We drove home seven hours from the Pennsylvania Mother Earth News Fair yesterday through the rain. The remnants of Hurricane Florence. We were among the lucky people. Earlier forecasts for Florence had the hurricane raging across central Virginia.
At the Fair, I gave two workshops: Fall and Winter Hoophouses and my new Lettuce Year Round, which you can view right here. Click the diagonal arrows icon to get a full screen view.
I’ve updated my Events page again, now that the September- April “Events Season” has hotted up. I’ve added in a couple of new ones and updated some others. Click the Events tab to find conferences and fairs near you, and be sure to come and introduce yourself!
I’m giving a Premium Workshop on Friday Sept 21, 3-4 pm Classroom 7. Click the link HEREto book for that.
Feeding the Soil
In this workshop I will introduce ways to grow and maintain healthy soils: how to develop a permanent crop rotation in seven steps, and why your soil will benefit from this; how to choose appropriate cover crops; how to make compost and how to benefit from using organic mulches to feed the soil. Handouts.
Book-signing Friday 4.15 – 4.45 pm.
On Saturday there are events all day from 10am to 5pm. $26 general admission.
I’m off to the Southern Sustainable Agriculture Working Group Conference in a couple of days. I’m presenting Intensive Vegetable Production on a Small Scale. At the link you can view a version of the slide show with lots of bonus material! (It was hard to cut the show down to 75 minutes!) I also had a lot of material on sustainable management of pests, diseases and weeds which I couldn’t even fit in the handout, so I’m posting that here.
Biointensive Integrated Pest Management
The goal of IPM is to deal with problems in a systematic and least toxic way. Biointensive IPM goes further in emphasizing non-toxic methods.
There are four steps of IPM: prevention, avoidance, monitoring and suppression.
Sustainable Animal Pest Management
Prevention: Focus on restoring and enhancing natural balance and resilience to create healthy plants and soil, better able to withstand attacks. Maintain soil fertility, good drainage and soil structure; plant resistant, pest-tolerant, regionally adapted varieties; grow strong plants; practice good sanitation,
Avoidance: The next stage is taking actions to reduce the chances of a specific pest taking over. These actions are also known as physical controls. All these methods reduce problems without adding any new compounds into the soil. Use good crop rotations, remove pest habitat, deter known pests, use rowcovers, ProtekNet, low tunnels, high tunnels. Provide habitat for bats, insectivorous birds, spiders, birds of prey and rodent-eating ground predators (snakes, bobcats). Physically remove pests by hand-picking, spraying with a strong water spray, flaming, vacuuming, or by using a leaf-blower to blow bugs into a collecting scoop; solarize soil in the summer to kill soil-dwelling pests, as well as diseases.
Monitoring (is action needed?) : regularly inspect your crops, find out when conditions are right for an outbreak of a particular pest, set traps and lures (sticky traps and pheromone traps) so you know when pests arrive or hatch out. Identify the pests you catch, keep records each year. Be prepared.
Suppression: When the established action level for a particular pest has been reached, and prevention and avoidance strategies have been exhausted, bio-logical, microbial, botanical and mineral control measures can be used to reduce pest damage of crops to an economically viable level, while minimizing environmental risks. There are four types of sustainable bio-intensive control measures to choose from, starting with the least toxic solution:
Biological control involves either introducing beneficial predators or parasites of the pest species, or working to boost populations of existing resident predators and parasites.
Microbial controls refer to the use of fungi, bacteria, and viruses to kill pests.
Botanical control uses plant-based products for pest control. An example is neem oil,
Inorganic (mineral) controls, also known as biorational disease controls, make use of oils and soaps.
Sustainable Disease Management
Diseases need a susceptible host and the presence of a pathogen and suitable environmental conditions. Plant pathogens can be soil-borne, foliar-borne, seed-borne, or a combination of seed-borne with one of the others.
A. Soil-borne pathogens can live in the soil for decades, so long crop rotations are needed. Club Root is one. Fusarium oxysporum and Verticillium dahliae are two soil-borne fungi. Fusarium survives a long time in soil without a host, and can also be seed-borne.
B. Foliar pathogens need foliage! They die in soil in the absence of host plant debris, so practice good sanitation. Late blight (Phytophthora infestans) is a good example of this type of disease: it does not carry over in the soil, on dead plants, the seeds or the stakes. Cucurbit angular leaf spot (ALS) bacteria (Pseudomonas syringae) overwinter in diseased plant material and on the seed coat
C. Seed-borne pathogens: Lettuce mosaic virus is an example of a disease in which the seed is the main source of the pathogen and if seed infection is controlled, the disease is prevented. Other seed-borne pathogens may start life as a foliar-borne or a soil-borne pathogen. Infected seeds will produce infected plants even in clean soil. Pathogens can infect the seed via several routes: The parent plant can become infected by drawing soil pathogens through its roots up into the seed; Pathogenic spores can float in on the air (Alternaria solani, early blight of tomatoes; Anthracnose fungus that affects nightshades, watermelon and cucumber); Insects that feed on the plant can transfer the disease (striped cucumber beetles vector bacterial wilt, which is caused by Erwinia tracheiphila); Insects that pollinate the plant can bring infected pollen from diseased plants.
Prevention and Avoidance (cultural controls)
Apply good compost and maintain healthy, biologically active soils; Optimize nutrients and moisture for crop vigor;
Practice good soil management (eg timing of tillage) to preserve maximum diversity of microorganisms; Use rotations to minimize disease and improve the environment for natural enemies of diseases; Time your plantings to avoid peak periods of certain diseases; Practice good sanitation of tools, plants and shoes; Use seed hot water and bleach treatments; Plant locally adapted, resistant varieties; Provide good airflow; Use mulches to reduce splashback from soil to plants; Use drip irrigation to reduce moisture on foliage; Use farmscaping to encourage beneficial insects.
Monitor crops for problems
Make a regular tour of your crops once a week to monitor growth and health. Keep good records. If you see a problem, identify it. Plant Diseases Diagnostic lab can help. The mere presence of a disease does not automatically require spraying. The economic threshold (ET) or action level is the point at which losses from the disease warrant the time and money invested in applying control measures.
When control measures are needed
Physical controls: Removing diseased plant parts, protecting vulnerable plants with rowcovers or sprayed kaolin barriers, mulching to isolate plant foliage from the soil, tool and shoe sanitation, soap washes for foliage, hot water or bleach seed treatments, and soil solarization to kill disease spores are all methods that reduce problems without adding any new substance into the mix.
Biological controls: Beneficial animals and insects are more common in insect pest reduction than in disease control, but the use of milk as a fungicide qualifies as a biological control. Plants in danger of developing powdery mildew can be sprayed weekly with a mix of one volume of milk with four volumes of water. When exposed to sunlight, this is effective against development of fungal diseases.
Microbial controls: Homemade microbial remedies employ liquids (simple watery extracts and fermented teas) made from compost. For a simple compost extract, mix one part mature compost with six parts water. Let it soak one week, then strain and dilute to the color of weak black tea. Fermented compost tea can deal with many maladies. If your strawberries are prone to Botrytis, apply fermented compost tea every two weeks, starting when the berries are still green. See ATTRA or the Soil Foodweb site for how to make fermented compost teas.
Botanical controls: Using plant-based products to reduce disease. Neem oil, as well as being a pesticide, forms a barrier on foliage that prevents some fungal diseases from establishing. It degRolling biodegradable plastic mulchdegrades in UV light in four to eight days and must be reapplied if the disease organisms are still around. Like all broad-spectrum insecticides, neem can kill beneficials as well as pests, so caution is needed if it is used. Garlic can be used against fungal diseases: blend two whole bulbs of garlic in one quart (one liter) of water with a few drops of liquid soap. Strain and refrigerate. For prevention, dilute 1:10 with water before spraying; for control, use full strength. Kelp sprays are also used to generally boost the resistance of plants to pest, disease and weather-related problems. Biofumigation by incorporating Ida Gold and Pacific Gold mustards into the soil
Inorganic controls, also known as biorational disease controls: These include Bicarbonates (baking soda) one teaspoon (5 ml) in one quart (one liter) of water, with a few drops of liquid soap as a spreader-sticker against fungal diseases. Oils and soaps copper and sulfur products, as part of a prevention program (not a cure). Several of these need to be used with caution if the plants and the planet are to survive the treatment.
Sustainable Weed Management
Weeds compete with crops for sunlight, water and nutrients, and can encourage fungal diseases by reducing airflow. Too-frequent cultivation to remove weeds can leave the soil more prone to erosion. Each tilling or deep hoeing stirs air into the soil and speeds combustion of organic matter. Most weeds respond well to nutrients, especially nitrogen. If you give corn too much nitrogen, even as compost, its productivity will max out and the weeds will use the remaining nutrients.
Remove weeds at their most vulnerable stage, or at the last minute before the seedpods explode —ignore weeds doing little damage. There are different types: annuals and perennials; stationary perennials (docks) and invasive perennials (Bermuda grass); cool-weather and warm-weather types; quick-maturing and slow-maturing types; “Big Bang” types (pigweed) versus “Dribblers” (galinsoga).
Preventing weeds from germinating
grow vigorous crops adapted to the locality,
close spacings, leaving less space for weeds,
switch between spring and summer crops in rotation,
drip irrigation rather than sprinklers,
mulch to bury short-lived weed seeds
plant promptly after cultivation,
transplant rather than direct sowing,
Multiple cropping, relay planting
Cover crops, including no-till, reduced till
Encourage seed-eating birds, insects, worms, mice
Reducing weed seeding
Reduce weed seed banks to 5 % of original levels when weeds are not allowed to seed for 5 consecutive years.
Timely cultivation, Mowing, Flaming, Grazing by cattle, chickens, ducks, geese
Using post-emergence organic weed killers: corn gluten, vinegar, flaming
Reducing seed viability
Most weed emergence happens within two years of the seeds being shed.
Seeds lying on or near the soil surface are more likely to deteriorate or become food for seed predators than buried seeds, so delaying tillage generally reduces the number of seeds added to the long-term seed bank
If they do not get eaten, dry out or rot, seeds on top of the soil are more likely to germinate than buried seeds.
Small, short-lived seeds of weeds with no dormancy period, such as galinsoga, will almost all die within a year or two if they are buried a few inches. Till and mulch to bury short-lived weed seeds
Longer-lived seeds (pigweed, lambsquarters, velvetleaf) if buried, may remain viable and dormant for years
Avoid deep tillage if you have long-lived-seed weeds
stale bed techniques draw down the seed bank in the soil
Reducing the strength of perennial weed roots and rhizomes
Apical dominance: when a rhizome grows a shoot, chemicals from that shoot prevent other nearby nodes from sending up shoots.
On long rhizomes, after a certain length, the dominance effect is too weak and another node can grow a shoot.
When rhizomes are cut into pieces during tillage, the apical dominance is lost and each piece can grow a shoot
But such shoots may be weak – Cultivate again before the new shoots have grown enough to send energy back to the roots, or pull out the pieces to dry on the surface: the depleted pieces of root or rhizome may die.
It’s more effective to wait time until the new top growth has drawn down the plant’s reserves (in the roots) before hoeing or pulling, than to go almost daily after every sprig.
Removing top growth whenever the weeds reach the three- to four-leaf stage can be most effective
My salad greens ideas include quick-growing Tokyo Bekana, Maruba Santoh and mizuna; purslanes; baby salad mixes including komatsuna, Yukina Savoy and Jewels of Opar; and garnishes like Spilanthes cress, red shiso, saltwort and microgreens. For years I have been perfecting the techniques needed to grow year round lettuce in Virginia (you can read about that in my book Sustainable Market Farming). It’s good to have more strings to our bows so we can be resilient in the face of unpredictable weather and changing climate.
The crop I am most excited about this summer is Jewels of Opar, also known as Fame flower. Southern Exposure Seed Exchange sells the seed, and have an interesting blogpostabout this crop by Irena Hollowell. She heads her post “A Heat-Tolerant Leafy Green Vegetable Disguised as a Flower”. As you see in the July photo below, the plants continue to produce fresh leaves even as they make light sprigs of pretty little flowers and attractive fruits.
The cover article of this Growing for Market issue is Know Your Knots by Joanna and Eric Reuter of Chert Hollow Farmwho I have mentioned before (Eric commented about frosted strawberry flowers on my previous post.) This is an example of the hands-on useful articles in Growing for Market – written by farmers for other farmers, with information that is sure to save time, and even materials. I’m looking at the square-lashed storage rack for keeping rottable things off the ground. I damaged our cold frame lids last year by leaving them stacked on edge on the ground all summer. We used to store them in the shed, but an increase in the other stuff stored in the shed meant no room left for seasonal storage of bulky coldframe lids. Now I know how to store them outside without damage. One of our mantras is “Never make the same mistake two years running!”
In this same GfM issue, Patty Wright has an article about Community Supported Agriculture Farms (CSAs), encouraging us farmers to look at our aspirations and celebrate the diversity of CSAs. The two principles of shared risk and community support are at the heart of the CSA movement, and there are different ways that these are put into practice. The more common aspirations we can share, the stronger the movement will be.
Gretel Adams has an article about attractive foliage for cut flower arrangements in spring, summer and autumn.
Lisa Kivirist and John Ivanko, who I meet periodically as fellow presenters at the Mother Earth News Fairs have a new book Homemade for Sale: How to Set Up and Market a Food Business FromYour Home Kitchen, published by New Society Publishers. An excerpt from the book is in this issue. It covers how Cottage Food Laws apply to people making food products and selling them to neighbors and community. Many growers would like to process some of their crops for sale in the quieter parts of the season. This book will give inspiring examples and help you stay on the right side of the law.
The season of tending millions of seedlings is winding down. We are planting out more every day. yesterday we planted our maincrop slicing and cherry tomatoes. (The early crop is in the hoophouse).
We’re continuing our relentless schedule of planting out 120 lettuces each week. It’s time for us to set out celery, Malabar spinach and okra. And we’re about to launch out into the row-crop area of the garden again. First the big planting of 540 Roma paste tomatoes.
We have measured and flagged the six 180′ rows. We need to run the drip tape, test it, fix problems, then unroll the biodegradable plastic mulch, then stake and rope where we want the rows to be, so we plant in straight rows. Then we’ll install the metal T-posts without spearing the hidden driptape (easiest if we run the irrigation while we do that, so the drip tape is fat and easier to locate.)
We’ll be transplanting for two hours a day for the next 4 weeks.
This is the time of year I start selecting and labeling plants to save seed from two of my favorite open pollinated vegetable varieties. For crops where the fruit is the edible part of the plant, it’s very easy. You simply let the fruit get a bit over-ripe, then use a wet seed extraction process to get the seeds.
We have been selecting Crimson Sweet watermelon for early fruiting, large size, disease-resistance and flavor, and this seed is now sold by Southern Exposure Seed Exchange as Crimson Sweet Virginia Select. (They supplied this photo.) We used to mulch our watermelon patch with hay, which actually delays ripening, because it cools the soil. So working to get earlier watermelons was very important to us. Using the biodegradable plastic mulch warms the soil, causing the melons to ripen earlier. The combination of plastic mulch and seed selection means we now get melons when it’s hot, and not just at the end of summer as we did previously!
Once the melons start to form on the vines, I walk through the patch and write a number on the skin of big melons with healthy foliage. I just did this last week. I numbered 1-42, using a grease pencil. Large early size is related to early ripening, but it’s not the same thing. If the numbered melon doesn’t actually ripen early, I don’t save seed from it. Once the melons stat to ripen, I look through the patch once a week and choose 6-8 ripe numbered melons to save seed from. I cut open the melon and eat a big spoonful from the heart. If the flavor is only so-so (I have high standards!) I don’t save seed, but just put the melon in the kitchen for everyone to eat. I keep a log book and record the harvest date, size and flavor. Then I scoop the seedy part of the melon into a seed bucket and the edible flesh into a clean bucket for us to eat later.
I ferment the seed for a few days, then wash and dry it. Usually I do one batch of seed a week for about 6 weeks, from late July to early September. Ones not ripe by then can’t qualify as early-ripening!
On a different day of the week, I collect ripe fruit from the Roma tomatoes. Here we are selecting for earliness and disease resistance, particularly resistance to Septoria leaf spot, which used to plague us.
As the first fruits ripen, I walk along the rows with two colors of biodegradable flagging tape. I use red tape to mark plants with early ripening fruits (and average or better foliage). Later in the season I also use another tape to mark plants with particularly healthy foliage and a reasonable yield of fruit. I tie the tape to the neighboring T-post, with a bow on the side of the post indicating which direction from the post the chosen plant is. Early in the season all the foliage is healthy – the leaf diseases develop as the season goes on.
Once a week I harvest a couple of ripe tomatoes from each marked plant. I don’t extract seed immediately. but store the bucket of tomatoes for a few days in a secret place (where no-one will find and eat them!) This lets the fruit and seeds mature a bit more. To save the seed, I cut the tomatoes lengthwise and spoon out the seed. I wash the tomatoes first, so I can then save the flashy “shells” for making salsa or tomato sauce. The tomato seed goes through the same kind of fermentation process that we use for the watermelon seed. This is a surprisingly easy way to separate the seed from the extraneous stuff, and in addition, fermentation kills off the spores of certain diseases.
This photo of Septoria Leaf Spot is from Cornell University Long Island Horticultural Research and Extension Service.
With both these crops, we get both food and seed from the same fruits. And we are developing the varieties in ways that work best in our climate and under our methods of growing these crops. Plus I get to sell seed to SESE, as well as have enough for ourselves. The process of saving our own seeds involves selecting from at least 25 plants, to ensure some genetic diversity, and this inevitably leads to saving more seed than we need just for ourselves. Happily, that means we can supply this seed to others who want similar traits in their crops.
Now that we’ve got the garlic harvest behind us, as well as the June potato planting, we are turning our attention to weeding and mulching. We have hoed our leeks, our recent corn plantings, and the newest beans, squash and cucumbers. We have sowed some more beans, and some more cabbage and broccoli for fall. We weeded and mulched the eggplant, okra and slicing tomatoes.Eggplants are almost ready! Tomatoes are getting ripe! We walked through the watermelon patch and pulled out the weeds poking through the biodegradable plastic mulch, where it has started to crumble. Last week we did the same with the sweet potato patch.
We’re getting ready to pull the weeds in the big Roma paste tomato patch, which also has biodegradable plastic mulch. Usually most of the patch is in a mowed no-till cover crop, but last winter we had colder-than-usual weather, and poorer-than-usual stands of legumes in our cover crops. So we decided to add compost, disk the cover crop in and use bioplastic for the whole Roma plot. As I said in my previous posts about bioplastics, they are especially good for vining crops, and although tomatoes can be grown sprawled on the ground, we don’t do that. We stake ours and use Florida String Weaving.
So when the bioplastic starts to break up, we need to cover the ground with something else. We unroll big round hay bales between the rows. (We planned for this, so the rows are just the right space apart.)
Another big task this week (and next) is clearing our spring sown carrots and beets, for storage in our walk-in cooler. Then we’ll steadily eat our way through them, as well as pickle some beets. Rumor has it that we still have some pickled beets from last year in the basement, although I haven’t checked that out. Carrots and beets get woody if left in the ground too long, especially in hot weather. So it’s better for us to harvest them all and store them under refrigeration.
Actually we had to jump to it and clear one bed of carrots this morning, because the bed is needed next Monday for more sowings of fall brassica seedlings. We’ll add compost, till it, then rake. The crew cleared the five 90′ rows in just half an hour, to my amazement. We got 3.5 big bags. I don’t think anyone weighed them, but they were the standard size 50# carrot bags, but not so full. Maybe 150# total. They were sown 3/15. We have two beds that were sown earlier, but we don’t need those beds quite so urgently!
Somehow we didn’t seem to have taken any pictures of our own asparagus beans. We usually grow a purple one, either Red Noodle or Purple Pod. We like them to provide some eye-catching visual variety among the greens and pale colors of other veggies in a mix, and the “short stick” shape adds another kind of difference.
They are an easy crop to grow in warm weather. Once you have set up their required tall trellis, you can pretty much stand back and let them grow. They aren’t troubled by Mexican bean beetle or (in our experience) by diseases. They can tolerate some amount of drought. One short row can feed you all summer. We grow just about 34′ for 100 people, and get plenty. Having said that, I wouldn’t give up green beans for these – I don’t like the flavor as much as green beans, hence my suggestion to use them in mixed dishes.The mild flavor has been compared to a mix of bans, asparagus and mushrooms. Quite different from green beans.
Chop the pods into one-inch pieces for cooking. Their real strength is as part of a stir-fry or a curry. Their unique flavor is brought out best by dry-frying in a hot wok with peanut oil, garlic and soy sauce. You can also stew them with tomato sauce; or boil, drain, and season with oil and lemon juice; or simmer in oil or butter with garlic. The pale green varieties are meatier and sweeter than the dark green ones, which have a stronger flavor. In soups, Chinese Red Noodle, with a small amount of vinegar added, produces a deep wine-red broth. Asparagus beans are a good source of vitamins A and C.
Although they are also known as Yard-long beans, you don’t actually want to let them grow that big, or they get puffy and tough. Harvest while they are still thinner than a pencil,about 10-15″ long, and before the beans develop. We pick ours three days a week, right through until the frost kills the vines.
Also in this issue of Growing for Market is an article by the editor, Lynn Byczynski, about food safety of leafy greens in summer. Triple rinsing your greens in potable water, and spinning out the water before cooking (or eating raw), will greatly reduce the likelihood that you let any nasty micro-organisms into your lunch.
Brett Groshsgal has written a good article about Lyme Disease, which we farmers risk more than the average population. He describes the symptoms (never mind looking for that elusive bulls-eye rash, which 40% of adults and a higher percentage of children never get), and urges prompt treatment with antibiotics. He says bluntly that holistic or alternative treatment methods don’t work, so waste no time getting the antibiotics. Then you can get on with your life.
Etienne Goyer writes about a growers’ convention in Quebec to build DIY raised bed shapers, cultivators and finishers. This is part of the ADABio Autoconstruction association mission to empower farmers with the skills to build their own machinery. I had looked at their website, but struggled with my high school French, so I am very happy to have this explained in English!
Lastly, Gretel Adams writes about how to set prices for cut flowers, for retail, wholesale, weddings and bouquets.
We’re having a very busy time in the garden. Because of late cold weather followed by too much rain at once, all our transplanting has been delayed. We’re up-to-date in the permanent raised beds – we’ve planted out lots of lettuce, senposai, early cabbage, scallions, our first cucumbers and summer squash, and chard, tomatoes, eggplant, celery and okra. We’re also up-to-date on raised bed sowings of carrots, turnips, beets, snap peas, snow peas, bush beans, edamame and asparagus beans. But in the row-crop areas, it’s a different story. We have planted out our main-crop cabbage and broccoli, our “spring” potatoes and sown our first corn. We’re about a week behind on our big transplantings of Roma paste tomatoes, peppers, melons, sweet potatoes, and therefore watermelons. It’s also time to sow more beans, cucumbers and squash. But we’re getting to it as fast as we can!
We’ve added in late afternoon transplanting shifts, and some random evening weeding (which has helped us get the first round of carrot and beet thinning done). Yesterday I measured and flagged the areas for Roma tomatoes, peppers, melons, beans, edamame, watermelon, and sweet potatoes. I set out the mainline tubing for the drip irrigation and dropped the shuttles of drip-tape at the ends of the patch. I wrote about our drip tape shuttles a while back. They are part of our commitment to minimize our agricultural plastic usage by making our plastic stuff last. The shuttles let us fairly easily reuse the drip tape.
After running out the drip tape, flushing the lines, capping them off and testing (and fixing!) any leaks, next we’ll roll out biodegradable plastic mulch. This wonderful product has changed our lives! And yet we are not all firmly convinced it is an ecological choice. The language in the accessible information can be confusing.
We like using biodegradable plastic because it warms the soil, leading to much earlier crops, it keeps the weeds down for a few months, and then it falls apart, so we don’t have to remove it and add to the heaps of agricultural plastic trash. It’s especially good for vining crops like watermelons and sweet potatoes, because by the time the mulch disintegrates, the vines cover the ground and weeds have little chance. Why we qualify our praise is because it has been hard to find out what it’s made of, and what it disintegrates into. And for some, there’s that knee-jerk reaction to anything plastic!
Biodegradable is not the same as bioplastic, nor as bio-based. Bioplastics are a type of plastic made from biological substances rather than from petroleum products alone. Some are biodegradable, some are not. Wikipedia distinguishes two types of bioplastics 1. Oxo-biodegradable plastics (made partly from natural sources, with non-biological additives) – they break down into biodegradable materials; and 2. Plastics made wholly or in part from vegetable material. The second type are often made of cornstarch or sugarcane, but could be made from other agricultural crops. Some biodegrade, others don’t (eg those made from sugarcane ethanol). I found the Wikipedia explanations confusing and some read as if they were funded by petrodollars: “It is difficult to see why . . . resources . . . should be used to produce them when the raw material for conventional plastics is so inexpensive and is available in unlimited quantities.” Really.
I found a European Factsheet on bioplastics which clears some of the confusion. There are conventional (petroleum-based) plastics and there are bioplastics. Bioplastics may be divided into three categories. The first is the bioplastics which are not biodegradable. The other two are biodegradable, and differ in whether or not they contain fossil-based materials or only bio-based materials. Our goal would be to get biodegradable bio-based materials.
The two most commonly available biodegradable plastic mulches in the US are Eco-One and Bio360 from Canada. Novamont, an Italian company, imports Biotelo, the original mulch film made from their product Mater-Bi.
Eco-One describes itself as Oxo-degradable. It claims “Environmentally sound degradation: Laboratory studies indicate that this degradable plastic breaks down into CO2, H2O and biomass without toxic residues. Degrades fully both above and below the soil.” It’s available clear (for encouraging early emergence of sweet corn) and black, including an extended lifespan version for those wanting a 5-6 month window before it degrades, rather than the usual 3-4 months.
Bio360 is made by Dubois. It’s entirely biodegradable, and made from Mater-Bi, a non-genetically-modified starch with vegetable oil resin. Mater-Bi® is a wide family of fully biodegradable bioplastics, sold in pellet form to the industry of bioplastic converters. Mater-Bi®’s ingredients consist of plant starches, “mainly corn starch, with fully biodegradable aliphatic-aromatic polymers from both renewable raw materials (mainly vegetable oils) and fossil raw materials. Mater-Bi breaks down into carbon dioxide and water, with no mulch residues in the soil.” (see also the Cornell University 2006, Biodegradable Mulch Product Testing). Ah! So even Mater-Bi contains some fossil raw materials. And of course, fossil fuels are used in the manufacturing process. Life is so full of trade-offs!
I found explanation of the chemistry from the Biodegradable Products Institute, as part of a 2012 petition to the USDA National Organic Standards Board to allow “Biodegradable Mulch Film Made From Bioplastics”. The bioplastics they were petitioning for are not polyethylene like regular plastic mulch, but “polyesters, polymers formed by the reaction of a hydroxyl group and a carboxyl group. The natural world is full of ester linkages. Living cells and organisms have developed enzymes to hydrolyze the ester linkage. Examples of natural esters are fats and oils, where three fatty acid molecules are esterified to glycerol/glycerin; natural waxes, where long-chain alcohols are esterified to a fatty acid; and some natural flavors, such as banana flavor, n-amyl acetate, an ester of n-amyl alcohol and acetic acid.” Biodegradable bioplastic mulch film materials can contain carbon black to make the film black to absorb heat from the sun. Or titanium dioxide to create white mulch, which can cool surface soil temperatures slightly, by reflecting most of the sun’s heat.
NatureWorks‟ PLA INGEO, Ecoflex® F Blend C1200, Ecovio® F Film and Ecovio® F Blend, Mirel™, were also listed in the petition as suitable Biodegradable Mulch Films made from bioplastics. In contrast, oxo-biodegradable materials were not included in their petition, because they did not fulfill the two criteria proposed to address the concept of “fully biodegradable plastics”.
The Organic Standards are inconsistent, as §205.206(c)(1) permits “mulching with fully biodegradable materials” but §205.206(c)(6) requires that “plastic or other synthetic mulches . . . are removed from the field at the end of the growing or harvest season.”
I’ve been buying from Nolt’s Produce Supplies in Leola, PA (717) 656-9764. They sell Bio360 BTB645 4′ x 5000′ for $345 plus shipping, and Eco-One E1B548 4′ x 8000′ for $243 plus shipping. They are a company that doesn’t use email or websites, and they’re closed on major Christian holidays, so don’t call then! Johnny’s sells 32′ lengths for $17.95. Robert Marvel sells whole rolls of Eco-One and Bio360 (call for prices).
The first biodegradable plastic we used was Bio-Telo, (Mater-Bi). Since then we have sometimes bought that and sometimes Eco-One. I had not appreciated the difference. Knowing what I know now, I’ll buy the Mater-Bi types in future, rather than the oxo-biodegradable ones.
Next time I’ll write about how we set out biodegradable mulches without he use of any machines. Sorry for the delay in posting. I’m working on making improvements to my website, honest!
The April Growing for Market magazine is out, with my article about mulches. We use a range of mulching materials to help keep down weeds, retain soil moisture and either cool or warm the soil. We use cardboard topped by woodchips or hay for our blueberry plantings,and hay for asparagus. In the past, we used newspaper and hay for strawberries, nowadays we use landscape fabric with holes melted into it. We use hay for garlic, summer-planted potatoes, celery, eggplants, chard, spring broccoli and cabbage. We use the biodegradable plastic (Mater-Bi or Eco One) for watermelons, peppers, cantaloupes, sweet potatoes, and sometimes cucumbers or squash. it helps warm the soil and so the warm-weather crops grow much better and this alone gives us watermelons a month earlier than previously. We also grow our own mulch, a winter cover crop of winter rye, hairy vetch and Austrian winter peas which we mow down in early May. It’s a no-till cover crop – we transplant our Roma paste tomatoes right into the dead mulch. The vetch and peas provide all the nitrogen the tomatoes need, so we don’t need to add any compost. The rye covers the soil for 6-8 weeks. then we unroll hay bales between the rows to last till the end of the long season. No-till mulches keep the soil cooler than if the soil were disked or tilled, so no-till cover crops are only suitable for crops you don’t want quickly!
Other articles this month include one by Andrew Mefford about watering and fertilizing hoophouse tomatoes in Maine, and one by Brett Grohsgal about smoothing the process of making urban CSA deliveries, including an amusing taxonomy of drivers (Dawdlers, Darters/Weavers, Reckless Racers, Breakers, the Distracted, the Erratic, and Smooth Operators. If only we were all Smooth Operators! Brett also includes his tips on choosing the best delivery vehicle, where he comes out in favor of an Isuzu box truck. Ariel Pressman writes part two of a series on finding good workers and the flower grower Gretel Adams tackles managing multiple markets as well as weddings. Everyone is jumping into action for spring!
This week in the garden we have been stymied by excess rain (again). Beasties have been eating our crops. I caught two groundhogs already. they were snacking on our kale. In the process of trapping groundhogs in a live trap, I accidentally caught a skunk. This happened last year. It could even have been the same silly skunk – it had a lot of white and not much black to its fur.
So, how to let the skunk out of the trap without arousing its ire? We brainstormed a bit and I told how I did it last year, using sticks to open the trap and a plastic sack to screen myself. One of the crew came up with a better idea, which I’ll now pass on, in case you ever need to know how to do it. She got a large piece of cloth, draped it over the trap and then delicately opened the trap by hand, through the fabric. It worked like a charm. The skunk ambled out. But then it turned round and went back in, back to sleep. Skunks are nocturnal, so I guess it thought better of setting out to find a new resting place. We left the trap open all night, and in the morning it had gone.
The fabric was so perfect we are now keeping it in the garden shed in case we need it again. It was a large piece of knit polyester – thick, drapeable, washable, and not the sort of thing anyone would have wanted to make clothes out of!
Meanwhile we have a burrowing animal biting off our broccoli seedlings from flats in the coldframe. It isn’t eating them, just felling them, and stashing them in piles. Argh! My current theory is moles. Although carnivores, they apparently use leaves to line their nests. We tried hot pepper on the seedlings, the rain washed it off. We set the flats on landscape fabric. Now they bore through the landscape fabric. The tunnels are too big for voles or mice. Today we are trying to fob them off with dumpstered iceberg lettuce, and spare kale seedlings. If anyone has ideas, please leave a comment.
On Thursday I’m off to Asheville, to the Mother Earth News Fair, where I am giving two presentations, Cold-hardy winter vegetables, and Crop rotations for vegetables and cover crops.
After a week of drizzle, it finally eased up and we started harvesting our sweet potatoes. I wrote a lot about this topic last year, so I won’t go into many details here. As usual, we set the dug roots in clusters, so we could see which plants yielded most and chose medium-sized roots from those to grow our slips next year. In the picture above, we are crating the sweet potatoes after someone has gone through selecting the seed roots. In the right background you can see our grid-linked solar array. In the left background is our hoophouse, and to the left is our dying last sweet corn planting. We have one last picking today, from the Silver Queen at the far end. We used a low electric fence around this patch to keep the raccoons out, and either it worked, or the beasts didn’t notice this planting. We didn’t get any visits from tigers or elephants either! Also visible in the photo above are remaining bits of the bioplastic biodegradable mulch we used. It’s made from non-GMO corn, and is great for warm-weather loving vining crops.
This year, the Georgia Jet seem more productive than the Beauregard – I think that’s usual. We dug about a third of the crop the first day and got 86 boxes. The second day we had a lot of other harvesting (beans and broccoli being the most time-consuming), so we only dug another 36 boxes. We’re still only 45% of the way down the patch, so we could end up with 250 or more boxes. Probably the yield will taper off closer to the end of the field as the deer were browsing on the vines all summer.
Friday update: Well, we finished harvesting yesterday, and the yield dropped off a lot where the deer had been browsing (memo: fence out the deer in future!) We got a total of 177 boxes of various sizes, perhaps about 3939 pounds, almost two tons. That’s not a record-breaker, but is second best in the past ten years.
Our yearly harvest of sweet potatoes has varied a lot, from 31 boxes (a sad year) to 243 in 2009. An average over ten years of 112 boxes, each weighing perhaps 23 pounds. We grow about 800 row feet. We always hope to have enough to last till the beginning of May, when people start to lose interest in sweet potatoes, and start hoping for tomatoes.
Now I’ve glided smoothly into the statistics section of this post, so I’ll tell you some figures for my book sales while I’m at it. New Society has sold 3320 to mid-September, from a 5000 print run. They say the book is selling well, not many returns. At Twin Oaks we’ve sold 150 of the 250 we bought in February when it came out. I’ve just set up an Author Page at Amazon, so I can tell you they have sold 940 print copies up till 10/6. They also provide me with ranking info (this could get addictive if I let it!) and my book was #40,116 when I looked. That sounds pathetic till you realize that’s out of 8 million titles. Anyway, enough vanity! As far as its usefulness to readers, having an Author Page means that if you go to Amazon, to my book page, and then click on my name, you can read my bio, and see my upcoming events, and get back to this blog.
Getting perspective on the bookselling world, I was encouraged to learn that there is being a resurgence of small booksellers, despite the Big Online One. Here’s a link to the story in the Christian Science Monitor in March this year. I learned about it from Wendy Welch of the Little Bookstore at Big Stone Gap, who I met at the Festival of the Book in Charlottesville. She has written a memoir about her bookstore, called The Little Bookstore of Big Stone Gap, which you can buy via her website, or, I’m sure, at her store.
And now on to this Inspiring story: At the Mother Earth News Fair I met a young woman of 12 who had borrowed my book from her library. She got inspired and decided to start market gardening. She succeeded in clearing $6000 in her first year, when she was 11!
What a week! With the forecast for low temperatures on Sunday and Monday nights this past week, we back-pedaled on our transplanting plans. The tomato plants in our coldframe were very tall. In order to cover them we extended the cold-frame height by balancing plastic crates on top of the blockwork walls. Setting the lids on top of this construction was a bit precarious, but it worked well. Only a few of the taller tomatoes got nipped at the very top on Monday night when the temperature plummeted to 30F. 5/14 is very late for a last frost for us. Our average for the past ten years is 4/30, but in 2009 it was 5/19. In 2011 it was 4/14. Farming is full of surprises!
On Tuesday we started transplanting tomatoes. Hot dry windy weather. On Wednesday 5/15 it reached 90F. On Thursday afternoon we planned to continue the big transplanting of our Roma paste tomatoes. Three rows are in mowed no-till rye, vetch and winter peas cover crop and one row is on black biodegradable plastic mulch. (Here’s an interesting link to a comparison of the two biggest brands of biodegradable plastic mulch. http://extension.udel.edu/ag/files/2012/03/2012DegradableMulchWM.pdf) But Thursday’s shift was inauspicious. We started with only 5 of us (we plan for 7). One person had to leave at 4pm. One person was called away to bale hay. Another person agreed to provide childcare for the person baling hay, from 4-6pm. Then another person started to feel ill, and left the scene. The 3 of us still working at 3pm started to sow our second zucchini and summer squash. We each used two dowels to make holes every 6″ in the biodegradable plastic mulch. We got the holes popped through, but then another community member cycled by and warned us of a strong thunderstorm heading right for us. Discretion being the better part of valor, we retired for a tea-break and to consult the local radar on Wunderground. An intense “red and yellow” storm, not very wide (ie not very long-lasting), was due any minute. Once it started to rain we decided to quit trying to garden for the day. good thing too. We got an inch of rain in an hour. Too bad the soil hadn’t dried out enough for us to do a second hilling of the potatoes before this new rain. or make ridges for sweet potatoes. Now we’ll have to wait another week, during which there is 20-80% chance of some rain every day except Monday, when it is forecast to be foggy. So I’m getting closer to finishing reading my library book. . .
Meanwhile, in the Mental Gardening Department, I found I had made mistakes in my Growing for Market articles on parsnips and fennel, about which plants can cross-pollinate each other. So I wrote an apology and correction. One of these mistakes is in my book. In case you are reading my former, deluded, beliefs, here is the correction: On parsnips, the facts are that parsnips can cross with wild parsnip, but not with carrots or Queen Anne’s Lace, as I wrongly claimed.
On fennel, the facts are that fennel does not cross with anything except other fennel. It is widely said (even by some seed companies!) that dill and fennel cross, and some even describe the terrible flavor of the resulting crosses. Clearly this is a superstitious belief that continues because acting on the belief produces good fennel (or dill) seed. Similar to how someone might snap their fingers to keep away tigers – no tigers – complete success! I’ve long believed dill and fennel crossed. It’s good to know I don’t need to worry about that any more.
This is the first error I’ve found in my book. Soon New Society wants a list of corrections from me, for when they do a reprint. I’ve only found this and one formatting glitch so far. Embarrassing, but I repeat my Mantra for Consolation: “The only people who never make mistakes are those who don’t do anything.” On Monday I did an interview for Lightly on the Ground Radio on wrir.org (Richmond Independent Radio) with Sunny Gardener. I’m learning how to find and download the podcast (so many technical skills to learn!) I’m working on a powerpoint presentation on Planning Fall Vegetable Production, for Virginia State University’s Summer Vegetable and Berry Field Day on June 27 at Randolph Farm. This will lead nicely to my Last Chance Sowings article for the August Growing for Market and a Cold-Hardy Winter Vegetables presentation for the Mother Earth News Fair in September
Here’s my list of upcoming presentations and workshops:
June 27 VSU Randolph Farm. Planning Fall Vegetable Production