. Farming is the occupation most associated with disability in females and second most in males. The severity of the disability was second highest for women and fifth highest for men. (Leigh and Fries, 1992)

Solving back pain or any other work-related pain may involve a three part strategy:

  • short term cures,
  • injury prevention by personal preparation, and
  • injury prevention by improving your workplace.


The first step may be body awareness. Even in the rush of harvest, I try to be aware of twinges caused by overworked muscles. Pushing through the pain rarely works out for me. Consider changing postures or positions at the first sign of problems. We hand transplant most of our crops so I have six or eight different postures for transplanting – bending, kneeling, straddling the bed, to the left, to the right, etc. Heading off the problem usually works for me.

stretchingThe next step for me is to remember at the end of the day when my muscles have been stressed. Farming is often an athletic activity and yet few of us warm up before or stretch afterwards. Stretching by Bob Anderson is a great resource. Remembering to stretch before work may be unlikely but I try to always do it at the end of the day. While not very “natural,” Advil often works for me when stretching is not enough.

Physicians seem to lean toward rest and muscle relaxants which work for some people. The sheet of exercises that should go with the prescription may be the most valuable product from that visit to the doctor but those handouts are available on line for free (search on back pain exercises).

While the scientists among us may be skeptical, I found the homeopathic remedy Rhus tox on one occasion when I was stuck in bed with low back pain. (Editor’s note: Consult your own health advisor before following any suggestions in this article.) Massage is effective for many. Both tailgate markets that we attend have massage therapists that offer their services from time to time.


I am impressed with how quickly winter stretching and strengthening exercises work to prepare me for the coming season. This PowerPoint has a good section on strengthening and stretching back muscles. Similar programs exist for ankles, wrists, etc.


Perhaps the best solution is to prevent ergonomic problems in the first place. Consider, for example, smaller harvest containers which are easier to move around. Or a wheel hoe to replace a conventional hoe. The Healthy Farmers, Healthy Profits site has dozens of ergonomic solutions to a variety of small farm problems (click vegetable at the bottom). Their harvest cart looks interesting.


Another publication, Simple Solutions: Ergonomics for Farm Workers, overlaps the Health Profits site, but it also puts some of their tools in context and offers guidelines for designing workspaces such as sorting tables.

reach length

Winter is coming so now may be a good time to look at your farm operations that are a pain in the back (or other places) and streamline your operations for next year.

— Tom

Ask Tom © 2013 Tom Elmore & Organic Growers School

Farmers: Got a question for Tom? Email it to us at

Ask Ruth: Preventing Tomato Blight & Resistant Varieties

September 23, 2013

ask-ruth-pictureHi Ruth,

After this wet summer, I’m wondering if any varieties of tomatoes showed any resistance to the blight (early or late). I grew Opalkas, Amish paste, and Juliets for canning; Cherokee pink, Brandywine Black, Eva Purple Ball, and Early Girl for eating; and Sungolds and Black Cherokees for cherry tomatoes. Here at the end of August I picked a few cherry tomatoes, but all others are gone. Juliets lasted the longest. So what to do next year???

I never grow tomatoes in the same place or where potatoes were. I’ve even tried growing tomatoes outside of the garden in new ground. I use fresh compost every year and I don’t till. I put landscape cloth beside my plants to reduce weeding and prevent soil splash. I’ve tried Serenade alternating with copper to help prevent blight. What else can I do?

Madison County

Hello Pat,
You are an excellent and very experienced gardener, and it sounds like you are already extremely pro-active regarding tomato blight prevention. Like most Western North Carolina gardeners, you have been facing the devastation of tomato blight for years on end, and it is a super-frustrating disease. I had never experienced tomato bight when I moved here 22 years ago. During my first gardening year in the mountains, my tomatoes were almost six feet tall and beautiful at the beginning of August. When I returned from a vacation two weeks later, my tomatoes looked like they had been sprayed with an herbicide (they were mostly a dead brown color). It was my first shocking encounter with tomato blight. Ouch!

Tomato blight is merciless. Don’t take it personally. I talked to a few organic farmers at the Montford Farmers Market and their conclusions match my own conclusions. With tomato blight in WNC, it is not a question of if you will get blight, but more a question of when you will get it. We talked various strategies for staving it off (some below). Not very encouraging is it?


Early blight of tomato, Alternaria solani, is a fungal pathogen that appears as concentric spots on the foliage and can eventually rot out the stem. Prevention is the key.

Source: WNC Vegetables & Small Fruit Newsletter

Source: WNC Vegetables & Small Fruit Newsletter

Late blight of tomato, Phytophthora infestans, is caused by a fungus-like pathogen, the same one that caused the Irish potato famine in the 1840’s. This serious disease can be spread by infected transplants, and by volunteer tomatoes or potatoes and certain related weeds. The airborne spores can travel 10+ miles, and spread via wind and rain. This summer’s weather was especially favorable with lots of rain and cool, overcast days. The first signs of late blight are irregularly shaped, water-soaked lesions that usually have a lighter colored ring around them. In bad years, a crop can be destroyed in less than two to three weeks. Prevention is the key.

Source: Growing Small Farms

Source: Growing Small Farms


Choosing Tomato Plants: Buy healthy transplants and check transplants for signs of blight before you purchase them.

Choose Fast Growing Tomatoes: Choose plants that mature quickly, like Early Girl* (harvest tomatoes before blight arrives). Or choose plants that will grow quickly – mostly hybrids, any fast-growing tomato, or grafted tomatoes – so that they can outrun the blight (the top tier will be producing while the bottom tier is blighty). *This strategy works some years, but this year both Pat and I had bad luck with Early Girl.

Choose Blight-resistant Tomatoes: Blight-resistant does not mean blight-proof, it means that blight is slowed down so you will get a longer harvest. Resistant tomatoes are bred to resist particular strains of blight. If that blight strain mutates or a new strain shows up, we’re back to the drawing board. Some suggestions by locals were:

  • Mountain Magic F1 Hybrid – Indeterminate, small red tomato (larger than a cherry, smaller than a plum). Vanessa Campbell says it is one of their favorites; it tastes great and is good for everything except slicing for sandwiches. A Randy Gardener/NC State tomato.
  • Plum Regal F1 Hybrid – Determinate, red plum tomato. Another Randy Gardener/NC State tomato.
  • Matt’s Wild Cherry – Heirloom, Indeterminate. Red fruit. Was listed in multiple places. EB resistant, moderate LB resistance.
  • Iron Lady F1 Hybrid – Vanessa had good luck with Iron Lady. My Iron Lady got blight (I did not spray) but it produced a lot of tomatoes. I thought they were good, but one of my friends thought they were mealy.
  • NCSU 144 – Tom Elmore had good luck with this pink tomato from NC State. I planted it last year and it did seem blight resistant, but was not very productive for me.
  • Defiant F1 Hybrid– Determinate, Mid-sized red fruit. Harry Hamil’s friend had good luck with this and Johnny’s catalog devoted an entire page to this tomato. I would love to try it.
  • Big Beef F1 Hybrid – Large red fruit, Indeterminate, Jenn Cloke has good luck with this tomato in both wet and dry years (but she adds that she uses “nuclear amounts of copper”).
  • Legend F1 Hybrid – Determinate, large red round fruit, early, OSU
  • Mountain Merit F1 Hybrid– determinate, a large-fruited red variety with resistance to some strains of late blight. A Randy Gardener/ NC State tomato.

Scroll to page 4 of this link for more blight-resistant tomato variety ideas. Unfortunately Pat, some of these listed varieties didn’t work well for you this year, like Juliet.

Fungicides for Early & Late Blight: Approaches for early and late light are very similar. Basically, especially for organic gardeners, both early and late blight must be prevented, as it cannot be controlled once you already have blight. This means spraying weekly or more often with an organic fungicide, and it is a good idea to start your spray regime at planting time. You need to spray often enough to protect new foliage, and Dr. Jeanine Davis recommends re-spraying after a rain. Fungicides should thoroughly coat the plant on all sides of the leaves and it is best sprayed early in the morning when the plant is wet from dew anyway. I like using a sprayer with a wand so you can easily reach the undersides of leaves and the insides of the plant. Most copper formulations are considered dangerous so – with any and all pesticides – always read and follow all safety, re-entry, safe harvest, and other instructions.

Full Sun Farm alternates between the fungicides Oxidate and Actinovate, but they did not spray this year because it seemed hopeless with all the rain. Next year they may add copper to their spray rotation. The farm manager for Johnny’s Selected Seeds names Oxidate as his favorite tool to use for late blight.

Jeanine Davis recommends spraying every 5 days alternating copper and Serenade (Bacillus subtilis), Sonata (Bacillus pumilus), or Sporatec (mostly herbal oils). She has experimented with using Serenade + copper for one spray and then Sporatec + Neem in the next spray but now is unsure about combining copper with Serenade in the same spray because there is some controversial about whether the copper inactivates the Serenade or not. Read more here.

Another popular regime is alternating Senenade (Bacillus subtillus) with copper. Regime:

  • Week One – spray Serenade;
  • Week Two – spray Serenade;
  • Week Three – spray copper;
  • Repeat sequence until frost.

Firefly Farm grows a number of heirloom tomatoes under cover. They use Serenade and they also spray with hydrolyzed fish and liquid seaweed. Scott does not use copper.

Copper is often considered the most effective fungicide for blight, however copper is a heavy metal that can accumulate in the soil. There are some concerns about copper’s effects on human health and wildlife including earthworms and bees; it is highly toxic to fish, and has even been banned in the Netherlands and Denmark. According to eXtension, “As required by the certification process, farmers must use all available alternative practices to manage late blight, and describe these in the Organic System Plan, before deciding to apply a copper product.” Certified growers should consult with their certifier before applying copper. Read more about copper here.

CULTURAL PRACTICES to Help Tomatoes Resist Blight

  • Mulch – to keep the pathogen from bouncing up from the soil and on to the plant.
  • Remove Volunteers – Immediately remove volunteer tomatoes and volunteer potatoes for best blight prevention.
  • Air circulation – Plant tomatoes in an area that has good air circulations with consideration given to prevailing winds. Keep area weed-free to encourage good air circulation. Sucker tomato plants so they are less bushy and will allow more air to circulate.
  • Water – Water in early morning at the base of the plants (not with a sprinkler), or use drip tape. Keep the foliage dry. Tomatoes require 1” of water per week. Don’t let your plants become drought-stressed.
  • Fertilize – Apply adequate amounts of compost or fertilizer to keep your plants growing nicely, but don’t over-fertilize as that can cause other problems. You want enough new growth that the tomato plant stays ahead of the blight.
  • Prevent Spread of Disease – Don’t work your plants when they are wet as this will quickly spread the disease. Harvest at the end of the day when foliage is dry. Keep hands and tools clean. Work blighty plants last, so you don’t contaminate good plants. Scout for blight every few days.
  • Remove Blighty Material – Remove blighty leaves from the plant, being careful not to touch other parts of the plant. Don’t compost blighty tomatoes, leaves, or vines. These should be bagged and removed from the property or deeply buried. Clean up well in fall.
  • Rotate Your Crops – Don’t plant nightshades (tomatoes, potatoes, peppers, eggplants, etc.) in the same area next year.
  • Save Your Best Seed – If you plant heirloom tomatoes, save the seeds from the tomatoes that show the most blight resistance. For the last ten years, Scott Paquin has been selecting seed from his Cherokee Purple tomato plants based on their most blight resistance traits. Don’t bother saving seed from hybrid tomato plants since they will not be true to type.
  • Keep Your Plants Healthy – so they are less susceptible to disease.
  • Store Blighted Fruit Separately From Good Fruit – The pathogen can move from the blighty fruit into the good fruit. Blight spots on tomatoes are darkish-colored and have an unpleasant odor. You can cut the bad spots out and still eat the tomato – up to a point.


hightunnelMany local farmers raise their tomatoes in a high tunnel that has been designed for summer ventilation with roll-up sides and good ventilation capability on each end. This keeps the plants dry, and dry plants are way less susceptible to blight. Drip tape is installed for irrigation right at the base of the plant. In his tunnel, Scott Paquin has good luck with Marglobe and Cherokee Purple, both heirlooms.

Jeff Ashton described a contraption that Dr. John Wilson uses to keep his tomato plants dry. He installs a tall 2 x 2” stake (about 8’ tall) in the middle right next to the tomato. He adds 4 shorter poles around the outside of the tomato and covers the whole business with greenhouse plastic – essentially creating a tent to keep the tomato dry. The plastic should not touch the plant. He probably pads the top of the poles a little to keep the plastic from tearing. This is a bit funkier than a high tunnel, but it also requires a lot less investment. You will need to water at the base of the tomato plant.

Tom Elmore suggested another inexpensive idea for keeping your plants dry. Plant your tomato in full sun on the south side of the house under the cover of the roof eave. Apply fungicidal sprays (Tom suggests copper), and water the tomato plant at the ground level. I think tomato blight will always be a challenge in the southern Appalachians, but hopefully this was of some help to you Pat – and I hope you have better luck with your tomatoes next year.

Special thanks to Vanessa Campbell/Full Sun Farm, Christina Carter /Ten Mile Farm, Jenn Cloke, Tom Elmore/Thatchmore Farm, Harry Hamil, Scott Paquin/Firefly Farm, and Pete Shriner/ Blue Ribbon Farm for their thoughts on blight/blight-resistant tomatoes.

Thanks for writing and happy fall gardening,

Ask Ruth © 2013 Ruth Gonzalez & Organic Growers School

Gardeners: Got a question for Ruth? Email it to us at

Ask Ruth January 2013: Starting Your Own Transplants from Seed

January 27, 2013

ask-ruth-pictureDear Ruth,

I want to start some of my own transplants this year. Do you have any seed starting tips?


Ella in Marshall, NC



Dear Ella,

This time of year invites dreaming about the magic of seeds sprouting out of the soil. Did you know that the smell of earth actually lifts your spirits? (I am not surprised! Are you?) This month many of us have been gardening from our sofas…courtesy of our favorite seed catalogs, but it sounds like you are ready to get to your hands in the dirt and actually plant. Bravo!

Here are a few seed starting hints that may help your success:

seed pack info 006Make a Seed Planting Schedule

Base your seed planting date on the earliest date when the baby plant can be transplanted outside, along with the estimated harvest date. Look on the seed pack or in the seed catalogue to determine the number of days to maturity and count backwards to establish the ideal date to get your seedlings started.

In WNC, some cool weather crops can be set out in late February with protection. Many more can be planted in March. In the mountains, you will want to wait to set out heat-loving transplants, like tomatoes and peppers, until after Mothers Day (May 10 to 15).

Here is a NC Cooperative Extension Planting Guide. Please note that these dates are for North Carolina as a whole – in Western NC you must DELAY planting 10 to 20 days in spring.

Use Fresh, Quality Organic Seed

Whether you buy your seed through a catalog, a local garden center, an ag supply store, or a local seed company…buy reputable seed. Purchasing Certified Organic seed guarantees that the seeds you buy have been raised using organic farming methods which benefit the environment and benefit the health of farm families and farmworkers. Planting Certified Organic seeds also ensures that the seed contains NO GMO’s (Genetically Modified Organisms).

Planting seeds and growing your own transplants allows you to choose unusual seed varieties that you may not find for sale anywhere.

Use a Seed Germinating Potting Mix

These mixes have a very fine texture with minimal bark added, and have been especially formulated for starting seeds. McEnroe Lite is not a germinating mix, but it works well too.

Follow the Instructions…Dibber - planting seeds 1-25-2013 001

on the seed packet or in your favorite garden book regarding how deep to plant your seed.

Each seed has its own requirements. Some seeds don’t even need to be covered with soil (like lettuce) and may require light to germinate, so check before planting. Use a pencil as a dibble and mark common increments with a permanent marker. In the center of each cell in your flat – poke a hole in the soil to the correct planting depth and sow your seeds.

ID and Date Your Plantingsplanting seeds 1-25-2013 004

Broccoli and cabbage look a lot alike. Be sure to mark each planting with the cultivar name so you know which flat has the broccoli. Specify the cultivar name if you are planting more than one variety. It is doubtful you will remember later on. Believe me…most gardeners have made that mistake at least once…and probably multiple times. You may want to note expected days to germination. Also date each planting, so that if those particular seeds don’t come up within the expected timeframe you will know what needs to be replanted. Example: ‘Packman’ Broccoli 1-31-13

Bottom-Soak your Flat…

in water laced with liquid kelp before you plant the seeds. Find a plastic tub a bit bigger than your flat. Add water to the tub along with some liquid kelp (kelp enhances germination rates). Float your soil-filled flat in the tub and let it soak until the soil is wet all the way to the top. Dibble your holes, then sow your seed, and cover seeds with soil if needed. Moisten any additional soil – being careful not to blast the seeds out of their positions. Because wet soil is heavy, you will need to set the wet cells directly into a flat so that transporting them is manageable. Bottom soaking is a little extra work that pays off. This step is not a must, but it works very well!

Germination Station and Heat MatHeat-Mats really do increase germination!

Heat-mats warm the soil which encourages the seeds to sprout. Fancier heat-mats have adjustable thermostats that can target the ideal soil temperature for sprouting a particular seed. Though it is nice to have the option to set the mat’s temperature, the less expensive mats work really well too, and usually accommodate one flat. Heat-mats are especially effective with heat-loving plants like tomatoes, but will speed germination in cooler season plants. Lettuce will germinate in soil as cool as 40 degrees, so don’t waste your heat-mat space on lettuce.

Use Grow Lights

As soon as you see green leaves appearing, immediately turn on your grow lights. Plants can stretch in just a few hours (and then get floppy). Position the grow light(s) close to the soil surface and be ready to adjust the lights on a daily basis. Provide an adequate number of grow lights for the amount of seedlings you are starting. The light(s) should be close enough to keep the seedlings from stretching and far enough away from the plants to prevent burning. A distance of about 2” from the leaves works well.

If you don’t have a grow light, place your plants by your brightest window, rotate them daily, and be sure to take them outside on mild days.

Water is Essential

Provide adequate water. Get it just right…like Goldilocks. Too much water can cause root rot and d e a t h. Too little water and the plant may shrivel and d I e. Gauge moisture levels by pressing your finger into the soil. If it feels wet, wait to water and check again later. Water if the soil is dry-ish, but avoid letting the soil get bone dry. A mister bottle is helpful when the seedlings are delicate.


Garden Centers/Ag Supply Stores usually have mini-greenhouses for sale. These are plastic domes that fit the seedling flats exactly and help retain moisture in the seedling flat. Some domes measure about 2” high and other domes are much taller to be able to accommodate older, taller seedlings.

Harden Off Your Transplants

On mild days, take your plants outside to experience the real world. This will toughen them up and get them ready for transplanting. Mild breezes make plant stems stouter. Some people even use fans to create a breeze and accomplish this artificially. Bring your plants back inside at nighttime or when you get home from work. It is a good idea to leave them out all night for a few days prior to transplanting outdoors into your garden or containers. Shoot for planting during a mild spell of weather, in the evening, or just prior to a nice rain (all three of these would be ideal!).

Oh…and more Water

Remember to water your plants well at transplanting time (I like to water in my plants with a liquid fish/seaweed blend mixed with warm water). Also, water your transplants regularly once they are planted (they require 1” of water per week).

Ella, spring is right around the corner and you are getting a head start. Early spring salads and veggies are not only tasty, they are packed with the good-for-you nutrients our bodies crave this time of year. Your baby transplants will turn into delicious suppers in no time. Yum!

Happy Gardening,


Gardeners: Got a question for Ruth? Email it to us at

Ruth Gonzalez is a former market farmer, gardener, local food advocate, and founder of the Tailgate Market Fan Club where she blogs at In her job at Reems Creek Nursery, Ruth offers advice on all sorts of gardening questions, and benefits daily from the wisdom of local gardeners.

Ask Ruth © 2013 Ruth Gonzalez & Organic Growers School

Ask Tom January 2013: Spotted Wing Drosphilia

January 25, 2013

ask-tom-pictureTom –

 I have heard talk about a new fruit fly that is a problem for berry growers. What organic practices are available to manage that pest?

— Perplexed in Lickskillet

Dear Perplexed –

It is called the spotted wing drosophila (SWD) and is similar to our traditional fruit flies, which are attracted to overripe fruit. An important difference is that the SWD will consume and is able to lay its eggs in sound and ripe fruit. They are able to do this because of the females’ large, blade-like ovipositor (egg-laying device). Berries can look fine at harvest but may contain larvae (aka maggots) when the customer gets them home. Alternatively, SWD can hatch in the clamshell container. Often they fly when berries are placed in the refrigerator because the maggots will leave the fruit in search of warmer temperatures. As you might expect neither of these outcomes is good for return sales.


This new pest was first seen in NC about three years ago. Research is underway on management strategies but some recommendations are emerging that organic growers can use to minimize the damage on their farm.

Which Fruit are at Risk?

In the literature the fruit most often mentioned are raspberries, blackberries, strawberries, blueberries, cherries, plums, peaches, and occasionally on damaged tomatoes. In North Carolina, SWD has been found in raspberries, blackberries, strawberries and blueberries. Larger fruit can be affected but most often those infestations have been associated with damaged fruit.

How do we monitor and identify SWD?

SWDpp_clip_image002_0000Apple cider vinegar lure traps are most often recommended. Traps are used only for monitoring the timing of the appearance of SWD and are not effective as a management strategy. Here are plans for a simple trap using plastic drink cups.

Some believe a yeast solution is more effective. This link offers a recipe at the bottom.

Hundreds of species of fruit fly exist, so we need to know which ones are SWD. There are two distinguishing features of the SWD for identification. The first is the male SWD have two distinctive spots on the end of each wing. The second is the female SWD’s large, blade-like ovipositor. This ID card seems fairly useful to me.

The photo above might also be helpful. With a hand lens or for those with particularly good near vision, the large red eyes are a tipoff but look for the other features too until you are accustomed to telling these tiny critters apart.

What cultural practices help?

I consulted local berry grower Walter Harrill and NCSU Extension Agent Sue Colucci and here are their suggestions plus other NCSU suggestions from Dr. Hannah Burrack:

  1. Use vinegar traps and monitor for the arrival of SWD in order to guide spray programs.
  2. Harvest early and often even to the point of picking some slightly unripe fruit.
  3. Collect cull fruit and disinfect them with extreme heat or cold such as sealed plastic bags left in the bright sunshine for several days or placed in the freezer. Burying and composting are not reliable ways to destroy eggs and larvae.
  4. Keep plants and fields dry by using drip irrigation and keeping leaks maintained. Avoid any puddles or standing water in the field because SWD seem to be attracted to these areas.
  5. Consider value-added crops as an alternate to marketing fresh fruit and freeze them promptly after harvests to keep any SWD eggs from developing.
  6. Change crops. (This comment from Walt was in jest but worth considering,)

Bug zappers do not appear to work and no pheromone mating disruption systems have been developed at this time.

Sue emphasizes that monitoring is very important. We tend to trap SWD all year, yet we have not seen problems in early crops- like strawberries. Growers should set traps in all potential crops.

What organic sprays are effective?

Entrust is the organic control that is reported to be most effective. Even prohibited material controls are starting to show reduced effect so an integrated approach is probably important. The life cycle for fruit flies is so short that frequent sprays may be needed. Some growers report problems with the appearance of the fruit after spraying. NCSU spray recommendations are on the table at this link.

That table rates organic controls as follows:

Control Material


Spinosad (Entrust)


Pyrethrin (Pyganic)


Stylet Oil


Insecticidal soap


None is rated as excellent in the NCSU analysis.

The Washington State recommendation for Entrust rates and rotation timing on cherries








2 (Pyganic )




2.5 (Pyganic )

total oz


Pyganic is added to avoid exceeding the label limits for Entrust. Check this source for more detail. Regarding the amount of Entrust to use WSU offers that “while the 2(ee) label for Entrust give 1.25 oz/acre as the lowest rate, preliminary bioassay data indicates a distinct drop in efficacy between 2 and 1 oz (2 and 3 oz both provided 100% mortality of females, whereas 1 oz caused only 50%).”

California Extension Recommendation for Organic Growers

“Contact your certifiers early in the year to make sure they will approve the use of spinosad (Entrust), pyrethrin (Pyganic 5.0) and/or azadirachtin (Aza-Direct) if SWD begins to cause damage. Pyganic 5.0 contains pyrethrins-a botanical insecticide derived from chrysanthemums. Entrust is the organic formulation of spinosad. Aza-Direct is azadirachtin which is a type of Neem product and used as a botanical antifeedant, repellant and insect growth regulator. Generally the organically approved products are not as effective as the other (non-organic) products previously mentioned, but can suppress fly populations and are important tools for organic producers. Recent studies in control of SWD in organic raspberries by Mark Bolda (UCCE Santa Cruz) showed differences in the number of SWD larvae in fruit treated with Pyganic 5.0 @ 18 oz. and Entrust @ 2 oz. compared to an untreated control. Bolda also looked at Pyganic 5.0 @ 18 oz. combined with Aza-Direct @ 2 pt. and this treatment provided similar control as that of the Pyganic 5.0 @ 18oz. alone. Pyganic 5.0 @ 9 oz. did not provide control in Bolda’s study. Interestingly, in Bolda’s work, treatment differences can not be seen when measuring adult fly populations (he uses a D-vac to vacuum up adult flies)-only when measuring maggots inside fruit. Other organic products such as GF-120 and a variety of oils are reportedly not very effective. It is also just as important to remember that Entrust and other organic products, as with conventional materials, should not be over-used in efforts to prevent resistance development. Entrust has a pre-harvest interval of three days in blueberries. Check the labels for PHI for other materials in other crops.” Source:

Cornell Recommendations including Entrust and Pyganic are at:

As if we needed one more pest to manage mid-season. SWD is a recently arrived pest and control research is underway. Stay in touch with Extension for the latest developments.

Good luck and happy spraying.

— Tom

Other Resources:

NCSU Fact Sheets:

Map of counties affected so far:

Hey, Farmers! Got a question for Tom?

Email it to

CRAFT Tour: Balsam Gardens and Pastured Poultry

November 19, 2012


It was a rainy Saturday afternoonon September 29th for the CRAFT tour at Balsam Gardens, but that didn’t stop our dedicated CRAFT members from making the trip, nor did it detract from Steven Baltram’s  and Becca Nestler’s ability to provide a rich and insightful look into Raising Poultry on their small scale farm. Huge thanks to both of them for inviting us onto their farm and into their home for a truly personal and informative farm tour.

Balsam Gardens began when Becca and Steven moved to their property in Sylva in 2007. They took their first step into farming by setting up a stand at the nearby Sylva Tailgate Market in 2008. As the farm has grown they have moved into selling their produce and meats at the Waynesville Farmer’s Market, to some restaurants, a few distributors, and in a 30 family CSA. This will be the third season that Steven and Becca have worked for the farm full-time during the summer, but Steven will continue picking up carpentry work in the winters. After sticking to vegetables the first few years, they began to add animals three years ago and started with 3 batches of 50 broilers and 2 pigs. This year they have raised 30 pigs, close to 1300 broilers, 200 laying hens, and 200 turkeys.

ImageFollowing a brief introduction to the history of Balsam Gardens, we stopped to see the poultry processing equipment that Steven set up to demonstrate how they process the chickens and turkeys on the farm. Thanks to a grant they received from the Western North Carolina Agricultural Options program they were able to purchase killing cones, a scalder, and plucker machine. The killing cones are a circle of inverted metal cones where the bird processing begins. A bird is placed upside down in each cone with its head sticking out the bottom (there are two different size cones for chickens and turkeys). Then, they cut the main vein in the bird’s neck with a scalpel, and the blood drains out into collectors underneath the cones. This way instead of buying blood meal as a nitrogen addendum to their fields they’re sourcing it right on their farm!

Once the bird has died and the blood has drained, the carcass is moved to the scalder where it is dipped in water at 145°F for about 45 seconds. Steven and Becca’s propane scalder is large enough to scald 4 chickens at a time, and has a thermostat that regulates the temperature so it stays a consistent 145°F. Steven explained that if the water is too hot, the skin will tear when plucked but if it’s not hot enough the feathers will not come out as easily backing up the processing line.


The next stop for the carcass is the plucker which looks like half a barrel with a rotating floor. The sides are covered with rubber finger-like attachments that catch and pull out the feathers as the birds tumble around inside. It only takes 30 seconds to de-feather 4 chickens in this thing. Removing feathers by hand is the most time consuming part of processing chickens, which is why Steven recommends that of these three pieces of equipment the plucker is the most vital purchase. The killing cones and scalder while still necessary can be rigged with a little creative thinking. But if you’re going to process large batches of chickens several times a year, a plucker would be a wise investment.

One or two people are able to run these three steps of the process. Next to the trio of equipment they set up two stainless steel folding tables. Here, one person preens the bird, or cleans off its remaining feathers, pulls off the head and cuts off the feet. The bird carcass is sent down the table where it is eviscerated, or all the organs are removed. Finally, the bird is rinsed, shrink bagged and labeled for sale. The chickens are then sold at the tailgate markets and through the meat share in the CSA, while the turkeys are pre-ordered by customers and picked up in time for Thanksgiving.

ImageAfter walking through their poultry processing method, we visited the laying hens. Steven explained that he parked the layers on a plot where his crop of beets was overtaken by crabgrass. At Balsam Gardens they purchase their laying hens, a Red Sex Link breed, as pullets for $6 because Steven found it’s cheaper than the $11 it takes to raise a chick to laying age. For their broilers or meat chickens they raise the traditional Cornish Rock Cross, and Broad Breasted White turkeys.

When asked how they keep their poultry healthy Steven explained that getting a nutrient balanced feed that has the right protein percentage is essential. They are able to have their grain feed custom mixed at a local mill in Sylva. “There is nothing higher risk than raising turkeys,” Steven told us, due to their disease susceptibility and predation when they’re young. When doing chores they will typically visit the turkeys first to cut down on carrying diseases, like Blackhead, that might be present in the chicken flocks to the turkeys. Blackhead is a protozoon that will kill all of your turkeys and persist in the field for up to 4 years once it is present.

ImageThen, we hopped in a few cars and traveled 7 miles down the road to a field Becca and Steven rent from Vegenui Farm. This year’s cycle of crop failures and repeated owl attacks on their poultry gave Steven and Becca a crisis of perspective. They began to rethink using the traditional pastured poultry model on Balsam Gardens, and decided they needed a more integrated system between their vegetable and animal production methods for their scale of farming. Instead of trucking in chicken liter from around the country, why not use the resources they already had on the farm! After crunching the numbers a bit, Steven found he could raise up to 4,000 chickens on an acre of garden space, and get 20 tons of chicken manure to add organic matter to the soil. A no brainer!

So, they converted the shelters for the turkeys into turkey tractors by closing off the ends. Each tractor is 10 feet wide covering two beds and pathways, and is rotated across the garden so it covers every inch of space. The birds are kept fairly dense for maximum impact, but are moved frequently. They are considering supplementing the diet of the turkeys by cutting and carrying in plant material since they no longer have as much access to open pasture, after they see how the quality of the meat changes after this year. To keep predators out, the three turkey tractors are surrounded by a 48 inch tall Premier 1 moveable electric mesh fence, that they to charge with a 1 joule suitcase style solar charger.

With the rain setting in again, Becca and Steven welcomed us into their home where we enjoyed another delicious and abundant potluck complete with a Balsam Gardens roast turkey! Thank you to those who were able to come and to Becca, Steven and the Balsam Gardens crew for sharing their poultry wisdom and hosting such a great CRAFT event!

CRAFT is a year-round farmer training collaborative that offers farmers and their interns networking and learning opportunities. Membership is rolling, so join anytime! For more information or to join, click here.  Or contact Cameron Farlow, Organic Growers School Farmer Programs Assistant at 828.338.9465 or

CRAFT at Green Toe Ground Farm

October 29, 2012

ImageOur final CRAFT tour of the season was graciously hosted by Nicole and Gaelan of Green Toe Ground in Celo, NC on October 7th. We were greeted by cloudy skies once again, and once again our dedicated CRAFT members braved the rainy weather and chilly conditions to come and learn about the day’s theme – an Introduction to Biodynamic Farming. We are grateful to Nicole and Gaelan for taking the time to share their passion for Biodynamic growing and inviting us to their farm.

As Gaelan put it, “This farm has been a lot of things in our 11 years.” As farm businesses tend to do Green Toe Ground has evolved from a CSA model vegetable farm when they started out to now focusing primarily on their direct markets selling at three Asheville Tailgate markets, and raising animals.

While they have always grown with organic methods, about nine years ago Nicole and Gaelan ventured into the realm of biodynamic growing. Nicole explained that biodynamic farming is the most common organic agriculture system worldwide, but it has yet to gain a widespread following here in the U.S. Rudolph Steiner, an Austrian scientist and philosopher, developed the Biodynamic growing system in response to the use of chemical fertilizers just emerging during that era.  He envisioned a system of farming that emphasizes a holistic and intentional understanding of how the soil, plants, animals and the larger universe are interrelated. Sowing and planting is based on an astronomical calendar following phases of the moon, sun and planets. In the Biodynamic model the farm is the center of human life, with everything else radiating out. The cow is the ultimate base for that operation, chosen for its personality, relation to the earth, and manure. Manures and compost are main sources of fertilization on a biodynamic farm. The intentional preparation of a compost pile serves as the metabolism on the farm in the same way a cow’s digestion system functions – a complete breakdown of organic material producing a fertilizer rich in minerals and active microbial life.

Image To enhance the compost a series of nine fermented and herbal preparations are made throughout the year. They are either inserted in the compost pile in small doses or sprayed on the soil or plants to enliven the soil with the different attributes and minerals contained in each preparation. The different preparations make use of common herbs like nettle, yarrow, valerian, oak bark and dandelion and several are prepared using cow horns or the metabolic system of a slaughtered cow. These particular herbs are thought to contain high amounts of particular minerals they suck up through their growing process, and are then made available to the soil in the preparations.

A biodynamic farmer farms not for the plants but for the soil. Gaelan explained that when they started growing their soil was very sandy, and didn’t hold organic matter well. But after increasing their focus on the soil with biodynamic methods their soil quality has greatly improved, and he is able to water half as much during the summer months. The greatest virtue of biodynamic farming Gaelan asserts is that it provides a reason to study your farm, be intentional and create an intense relationship with the land.

While Biodynamic agriculture is ultimately designed to be a do-it-yourself model, making the preparations is a community aspect of the process and in other parts of the world where Biodynamics is more popular community members will slaughter a cow and make the preparations in large batches. This scenario is too labor intensive for Nicole and Gaelan to complete each year as a single farm. Fortunately, they are able to purchase preparations through the Josephine Porter Institute based in Virginia.

The biodynamic approach also strongly emphasizes integrating raising animals with crop production, and Imagemaintenance of the land. We were able to see how Gaelan and Nicole have done this by raising 6 ewes, selling lamb meat in the spring, and selling handspun fleece allowing them to maintain their open fields and increase their economic viability by having multiple animal products to sell. We also visited an overgrown sloped field where they have been gradually moving 4-5 Yorkshire pigs who in their own pig way will bust up the sod, eat crab grass and other weeds, and deposit their manure, enhancing the field for growing vegetables.

If you are interested in learning more about Biodynamic agriculture Gaelan and Nicole suggest starting with the Josephine Porter Institute, and if you’re really brave reading Rudolph Steiner’s work Agriculture Course: The Birth of the Biodynamic Method. You can also look into the Demeter Biodynamic Research Institute which provides Biodynamic certification and is a worldwide standard.

For our much loved potluck, Gaelan fired up the pizza oven and we feasted on fresh made pizza pies, abundant salads, and winter squash pie – a great way to cap off the CRAFT tour season. Huge thanks to Nicole and Gaelan again for hosting us and sharing their insight into the world of Biodynamic farming.


CRAFT is a year-round farmer training collaborative that offers farmers and their interns networking and learning opportunities. Membership is rolling, so join anytime! Go ahead and get signed up for next year. For more information or to join, click here.  Or contact Cameron Farlow, Organic Growers School Farmer Programs Coordinator at 828.338.9465 or