Welcome to the June edition of the Seed Bin - High Mowing Seeds Online Newsletter!
Under normal circumstances (if such things exist), the old adage “April showers bring May flowers” will often hold true, at least in general. This year in Vermont, however, warm April sun gave way to record-setting rain in May, making for a somewhat confusing and sometimes challenging beginning to the season.
As the calendar flips to June, the promise of brighter skies is on the lips of forecasters, and the season marches on, puddle-strewn fields notwithstanding. As the wet gives way to warmth, the plants respond and flourish; unfortunately, weeds are no exception to this, and we must now start turning our attention to integrating our weeding strategy into our operation. This month’s feature article, “10 Steps Toward Organic Weed Control” by Vern Grubinger, Vegetable and Berry Specialist with UVM Extension, will help stimulate gardeners & growers alike in their planning and preparation in dealing with this universal challenge.
Weeds aren’t the only challenges to emerge with the warm weather; insect pests are starting to reappear, too, and in the June Pathology Report, Dr. Jodi Lew-Smith will give you some strategies on how to deal with them. I'll be filling in a brief Farm Rundown in Charlie's absence, and in this month’s Ask the Grower, we take a stab on managing for clubroot, a fungal infection attacking crucifereous crops like cabbage, broccoli, and radish. The Recipe of the Month for June is all about peas; a few recipes will inspire you to make a meal of this tasty vegetable.
Thanks for Reading, and Happy Planting!
In This Issue:
- 10 Steps Toward Organic Weed Control, by Vern Grubinger, Vegetable and Berry Specialist with UVM Extension
- Pathology Report from HMS Plant Pathologist Dr. Jodi Lew-Smith
- On-The-Farm Rundown with Jacob Racusin
- Ask the Grower
- Weekly Featured Products On Sale Now
- Recipe of the month, and more!
10 Steps Toward Organic Weed Control
by Vern Grubinger, Vegetable and Berry Specialist with UVM Extension
About one third of Vermont's vegetable farms are managed organically. On many others, herbicides are used only on a few of the crops. Vegetable farms here and throughout New England are relatively small, and tend to have many plantings of highly diverse crops, making it a hassle to spray different materials at different times. Necessity being the mother of invention, growers are finding ways to keep ahead of weeds using only cultural and mechanical methods. While some battles are lost, some growers are winning the war and their fields are kept remarkably clean without herbicides.
Many of the tactics below are commonly used by the organic growers in New England, and may have application to other regions and larger scale of production. Here are 10 steps toward successful non chemical weed control:
1) LOWER WEED PRESSURE by managing your weed seed bank to reduce the need for cultivation and hand hoeing.
• Thoroughly compost animal manures to kill off weed seeds, or avoid using manure altogether.
• Keep weeds from going to seed: cultivate solely for that purpose, or hand-pull, if necessary.
• Reduce weed influx by keeping alleys and field edges mowed or harrowed.
• Power wash tillage equipment after use in fields with a noxious weed problem.
2) DIVERSIFY ROTATIONS to keep a particular weed from proliferating.
• Try to alternate crops with different tillage requirements or time of planting.
• Include small grains or sod crops in the rotation if possible, to vary the habitat for weeds.
3) USE COVER CROPS because they compete with weeds while providing other benefits.
• Select species for rapid growth that can starve weeds of light and nutrients. In the northeast, overwintering hairy vetch plus rye or hairy vetch plus oats mixtures are popular as a spring cover crop. Buckwheat, sorghum-Sudangrass, or Japanese millet work well in the heat of summer. Ryegrasses, oats or other small grains provide fall cover and winter erosion control.
• Sow at high rates, drill the seed and even irrigate if necessary to assure thick stands and rapid establishment of cover crops.
• Regular incorporation of cover crops (green manuring) enhances soil tilth, making cultivation easier. Since frequent cultivation can harm soil structure, it is important to compensate by adding clean organic residues whenever practical.
4) FEED THE CROP, NOT THE WEEDS by manipulating fertilizer placement and timing.
• Avoid pre-plant broadcasting of soluble nutrients that may be more readily utilized by fast-growing weeds than slow-growing crops, and may even stimulate weed germination.
• Apply fertilizer near the rows where it is more likely to be captured by the crop.
• When using expensive bagged organic fertilizers, band at low rates at planting or sidedress; rely on mid-season release of nutrients from compost and/or green manures for primary fertility.
5) PICK THE RIGHT TOOL FOR THE JOB. Cultivation is critical to weed control on organic farms, and doing it right requires a variety of tools that can be matched to the weed, crop and soil situation. Over the season, different tools are needed as the crops and/or weeds get larger.
• Blind, "over-the top" cultivation controls very small weeds, just germinated or emerged, before and sometimes after planting. The entire surface of the field is worked very shallow using flex-tine cultivators (e.g. Lely weeder), or rotary hoes.
• Shallow between-row cultivators such as basket-weeders, beet-hoes, or small sharp sweeps are used to cut off and uproot small weeds after the crop is up. These can get very close to the crop when it's small, without moving much soil into the row, and may be the only tools used on delicate crops like leafy greens.
• As vigorous crops grow, soil can be thrown into the row to bury in-row weeds using rolling cultivators (e.g. Lilliston), spyder wheels (e.g. Bezzerides), large sweeps or hilling disks. Some of these tools can be angled to pull soil away from the row when plants are small, and later turned around to throw soil back on the row during subsequent cultivations.
6) COMBINE TOOLS to cover the different zones in the field.
• Between-row, in-row, and wheel-track weeds must all be attacked.
• Watch out for narrow strips that are missed because they pass between too-few tools.
• Front-mounted or belly-mounted tools plus rear-mounted toolbars facilitate combinations that can assure complete coverage.
7) SET UP FOR SPEED to minimize cultivation time and expense.
• Perfectly straight rows and alert tractor drivers are essential
• Uniform row spacing across comparable crops enhances the utility of a cultivation set-up.
• Consider multiple-row units; gauge wheels are helpful on wide units or if fields aren't level.
• With frequently-used tractor-mounted cultivators, get them set just right and leave them on all season to avoid repeated mounting and adjustment.
8) TIMING IS EVERYTHING: get the weeds while they're small, before the field looks weedy.
• Very shallow cultivation of "white thread" weeds can minimize bringing up more weed seeds.
• Keep an eye on the weather and try not to get beat by the rain; if you do, be ready with the heavy artillery - more aggressive tools for bigger weeds, when you can get in.
9) CONSIDER STALE SEED BEDS OR STALE ROWS using flame-weeders.
• Prepare soil for planting, then use a flamer to kill very small weeds without disturbing the soil.
• One or two flamings are used, just before and/or after planting, but prior to crop emergence.
• Single burners flame just the crop row, multiple burner units cover a whole bed.
• Backpack, push-type and tractor-mount units are in use.
10) EXPERIMENT to fine-tune your weed management tactics.
• Start on a small scale with tools and techniques that are new to your farm.
• Identify your problem weeds and compare different combinations of rotations, cover crops, and cultivation tools for their effectiveness in providing control.
• Keep an eye out for new tools, or new ways to use old tools.
• Leave a "control" row or section untreated, so you can see the effectiveness of your tactics.
For more resources on this topic, please consult the following websites:
Pathology Report for June 2006
by HMS Plant Pathologist Dr. Jodi Lew-Smith
Basics of Plant Pathology: Organically-compatible control of insect pests, Part 1
We look at insects this month, as they are already getting moving (a step ahead of us as usual!). In a recent survey of 68 organic vegetable growers in Vermont, conducted by Katrina Hardt of Craftsbury, the top three serious insect pests were Colorado potato beetle on potato, eggplant, and tomato; striped cucumber beetle on cucurbits; and the tarnished plant bug on peppers, lettuce, eggplant, strawberries, and raspberries. This week, we’ll discuss the first two, Colorado potato beetle and striped cucumber beetle. Next week, we’ll look at the tarnished plant bug, and a few others.
Colorado potato beetle (CPB) is familiar to anyone who’s grown potatoes for more than a single season. The adults are yellow & black striped beetles, and they lay copious numbers of orange eggs that hatch into red larvae with huge appetites. They strongly prefer potatoes, but will eat the leaves of tomatoes and eggplants if you take a break from growing potatoes for them (from their perspective). Nearly half of the respondents to the above-mentioned survey say that they handpick the beetles and larva, while a minority of farms control by means of crop rotation. Crop rotation can be effective if isolation distances are at least a ½ mile, thick cover crops follow the potatoes to inhibit beetle movement out of the field, and early trap crops are planted in the new field to allow for elimination of migrating beetles by flaming or vacuuming (see www.nysaes.cornell.edu/recommends
). Also there are now available two potato varieties, Elba and Prince Hairy, that show significant resistance to CPB.
At present there is only one organically-compatible chemical/biological control for the beetles, which is spinosad, a mixture of the two most active naturally occurring metabolites (spinosyns A and D) produced by the soil actinomycete Saccharopolyspora spinosa
. As an OMRI-approved product it is available as Entrust™, made by Dow AgroSciences. Spinosad is fast-acting and highly effective against CPB, and is used by a number of organic farmers. Unfortunately, the other chemical/biological control, Bacillus thuringiensis ssp. tenebrionis
(Bt) is no longer available in an OMRI-approved formulation, and thus certified organic growers do not have a spray alternative to spinosad at the moment. The problem with spinsoad is that it works so efficiently that it provides a powerful evolutionary bottleneck for selecting resistant individuals. Thus, even if only 1 in a million CPB has some resistance, we’re going to find that individual relatively quickly and give it a strong selective advantage. If we have the option to spray Bt in rotation with spinosad, chances are that the one in a million individual resistant to spinosad would not also be resistant to Bt, and thus we’d be ameliorating the selection pressure for spinosad resistance. And so, for those of you who operate under organic management but are not certified by the USDA, you might consider using Bt in rotation with spinosad, as the problem with Bt is not with the compound itself but with the lack of available information on the inert materials used in the commercial formulation of the product. For those who are certified organic, consider leaving an unsprayed trap crop where susceptible individuals can survive to mate with any resistant individuals, thereby diluting resistance.
The other beetle on our black list is the striped cucumber beetle, which is unfortunately not closely related enough to CPB to be controlled by similar means. Striped cucumber beetle is really rather an amazing beetle, in that it is resistant to almost all of the usual organically-allowable control substances, and is controlled in conventional systems by heavy-duty insecticides. The beetle feeds heavily on foliage of young cucurbit plants, as well as developing flowers, leading to set-backs in growth and yield. And if this wasn’t bad enough, it is also the major vector for bacterial wilt, a devastating disease that can spread across an entire field. Cucumber beetles are attracted to cucurbitacins, a bitter compound originally produced by plants of the cucurbit family to aid in defense. In a twist of Darwinian irony, the beetles are not only undeterred by the compound, but are attracted to it, and there is some indication they might sequester the compound in their elytra as defense against their own predators.
Where beetle pressure is light to moderate, a number of organic growers have had success with applications of kaolin clay (Surround™) to confuse and deter the beetles. The clay can be applied either by dipping transplants into a solution or spraying it on after planting. Other growers have had success with planting trap crops of varieties that are particularly high in cucurbitacins, with blue hubbard winter squash as the typical choice for this purpose. This method is most effective when the crop you are growing is significantly lower in cucurbitacins than the trap crop, when the trap crop fully surrounds the main crop, and when the trap crop is planted early enough to attract all the beetles in the area before the main crop goes in.
Where beetle pressure is heaviest, however, or where the main crop is high in cucurbitacins, the most effective control measure is to carefully cover the whole crop in row cover immediately after planting, and keep the cover on until bloom begins.
We’ll get to tarnished plant bug and a few others next month!
On-The-Farm Rundown - June 2006
by Editor Jacob Racusin
As you can imagine, this is an awfully busy season on the HMS Seed Farm - our busiest time of the year, in fact. With the break in the weather we've been given, Farm Manager Charlie Rowland has been spending all his waking hours in the field; I'm filling in this month with a brief synopsis of what's happening. Stay tuned next month, and hopefully Charlie will be back with a full report.
This has been the season of planting; since our last correspondance, thousands of plants of melons, watermelons, squash, lettuce, tomatoes, and brassicas have found their new, permanent homes in the fields at Rooster Ridge. Direct-seeded brassicas, beans, corn, peas, and edamame soybeans are also nestled in the ground, and emerging from the soil. The trial gardens are about 70% of the way planted out, with only a few stragglers left in the greenhouse. The last round of cucurbits for production - cucumbers and a few pumpkins and squash - are also in the greenhouse, awaiting transplant. Despite the wet weather, winds, hail, and other dramatic effects of the spring, the field crops are doing quite well, and the season is off to a strong start. Cucumber beetles and tarnished plant bugs are starting to rear their heads, but are so far still under control.
Stay tuned next month for words from the mouth of Charlie himself!
Ask The Grower
This month, HMS Plant Pathologist Dr. Jodi Lew-Smith answers the question:
"Is there any way to get rid of clubroot? We don't have the space for a 5-7 year rotation..."
I'm afraid I don't have good news for you; once you've got clubroot, you're
pretty much stuck with it, at least in an organic system (conventional
growers have the option to fumigate soil). The fungus infects roots of all
cruciferous crops, which includes broccoli, Brussels sprouts, cabbage,
cauliflower, turnip, rutabaga, and radish, as well as cruciferous weeds.
If you can't do a 5-7 yr rotation, the two other options are to locate
resistant varieties and work on increasing your soil pH, as disease
incidence drops greatly in soils above pH 7.2 . Calcitic lime is more
effective than dolomitic lime, but if your soil is low in magnesium, you
might want to use dolomitic lime. Cornell recommends using hydrated lime
(calcium hydroxide Ca(OH)2) in addition to limestone. Also, increasing pH
can lead to boron deficiency, so you'd want to supplement with a boron spray
or put boron in the transplanting water if your soils are not high in boron
(note that regular Borax, sold in the detergent section of the grocery
store, is a non-synthetic source of boron that is usually allowable in
As to resistant varieties, there is a cabbage called Badger Shipper that has
at least a moderate amount of resistance, and there are some breeding lines that may result in new releases in future years.
For more info, Cornell has a great extension site at
I hope this helps; Good luck!
Have a burning gardening question? A pesky path problem? A vexing marketing quandry? Send us your questions, and we'll get you answers! We will publish one of your questions, with an answer given by one of the experienced growers on our staff, in each issue of the Seed Bin.
Send your questions to
, and please write "Ask the Grower" in the subject line.
Weekly Featured Products On Sale Now!
Every Wednesday, we unveil a new batch of three featured products that we offer to you at a discount. Maybe we have extra supply of seed, or maybe we want to show off a particular variety. Whatever the reason, you can enjoy 20% off our featured varieties
when you order your seeds online at www.highmowingseeds.com
! Just add the varieties to your cart, and your discount will be applied automatically when you checkout. And yes, all sizes of the featured products are on sale, so the more you buy, the more you save! But remember, the products are only good for a week, so buy now before the sale ends.
Recipe of the Month
Last month's essay by Chris Bohjalian on planting peas got my mouth watering, so if your peas haven't drowned yet, save these recipes for the bounty to come!
Fresh Pea Soup
Use fresh peas for this recipe. Sit yourself down with a big bowlful of peapods and begin pea'n. Shelling peas is something that comes naturally to everyone; it is a soothing ritual that inspires daydreams and puts you in the right frame of mind so that all of the creative ideas percolating under the surface of your consciousness can emerge and seem really possible. Use any fresh herb you like, but I especially like the combination of marjoram and oregano in this. Chop the herbs at the last minute to get the full benefit of their fragrance and flavor. In a light soup like this, the herbs take center stage.
1 small onion, peeled and diced
1 small clove garlic, chopped
2 T. butter
4 cups fresh peas, shelled
4 cups chicken stock or vegetable stock or water
1 tsp. of fresh oregano, chopped
1 tsp. of fresh marjoram, chopped
1. Saute the onion in butter in the bottom of a 5-quart soup pot. Add a bit of salt and cover the pot to ensure that the onions slowly become translucent and do not scorch. Add the chopped garlic and continue sauteing for an additional 3 minutes. Add the liquid and the peas. Stir in the chopped herbs with a little salt and cover. Bring to a boil and then lower the heat to simmer until the peas are tender.
2. Use a hand-held immersion blender to puree the soup into a smooth consistency. (If you prefer to use a blender, let the soup cool down and blend small batches - one cup at a time). Stir in 1/2 cup of cream and serve.
3. Garnish each serving with a sprinkling of chopped herbs and some fresh whole peas that have been blanched in salted water.
Snow Pea-Orange Salad Recipe
The contrast between snow peas and tart orange slices is a refreshing and delightful compliment to a summer meal. Using fresh orange juice as the acid in a vinaigrette is a refreshing change from the more predictable vinegar or lemon juice.
1 to 1 1/4 pounds snow peas, trimmed
1 orange, peeled and thinly sliced
2 tablespoons extra-virgin olive oil
2 tablespoons fresh orange juice
1 tablespoon white wine vinegar
1 heaping tablespoon chopped shallot
1 tablespoon chopped fresh thyme
1/4 tablespoon chopped grated orange zest
salt and freshly ground black pepper
3 tablespoons chopped cashews or slivered almonds (optional)
1. In a saucepan or large skillet, combine the snow peas and water to cover. Bring to a boil over high heat and blanch for about 1 minute. Drain and rinse with cold water. Draing again and pat dry between paper or cloth towels. Transfer the snow peas to a serving bowl and add the orange slices. Toss gently to mix.
2. To make the dressing: In a small bowl, whisk together the olive oil, orange juice, vinegar, shallot, thyme, and zest. Season to taste with salt and pepper.
3. Sprinkle several tablespoons of dressing over the salad and toss to coat. Use only enough to moisten. Sprinkle with cashews or almonds, if desired, and serve. Serves 6 to 8.
Spicy Shrimp Wrapped with Snowpeas
Asian flavors accent this delicious do-ahead appetizer.
Original recipe yield: Makes 20.
20 uncooked large shrimp, peeled, deveined
1 tablespoon minced fresh ginger
2 teaspoons vegetable oil
1 large garlic clove, pressed
1/2 teaspoon Chinese five-spice powder
20 large snow peas, stringed
1 teaspoon oriental sesame oil
1/2 teaspoon sesame seeds, toasted
2 tablespoons soy sauce
20 small wooden skewers or toothpicks
1. Combine shrimp, ginger, vegetable oil, garlic and five-spice powder in medium bowl; toss to blend. Cover and refrigerate at least 1 hour and up to 4 hours. Bring medium pot of salted water to boil. Add snow peas; cook just until crisp-tender, about 45 seconds. Drain. Rinse with cold water. Drain; pat dry. Transfer to bowl. Drizzle sesame oil and sesame seeds over; toss to coat. Set aside.
2. Heat large nonstick skillet over medium-high heat. Add shrimp mixture and sauti 3 minutes. Add soy sauce; stir until shrimp are just opaque in center and liquid evaporates, about 1 minute. Transfer to plate and cool completely.
3. Wrap 1 snow pea lengthwise around each shrimp from head to tail. Secure with skewers. (Can be prepared 6 hours ahead. Cover and refrigerate.) Serve slightly chilled or at room temperature.
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. Please note that Sale items listed in these archival issues are no longer valid.
Let's Make it Better
This is your newsletter, not ours - we just write it. Just as your comments, questions, concerns, and field experience have helped to guide our business in every way, from variety selection to customer service, we rely on your feedback to guide the creation of a publication that is informative, inspirational, entertaining, and enjoyable to read. What would you like to see more or less of? Technical advice? Seed saving tips? Tools and techniques? Information about High Mowing Seeds? We want to give you what you want, so please let us hear from you! Write to firstname.lastname@example.org
with your comments, critiques, and questions.
Thanks for reading - and responding!
Vern Grubinger, Vegetable and Berry Specialist, UVM Extension - Feature Writer
Jodi Lew-Smith - Technical, Pathology Editor
Jacob Racusin - General Editor