Our hoophouse on solarizing day, August 5. Note we kept the big shadecloth over the roof until we had done the work of installing the plastic over the soil. Photo Ken Bezilla
Solarization Benefits We Hope For
I wrote Solarization of Our Whole Hoophouse on 8/12/26. This summer we decided to solarize the whole hoophouse. We hope to reduce fungal diseases in our winter crops, draw down the weed seed bank, and kill lots of nematodes. We planned to solarize for the whole of August (4 weeks). We started that on August 5, and solarized until September 3, a full 4 weeks later.
A One-Month Break from Usual Hoophouse Work
It was a nice break to do nothing in the hoophouse for a month except run the drip irrigation twice a week. We left the drip tape in place so we could water the soil and keep it alive below the hot zone. It was an unearthly sight to just have a sea of plastic in there, and one of the crew popping in there to turn on the irrigation reported that to was quite surreal to walk barefoot on the hot plastic.
We agreed to use the time to do some infrastructure repairs, and did get a new window made and the other one repaired.
We repaired our big all-encompassing shadecloth and reset the grommets to be a better fit with the spacing of the hooks in the baseboards.
We researched horizontal airflow fans to replace our hippy-rigged box fans, but we balked at the $1000 price tag. Maybe EQIP grants would help?
We did our crop planning for the winter and made a map. We cross-checked the schedule against the map and made sure everything fit. We did some perimeter weeding and laid down landscape fabric.
A Bad Choice Narrowly Avoided
We had the notion that if we had thought of it in time, we might have spread mature compost on the beds before spreading the plastic and killed the weed seeds that landed on the compost pile while we ignored it all summer. We got behind with the mowing, and we know grass and spiny amaranth seeded somewhat on to the pile. Fortunately, we didn’t do that! Sterilized compost has most of its microorganisms killed! Instead, we re-composted the weed-seed-infested pile and got a new pile in the meantime.
Hoophouse soil thermometer showing 100F (38C). Photo Ken Bezilla
De-Solarizing Day
On de-solarizing day we allowed a little lead time (not enough!) to disperse some of the 120F (49C) heat by flinging open the doors and windows. The soil temperature was 100F (38C). The peak air temperature during the month may have reached 140F (60C) although no one wanted to linger in there long enough to really study the thermometer. It had been 80F (27C) before we solarized and is back down to that temperature in as I write this in late September.
Normally we leave the big shadecloth in place over the whole hoophouse until mid-September or so, but this year we wanted maximum heating for the solarization, so we removed it a couple of days after solarizing (when it stopped raining).
We had bought 32’x100’ (9.7×30.5m) plastic which was just right for the footprint of our 30’x 96’ (9 x 29m) gothic hoophouse. We unrolled it down the center bed (it was folded in several concertina folds from each edge to the middle). We mimicked that kind of folding to pack it away.
The first step of removing the hoophouse solarizing plastic: folding the edges to the middle. Photo Ken Bezilla
We started by removing the buckets of rocks we had set round the edges to hold the plastic down. Next we folded both sides to meet in the middle. We got old towels to wipe the underside of the plastic dry. We used some of the drying time to teach broadforking and cultivation and raking to new crew members. We noticed how warm the soil was to our hands.
Wiping the solarizing plastic dry between folds. Photo Ken Bezilla
Next we brought the outer folds in to meet in the middle again, and repeated the mopping operation. Later we thought a sponge mop might have been a useful tool. We used more drying time to start to return things we had stored in a shed during Solarization Month.
Removing hoophouse solarizing plastic: second fold of edges to the middle. Photo Ken Bezilla
We repeated the folding until a simple folding in half made a sensible size for rolling, and ended up with a fat roll of plastic tied up with rope. We wrote on it to deter anyone who might think of using that plastic for any other purpose.
The last fold of the the hoophouse solarizing plastic, making it ready to roll once dried. The dried stems are from a buckwheat cover crop we covered with the plastic. Photo Ken Bezilla.
Disadvantages of Solarizing
I was sad to say goodbye to the hoophouse bell peppers as they were the best we’ve had in years. Usually we keep the peppers until October and do our winter crop planning so that the pepper area is the last planted in winter crops, but we made that sacrifice! For several years our peppers didn’t do well, as the salinity of our soil had got too high. We now do salt wash-downs in September and March. This year the peppers were spectacular! Big plants, huge peppers! Rather disappointing to have to pull them at the beginning of August.
Bullnose pepper in our hoophouse June 27. Photo Alexis Yamashita
Several days into the solarizing I realized with dismay that we had killed off all our zipper spiders and probably their egg cases. The spider corpses were still attached to the framework. Zipper spiders seem to be homebodies. Surely they could have found a way to leave? But mostly they do die at the end of summer, just not on open display. In recent years we have not had any of these spiders outdoors, but many in the hoophouse. They do good work consuming the insects they trap.
Zipper spider on the pepper plants in our hoophouse on September 10 a previous year. Photo Pam DawlingZipper spider egg cases hanging from the hoophouse plastic. Photo Wren Vile
One big disadvantage of our choice was that the work of bed prep and planting in there after de-solarizing was dreadful! We had hot sunny weather, and the allocation of each day’s prep work took 3 hours or more. By lunchtime it was 120F (49C) in there on many days. Exhausting work! But it didn’t seem worth putting the big shadecloth back in place as we normally remove it around September 20.
Hoophouse fall bed prep. Broadforking in plastic sandals is not recommended! Photo Ken Bezilla
Apart from the workers suffering the effects of the heat, the soil also dried out a lot faster, and we had to keep working (no rest!) to break up the big lumps of soil before they became bricks.
We prepped one bed and got ready to sow. We decided to use wire hoops and a 6’ (2m) roll of shadecloth like we do outdoors for lettuce in hot weather. That worked well, although the bed edges did dry out fast, maybe because the paths were still holding heat from the solarizing. So we had to handwater the bed edges daily for a week or so.
Spinach seedlings from pre-sprouted seed in the hoophouse in September. Photo Pam Dawling
One of the first crops we sow is spinach, using seed pre-sprouted in the fridge for 6 days. No way would it have germinated in that hot hoophouse soil! On sowing day, the spinach seed showed little sign of sprouting, but we sowed, watered well, shaded it, and it came up great! The extra attention paid off. This spinach will feed us all winter until about March, as we just harvest leaves. By September 21, all the early crops in that bed had emerged (scallions, Bulls Blood beets, tatsoi, radishes as well as the spinach). We needed to remove the shadecloth from the bed once everything had emerged, so the seedlings didn’t get leggy. 12 hours of daylight isn’t so much.
The perennial weeds growing in under the baseboards did not die. Once we removed the plastic the wiregrass (Bermuda grass) raced across the edge bed and started colonizing the next bed. Fortunately juvenile wiregrass is relatively easy to pull up.
De-solarizing our hoophouse. Note the vigorous wiregrass along the south baseboard. Photo Ken Bezilla
Most years we grow summer cover crops in the hoophouse, thus keeping the soil-life active and adding organic matter. This summer offered no gain of organic matter, which I do regret.
Advantages of Solarizing
We have sowed an outdoor seedbed with things to transplant into the hoophouse in October when we have more beds prepared. Work is progressing well, although we’ve had to scramble some days to stay on track. Because using transplants from outdoors is part of our usual plan, we did not have to make any changes to the beds after the first one, om account of high temperatures.
The advantages of solarizing will become apparent in the next 6 months. Two weeks after uncovering the soil we did find a tiny tomato seedling, but the seed could have been dropped from our clothes after the solarizing month, rather than being a survivor. It was interesting to see it.
For myself, I’m unsure if I’d want to do this again. The advantages are going to have to be huge – like no more nematodes. I’ll write more as the next year unfolds.
Solarization plastic spread across our hoophouse. Next we weighted down the edges with small buckets of rocks. Photo Ken Bezilla
I wrote in August 2019 about Solarization and Crop Choices to Fight Nematodes. Previously we solarized part of a bed in our hoophouse, or one or two beds. I’ve written before about our first efforts at solarization to fight root knot nematodes in our hoophouse. Back then we shoveled soil on the plastic edges to make a good seal between the plastic and the soil. Later we developed a good technique of pushing the plastic edges down into soil using spades, which gives a much better seal, and if you work both sides of the bed at the same time you can avoid wrinkles.
Solarizing a single bed in 2019 using a spade to push the plastic edge into the soil.. Photo Pam Dawling
This summer we decided to solarize the whole hoophouse. We hope to make progress on reducing fungal diseases in our winter crops, drawing down the weed seed bank, and killing lots of nematodes. We plan to solarize for the whole of August (4 weeks). Here’s the story so far.
Solarization
Solarization is a method of killing pests, diseases and weed seeds near the surface of the soil by covering the soil with clear plastic in hot weather. Nematodes are only active in warm weather, and we have not had problems with them outdoors, but of course, it’s warmer in the hoophouse!
“Solarization uses clear plastic (old hoophouse plastic is ideal). In a summer hoophouse, solarization can be as quick as 24 hours, Andrew says. When we’ve done this, one of our goals was to kill nematodes and fungal diseases, not just weeds, so we waited a few weeks. Outdoors it takes several weeks. You can see when the weeds are dead. Bryan O’Hara poked a thermometer probe through solarization plastic and found a 50F degree (28C) difference between the outside air and the soil immediately under the plastic; a 10F (6C) difference at 1″(2.5 cm) deep and little temperature gain lower than that. Solarization does not kill all the soil life!”
Preparation for Solarizing
Last time we changed the plastic, we saved our old hoophouse plastic in one large sheet, for just this option of solarizing the whole hoophouse. Unfortunately, someone used it for some other purpose, and we ended up having to buy new plastic to carry out our plan. Ouch! Label your old plastic very thoroughly! We bought 4 mil Tufflite Nursery Clear plastic from Nolts Greenhouse Supplies, Ephrata, PA (only rated for one year outdoors), thinner than the 6mil we buy for covering the frame. Be aware that shipping can be a big part of the cost, unless you are ordering lots of things.
We pulled up our tomatoes and cucumbers at the end of July, a week earlier than usual. The squash had already gone. I was sad to say goodbye to the bell peppers as they were the best we’ve had in years. Usually we keep the peppers until October and do our winter crop planning so that the pepper area is the last planted in winter crops, but we made that sacrifice! For several years our peppers didn’t do well, as the salinity of our soil had got too high. We now do salt wash-downs in September and March. This year they were spectacular! Big plants, huge peppers!
Lady Bell peppers ripening on 7 July. Photo Pam Dawling
We decided to keep the big shadecloth in place for the solarizing day, expecting it to be very hot. It wasn’t, but it was a wise precaution. We planned to remove the shadecloth the next day, but it was raining and we need the shadecloth to be dry to pack it away. So we waited a couple of days for our little monsoon season to pass. Normally we leave the shadecloth in place until mid-September or so, but this year we want maximum heating for the solarization.
We are leaving the drip tape in place so we can water the soil and keep it alive below the hot zone. If we had thought of it in time, we might have spread compost on the beds before spreading the plastic and killed the weed seeds that have landed on the compost pile while we ignored it since early April. We were stretched thin and got behind with the mowing, and we know grass and spiny amaranth seeded somewhat on to the pile. We did have it partly covered with a tarp.
Unrolling the Plastic
Unrolling plastic to solarize the hoophouse. Photo Pam Dawling
We bought plastic 32’x100’ which was just right for the footprint of our 30’x 96’ gothic hoophouse. We unrolled it down the center bed (it was folded in several concertina folds from each edge to the middle). We gradually unpacked the folds and pulled the plastic out to the edges. It is important to get as smooth and tight a fit as possible (few airgaps between soil and plastic).
We designated one person to take their sandals off and walk on top of the plastic, while the rest of us gathered small buckets and put some rocks in them, to anchor the edges. This all went very smoothly and took less time than we expected. We used about one bucket of rocks every 20’ down the length. We rolled our painters’ pole that we use for our SnoBrum in the plastic across the west doorway, the direction the strongest winds come from, for add extra security in preventing wind getting under that edge of the plastic. We did not bury the plastic edges in the soil, as that seemed difficult and we figured a large area would suffer less edge cooling/heat escape than a single bed.
Closing Up the Hoophouse for a Month
We closed the doors and windows and relaxed into enjoying a summer month off from harvesting in the hoophouse. We have made a list of infrastructure repairs, landscape care and, of course, the winter crop planning to do in t he next month. And we’ll be irrigating maybe twice a week and checking the soil thermometer periodically. It showed 80F last week, before we solarized.
Hoophouse solarization at Dripping Springs Garden, Arkansas. Photo Pam Dawling
I’ve written here before about our struggles with root knot nematodes in our hoophouse, and you can read everything I know about nematodes in the Year-Round Hoophouse.
My article on nematodes in Growing for Market in November 2014 describes our discovery of the beasties and our first attempts to deal with them. My most thorough blogpost about nematodes was for Mother Earth News Managing Nematodes in the Hoophouse. It’s free for MEN members.
There is info on dealing with nematodes from Garry Ross in Hawaii, where nematodes are a fact of daily life, in my post Cold weather, snow, thinking about nematodes from February 2015.
“This month’s recommendation points to a short film rather than a book. It portrays the life of Helene, a farmer who cares for her land on the west coast of Norway.
To me this story represents all that is good in this world. A deep sense of connection and rootedness to the land, a love for traditional skills and creation of things that are both useful and beautiful, an appreciation for natural materials, the respectful interaction with animals, the care of one’s belongings ensuring their longevity, supporting people in finding their place in the natural environment…
Among many others, one of the messages that really stuck was that the effort of each and one of us to make a difference in this world matters. It has value, irrespective of how seemingly small it might seem in the moment and that is such an encouraging thought to carry along through life.”
24 Hours on a 200 Year Old Norwegian Farm (a video everyone should watch)
This is Helene Olli. I just want to add, that the people Hunter call[s] “farm hands” is [are] WWOOFers and other volunteers. I have been a host for WWOOF Norway since 2015. I have had so much help from fantastic people from around the world th[ese] summers, also some winters. I really, really want to give them credit for helping me [with] building the farm, and also running it. My policy is this: if you stay in Gripen, helping with the farm, it gets a little bit yours. I have a lot of returning volunteers, and I feel I have a much bigger family because of this. I am so happy and thankful that they want to stay and contribute. I wish that could have been more visible in the video, but I am saying it now. I am so blessed, having so much good people around!
LynBreck COURSES – Limited availability left for 2026
Lynbreck BOOK. Our Wild Farming Life: Adventures on a Scottish Highland Croft. I have reviewed their book Our Wild Farming Life.
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Aurin Fertilizer: an ancient fertilizer returns to use
On a completely different topic, linked to the one above by the desire and practice of living lightly on the earth, here is information about Aurin, a fertilizer from VunaNexus, that is approved for use in France and Switzerland. Not available in the US, so you’ll have to make your own. I wrote about urine fertilizer Here.
Bottle of Aurin Fertilizer
The VunaNexus company say they are recovering minerals, similarly to what is commonly done to recover minerals from used electronics. They supply urine-diverting toilets which send the urine (without diluting it with water) into a small treatment plant in the basement of the building. The treatment plant first removes pollutants such as antibiotics, hormones, and drug residues, then concentrates the nutrients such as nitrogen and phosphorus while pasteurizing the liquid at 90C (194F) to kill potential viruses and other pathogens. Pure water is distilled out of the liquid and returned to the flushing system. This leaves Aurin, the liquid fertilizer, sold in 0.5 L (1 quart) recyclable PET bottles, as well as 5 L (1.3 US gallons), and 10L (2.6 US gallons) jerricans.
Label of Aurin fertilizer
Their urine-diverting toilets are used by the European Space Agency in Paris and the fertilizer is being tested by city authorities in Paris, Lausanne and Zurich. Any lingering prejudice that this is just a hippy idea is fading fast in these days of fertilizer supply chain disruptions in the Strait of Hormuz. The UN says 45 million people are at risk of acute hunger because the conflicts in the Middle East have increased fertilizer prices. We don’t need petroleum-based fertilizers as long as we have urine!
The chief executive of VunaNexus says that if we recycle all the human urine in Europe, we could provide 30% of the nitrogen needs of their farms, provide a more sustainable option to water treatment systems, and reduce the environmental impact of petroleum fertilizers.
Aurin in large-scale agricultural use. Photo VunaNexus
Front cover of Ben Falk’s book, The Resilient Farm and Homestead, revised edition. Chelsea Green
Book Review: The Resilient Farm and Homestead: 20 Years of Permaculture and Whole Systems Design. Ben Falk. Chelsea Green. Revised and Expanded Edition, 2024. 342 pages, $44.95 US, 40G BP.
Ten years after writing the first edition of his book, Ben Falk has made a revised and expanded edition with new information on greenhouse design, agroforestry, silvopasture, beekeeping, human health and more. Even more valuable are his further ten years of experience feeding his thoughts and practice of permaculture in a cold Vermont climate, no-till farming, native versus introduced plants and insects, vegan versus livestock-included farming, dealing with climate change and living a whole life. He was a single, physically fit, energetic and slightly idealistic, 25-year-old when he landed on his 10-acre homestead in 2003, and 35 when he wrote his first book, encouraging readers to “Be bold and try stuff.” After another ten years, he has a partner and a son, a lot of lived experience with various agricultural theories, a realization that his first decade was the “establishment phase,” a career in professional land use design, and determination to live a balanced life. His gained wisdom shines through.
Ben has the courage to tackle his earlier ideas and those of other agricultural writers and speakers and say what did not work for him and what does. You can be confident that his suggestions are practical and efficient, as well as resilient. The beautiful photos show ideas in action, not merely under construction as some permaculture publications do. Rice paddies in Vermont, possible but sensible? Swale-enclosed ponds, lovely.
The book includes chapters on creating a legacy in a time of change, design and site establishment, water and earthworks, fertility harvesting and cycling, food crops, adaptive fuel and shelter, resilience and regeneration for the long haul. There are useful appendices, including an aptitude quiz on living a resilient lifestyle, a skill list for emergencies, a curriculum for a resilient homestead, a checklist of tools and materials, a vulnerability checklist, and a glossary, a resource list, chapter notes and a thorough index. The introduction lists 20 new ingredients in this revised edition (including a list of 30 common cold climate site design and building mistakes); 16 practices they have stopped since his first book (spraying compost tea takes too much time and shows little result); and 10 new practices they have adopted (grazing cows).
Farming and ecological living can appeal to people across the political spectrum, but Ben does not shy away from briefly mentioning the current threats of economic, social and environmental collapse, while addressing vulnerabilities and how we might respond. This is not a “doom-reading” book, but an encouraging and very practical one! “If we steer Earth towards adaptive regeneration, we’ll see true resilience much sooner than by just letting it develop ‘naturally’.”
This book uses permaculture design and its framework for problem-solving and refers to numeric zones within a location. This is concisely explained, so don’t let the word deter you if you are new to permaculture. Ben Falk has not unquestioningly adopted that cause, or the Green Dream (personal ecological consumerism regardless of lack of fundamental political change) but thoughtfully tested and applied ideas that work and don’t cause problems elsewhere in the world. Ben advocates for people becoming producers rather than merely “less-bad “consumers.
The chapter on design and site establishment is best read before you decide which piece of land to buy. This is the time to consider your mission, goals, analysis of what’s possible, and how you plan to do that. To make your land use design, analyze what’s available, consider your options and implement your decisions, (aka think-design-do-reflect-redesign) as many times in a repeating cycle as you need to. Likely you’ll have more ideas for tweaking the system than you have energy for, so you’ll need to prioritize the adjustments that will have the most effect. This ensures maximum regeneration of land for minimum energy and time input. Ben lists his top five leverage points: swale construction and use, grazing animals, broadcasting seed and transplanting, cutting and clearing trees, scraping and tillage to create bare soil.
We need crops that convert the most sunshine and rainfall into usable food. More nut trees, for example, and intensive rotational grazing. Much of the cold-temperate climate landscape would be most productive converted to permanent silvopasture. Sometimes fossil fuel use to develop a site sooner is very worthwhile. Examples include chain saws, earthmovers, electric power tools.
Resilience is the ability of a system to recover from disturbances. Factors include Diversity, Redundancy, Connectivity and Manageability. Efficiency is not the same as Resiliency. The “whole world” picture needs to be included, and adapting to changing conditions must be built in. Actions that increase both biodiversity and biomass increase the ability to be regenerative.
No single design works for all sites or all groups of people. Your own skills and aptitudes are your most dependable asset. Practice welcoming adversity (the blessing of disillusionment), as a chance to learn and grow stronger. Try to avoid tight attachments to your goals, as this can lead to big struggles. Check out popular notions that others have already found faulty: planting marginally-hardy perennial plants beside bodies of water does not keep them warmer in winter! Your climate is not the same as information from ten years ago would have you believe! Keep your own weather records. Likewise, observe whether some practices you don’t believe in – dowsing for example – do in fact work. Modify your design to balance theoretical “best” practice with practicality: perfectly on-contour plantings do slow, spread and sink water best, but they make mowing and harvesting harder.
Once you have your land, assess it in some detail before taking any firm direction. Work with the realities of your land, rather than planning to radically change them. You may see a better plan emerging. Good designs incorporate the ability to change. Using modular designs makes this easier. For example, consistent bed and path sizes.
Overview of Ben Falk’s homestead. Photo from his website, https://www.wholesystemsdesign.com/
Swales are on-contour ridges made by ditching along contours and piling the soil below the ditch, helping even out the water supply and retaining water that would have run off the surface as much as 20ft downhill. Swales make great places to plant hedges, and the space between one swale and the next makes a good small paddock for intensive rotational grazing.
Only the importation of fertility from other parts of the world has enabled chemical farming to continue after the Great Soil Erosion of the nineteenth and twentieth centuries. When this becomes no longer tenable, will we turn to regenerative farming, or let society collapse? We can save farming by building and conserving topsoil.
When we make compost we need to investigate the source and the content of the materials: What feedstock was given to the Organic livestock that provides the manure? Was it from lab rats with a diet of antibiotics or worse? Grasses take up PFAS, such as those in flexible plastic sheeting. But if not contaminated, they can be a key nitrogen resource. Are roadside leaves safe? Pond weeds, comfrey, burlap bags, cover crops and organic mulches all have their advocates, Human urine benefits plants. Humanure is possible if the household doesn’t use pharmaceutical drugs. Biochar can increase soil water retention, reduce nutrient leaching and encourage diverse micro-organisms, but poorly made biochar can stunt plant growth spectacularly.
Wood chips are great, but wood chippers are expensive to own and operate and a pain to use. (One colleague said to me, “Lots of money, lots of noise, lots of gasoline, lots of time, lots of logs and branches. Small pile of chips.”)
Remineralization is the replacement of missing or deficient minerals, which could be factors limiting crop health. The Soil Food Web is an approach that focuses on soil biological activity as the main limiting factor in crop health.
Livestock has an important role for resilient homesteads. Regenerative high density stocking with very short periods of grazing in each paddock (called intensive tall-grass grazing or mob stocking ) is very productive and builds soil. Tall grasses (having deep roots) are grazed down to within a foot of the ground (not all the way down). Some roots die back once they are no longer needed. As the tops quickly grow back, more roots grow, and soils build. Active management produces much healthier soil than neglect does. Anyone wanting to restore a neglected field area can read what not to do, and what to do, in this chapter. Ben’s approach included sheep, prescribed burns, scything, and over-seeding for several years. But no tilling or plowing.
There are benefits to mowing in some circumstances, with correct timing and severity. Stem density increases and grasses are promoted. If the existing plants have been cut down enough by grazers or machinery, May and June are the windows for lightly reseeding. Never let a field lie fallow for more than a year. Water management will help reclamation. Mow early and often.
Consider permanent fencing. Plan tree plantings in straight rows to make fencing and mowing easy. Refrain from pruning off lower branches if you plan to have livestock, as that will deter browsing. Feed hay to cattle on pasture if needed. If you don’t want to raise animals, you need to mulch or mow the understory of your trees and perennial vegetables. Those tasks take a lot more labor than raising livestock.
Ducks and chickens, sheep and cows all have their niche. Ben found sheep to be more work than cows, and both to be quite an emotional and logistical commitment. Sheep are prone to many diseases, but have a role as smaller, short-term livestock, practical on a smaller homestead. Ducks eat slugs, forage actively, are cold-hardy and have low health maintenance needs. They are good layers, and good mothers, have good predator-awareness, and generally won’t fly away.
Don’t believe all the generalizations you might hear about livestock, species, varieties or even individual animals. Ben reports that his ducks never ate mature vegetation during the growing season, for 3 years. In year 4 they attacked the cabbages. Who knows why? It was a dry, relatively slugless summer, which might have contributed. Observe what is true of your animals this year, but don’t depend on the same thing happening next year. Do believe that chickens will scratch up your seedlings and new transplants!
Keyline plowing is favored by many permaculturists. It was developed in the drylands of eastern Australia and may not translate to moister climates. It doesn’t work well in New England, for example. It may be useful in cold climates (where weather and soil conditions combine to move water across the soil, rather than into it) if drought conditions prevail. Managed small ephemeral ponds can capture and hold heavy rainfall.
Ponds at Ben Falk’s homestead. Photo from his website, https://www.wholesystemsdesign.com/.
In-ground septic systems have leach fields capable of supporting good crop yields, of either cover crops or food crops. Plants cannot move bacteria or other organic pathogens through their tissues, so there is no danger of E. coli in tomatoes grown above your leach field. Plants can, however, bioaccumulate heavy metals and other inorganic compounds. If in doubt, test the plants. Research 2020-2023 suggests plants tend to accumulate PFAs as well as toxins in their vegetative parts, rather than their fruits and seeds.
Chapter 5 moves us on to details of food crops. Long ago, Polynesians navigated the Pacific in their canoes, locating small pieces of land to settle. They took with them 24 special “canoe plants”. These included foods, medicines, fiber and dye plants, building materials and ceremonial plants. They carried plants gathered from a wide area of the world, to adapt to many situations.
Alongside the benefits of perennial crops, there are some disadvantages. Climate weirdness brings changes to frost dates that kill blossoms and pollinators, and can affect chilling hours and flowering dates. One harvest per year from the space the crop occupies can be less than short term multi-cropping annuals provide. Establishment of perennials can take years (so grow some annuals around new perennials for the first few years).
People with short growing seasons would do well to grow lots of storage crops, and all of us are advised to grow a wide range of diverse crops. The book has tables of perennial crops best suited to various extremes of weather, Goldilocks crops to try out on a small scale, if at all, and those that give high yields.
For simplicity, focus on larger quantities of more-reliable long-storing foods rather than lots of small-quantity foods (but keep that crop diversity in mind!). Although Ben’s family used to grow paddy rice, they no longer do so, due to challenges of aquatic weeds, and losses to birds. Especially focus on summer-planted late fall harvests, to preserve food for the Hungry Gap from March to whenever it warms up enough to produce spring harvests. Another option is fermented storable foods like krauts and kimchi, which take less work than canning.
Ben Falk, author of The Resilient Farm and Homestead. Credit Marcia Falk.
Ben has a very interesting essay on “Native to When? “Invasive” Species, Species-ism, and Optimization” that really got me thinking. Healthy ecosystems include high diversity. Humans are part of the ecosystem (not kings or tyrants, but participants). We intend to manage our gardens and farmland in a responsible right-action kind of way. Not merely sit back admiring the view while elsewhere forests are razed to grow soybeans to feed us and our livestock.
Permaculture views plants and other organisms that have been in place for 10 or 100 or 300 years as not fundamentally more natural or proper than recent arrivals. More important is to consider what the plant does and how it affects the soil and other organisms, and our needs in that space. Plants, animals and other humans are not regarded as evil aliens.
Permaculture seeks inclusion and synergy, with adaptation to challenges that arise. This includes a high level of biodiversity, embracing the legacy of food systems from across the globe. It is not modeled on what the ecosystem looked like on the North American landmass in 1491, or before native peoples managed the land to promote chestnut and oak forests, or before mass migrations of buffalo or any other date.
Some conservationists seem perversely focused on getting back to specific species and ecosystem arrangements from an idealized past time, even if this involves large inputs of fossil fuels, chemicals, labor and money.
We are unwise to adopt a “Nativist War-on-Alien-Invader” ideology. During the time that humans have been moving around the Earth, we have moved around plants and animals (and associated microbes). What year could be chosen as a starting point to determine whether a plant is native or alien? We have potatoes from South America, corn from Mesoamerica, honeybees and earthworms from Europe, apples from Southwest Asia, and much more. Choosing European contact as a starting date is a prejudice that ignores previous centuries of land management.
No living thing is permanent. Plant successions and ecosystem change are natural. Native white pine and goldenrod have forced out numerous species across New England. A human moving a plant from one area to another is no more unnatural than a bird moving seeds. Movement of species is part of biodiversity. It is our responsibility to determine if it would be helpful to redistribute a particular species, considering the needs of other humans and other forms of life.
Ben says (and I strongly agree) “Feeding oneself from a monoculture in Iowa or Mexico while devoting time to spraying Japanese knotweed with toxic chemicals will not get us where we need to be.” Attempting to maintain the world around us in a static condition is simply not an option. We now need to provide for 8 billion humans. Hunting and gathering is no longer viable for most. We cannot live as people did when the Earth was more thinly populated.
Worries about invasive alien species may also indicate a fear that nature will “take over”, and even a belief that humans are separate from nature, perhaps its masters, a very colonial concept.
The urgent ecological and social issues in front of us require unified solutions. Fragmented approaches, including wars on specific plants (and cultures), have rarely, if ever, worked. Species eradication and similar fear-based hyper-controlling and divisive efforts fail even as they line the pockets of Monsanto. Treating all life-forms with respect leads us to more understanding, with prospects for synergy. Why, oh why, do the Acknowledgements list 16 men, while Ben’s wife Erica Koch is one of only four named female family members? Let’s have more biodiversity and inclusion!
Chapter 6 covers adaptive fuel and shelter, well worth reading, but one on which I took few notes. It includes house design and construction, fuel for heating and for power equipment, tips on common mistakes to avoid. Chapter 7 is on resilience and regeneration for the long haul, including intergenerational success, children on the homestead, and more.
The whole book is thoroughly researched, clearly written, and will be tremendously useful to all who use it. For more, see Ben’s website https://www.wholesystemsdesign.com/
Why we Wrote a Twin Oaks Sustainable Agriculture Pledge
Roma paste tomatoes that suffered drift of herbicide in hot weather. Photo Twin Oaks Community
One summer, after herbicide drifted in very hot weather into our patch of Roma tomatoes and damaged them noticeably, we gardeners got together with other managers of our other agricultural areas, to find common ground, and avoid causing problems for each other in future. We share our land, and generally our approach to sustainable agriculture. Getting it formally agreed and put into writing was a good idea.
The Twin Oaks Sustainable Agriculture Pledge is a joint policy statement from all the Agricultural Areas about how we farm here, putting in place some kind of standards and a code of practice that we can all adhere to. Each Area may supplement this Pledge with a statement about its own particular practices, which may vary from those of other areas (eg if it becomes feasible to get organically grown grain for Poultry but it’s still prohibitively expensive for Dairy to do the same, then we can have that difference). The goal is not to make us all have to do the same, or make us 100% Organic.
The Principles behind the Twin Oaks Sustainable Agriculture Pledge
To produce food of high nutritional quality in sufficient quantity to feed the community as much as possible with our home-produced foods, for as much of the year as possible.
To promote and sustain Twin Oaks as a healthy rural community and to foster an ethic of land stewardship among our members.
To encourage and enhance healthy ecosystems within the farming system, involving micro organisms, soil flora and fauna, plants and animals.
To maintain and increase long-term fertility and conservation of soils.
To promote the healthy use, conservation and proper care of water, water resources and all the life it holds.
To use, as far as possible, renewable resources in our agricultural systems, and to use them at a rate less than their replacement.
To work, as far as possible, within a closed system with regard to organic matter and nutrient elements, maximizing our use and minimizing the waste of what we produce.
To work, as far as possible, with materials and substances that can be reused or recycled, either on the farm or elsewhere.
To give all livestock conditions of life which allow them to perform basic aspects of their innate behavior.
To minimize all forms of pollution and other negative impact on global ecological systems that may result from agricultural practice.
To maintain the genetic diversity of the agricultural system and its surroundings, including the protection of plant and wildlife habitats.
To allow everyone involved in organic production an adequate return and satisfaction from their work, including a safe working environment.
To work to avoid exploiting people and other cultures.
To consider the wider social and ecological impact of our farming systems beyond Twin Oaks.
To expand knowledge and access to information about sustainable agriculture.
To progress towards an entire organic production chain, which is both socially just and ecologically responsible.
The Purpose of the Twin Oaks Sustainable Agriculture Pledge is
to be more intentional about our agriculture,
to be more transparent (so that anyone can easily know what our agriculture managers might be doing), and more accountable to the membership,
to improve our communication about our agricultural practices
to improve co-operation between agricultural areas
to align practices in our agricultural areas as far as possible
Our Reasons for Doing This
The various agricultural areas at TO, including our agricultural income areas and food processing areas, operate independently on a day-to-day basis, although we are all part of TO Community and our collective budgeting system .
We all work within the TO precepts listed in our Bylaws, including “C. …assum(ing) responsibility for maintaining the availability of natural resources for present and future generations through ecologically sound production and consumption;” and “G. …striv(ing) to be self-reliant by producing for itself the goods and services necessary for the maintenance of the Community.”
Our Statement of Religious Beliefs proclaims, among other things, that we endeavor “To respect and preserve the natural environment for the use of our own and other species, now and in the future.”
Members have an expectation that our farming is loosely organic but we leave it to managers to decide on practices within their area. There is an increased desire in the community for more sustainability.
Although our agricultural practices are open to any member who wants to inquire, if we don’t ask, things can happen which most of us don’t support.
We hope to increase the discussion in the community about sustainability and agriculture, increase our awareness and intentionality, and move us towards greater sustainability.
Sustainable agriculture will require and support a sustainable society. Our challenge is to meet human needs without denying our descendents’ birthright to the natural inheritance of this planet.
The costs and fragility of the present system of American agriculture are becoming each day more evident.
Sustainable systems are more efficient in their use of energy, biological sources of fertility and pest management, and enhance rural communities and encourage people to remain on the land.
A sustainable agriculture that provides nourishing food, protects those who work the land, helps stabilize the earth’s climate, and safeguards soil and water depends on our ability to meet a number of challenges. Organizing to acknowledge and address these challenges together increases our chance of success.
Reasons for Writing our own Pledge Rather than Applying for USDA Organic Certification
USDA Organic symbol
Our Tofu and Seed Growing businesses are USDA certified, for good reasons, as they sell to the public, and people look for the USDA symbol. But we believe the domestic areas would not benefit from Organic Certification, which involves a lot of paperwork, and some restrictions which would cost us a lot of money. Additionally, USDA Organic Certification is focused solely on the contents of the product. There are many other aspects of our farming that we care about –
locally produced food, minimal food miles,
freshness, flavor,
fair treatment of workers, worker safety and well-being,
carbon footprint, sustainability for the future of the planet,
humane treatment of livestock,
water, soil and wildlife protection,
food safety, nutritional content,
social and economic responsibility both locally and globally,
efficient use of fuel and other resources,
responsible stewardship of the land.
Our concerns are much wider and deeper than just the organic product. Also, we want a method that is in keeping with our trust-based system, not one of outside inspectors.
Sources of Inspiration, and Ideas we Have Drawn From
Certified Naturally Grown logo
Certified Naturally Grown which is an organization for farmers following the USDA standards without getting certified. https://www.naturallygrown.org/
OMRI (Organic Materials Research Institute) lists products acceptable for use by USDA certified farms. https://www.omri.org/
IFOAM (International Federation of Organic Agricultural Movements) https://www.ifoam.bio/and https://www.ifoam.bio/why-organic
We have based our Sustainability Pledge initially on the IFOAM (International Federation of Organic Agricultural Movements) principles and standards for organic agriculture.
Each Twin Oaks Managerial Area may define its own sustainable agriculture Practices, based on the shared principles in our Pledge.
I follow the news from Sandra and Lynn at Lynbreck Croft in the Cairngorms National Park of Scotland. They have been guardians of that 150 acres since 2016, restoring the degraded landscape. They grow vegetables, raise long-haired Highland cattle, native rare-breed pigs, honeybees and egg-laying hens. They butcher their own livestock, sell food super-locally, teach courses on the croft, and provide tours by arrangement. They have planted nearly 30,000 trees and installed fencing to keep the land in good heart.
Cover image of Our Wild Farming LIfe book.Chelsea Green Publishers
They are members of the UK Agricology Tree Fodder Hub, a group promoting using shrubs and trees as supplementary livestock feed. This was once an important component of animal husbandry, either browsed fresh or harvested and fed dried (“tree hay”) in winter. There is an increasing interest in this practice as it is sustainable, perennial, no-till, and answers a need for those farming in regions with short summers wanting a low-input system that maintains animal health and welfare.
Trees in the animals’ landscape provide not just browse but also shade and shelter. The animals are able to select the varieties and species best suited to their nutritional and medicinal needs and personal preferences.
The Hub includes research into usefulness of various trees, their role in moderating climate change impacts; building soil health; sustaining insect, amphibian, reptile, fungal and bird life; and a link to TreeFEED: Trees for Forage: Short term plantings to enhance livestock production, health and resilience. (Trials of the TreeFEED project carried out in Cornwall by Farm Carbon Toolkit.)Cattle browsing for feed.
Agricology’s Tree Fodder Technical Guideincorporates in its 36 pages a wide range of research and farmer stories, videos, blogs, offering opportunities to learn from other farmers, explore different approaches and pick up practical suggestions.
“Findings & recommendations
Tree fodder provides supplementary nutrition, minerals, and medicinal compounds, supporting livestock health and resilience, especially during dry seasons or winter months.
Domesticated animals naturally browse on trees and shrubs, with goats and sheep showing higher intake due to their ability to digest anti-nutritional factors.
Tree fodder is comparable to grasses and forbs in macronutrients and can be superior in protein, fat, and sugar content.
Tree fodder is a stable source of minerals like zinc, cobalt, selenium, and calcium, which vary by species, location, and season.
Condensed tannins and salicylic compounds in tree fodder can provide health benefits, such as reducing methane emissions, managing intestinal parasites, and treating inflammation and pain.
Direct browsing, cut-and-drop feeding, tree hay, and silage are effective ways to provide tree fodder. Tree hay is highly palatable and can be stored for winter use.
Pollarding and shredding are effective methods for harvesting tree fodder. Proper timing and storage are crucial for preserving nutritional value.
Case studies: Farmers Tim Downes and Lynn Cassells and Sandra Baer [of Lynbreck Croft] have successfully integrated tree fodder into their systems, improving livestock health, fertility, and resilience while reducing reliance on chemical treatments.
Recommendations: Incorporate diverse tree species for nutrition, shade, and shelter; manage trees for optimal growth and accessibility; and explore tree fodder as a sustainable supplement to traditional feed.”
The front cover of Permaculture Gardening for Everyone , by Nicky Schauder
Book Review: Permaculture Gardening for Everyone: How to Use Permaculture to grow Abundantly at Home. Nicky Schauder. Ogden Publications. August 2025. 128 pages, $17.99
This is a beginner vegetable gardening book for those interested in trying some permaculture approaches. It’s a slim, attractive, well-illustrated book, written in a very accessible conversational style, and includes workbook pages. Nicky and her husband Dave have six children, and the first two were diagnosed with severe food allergies to tree nuts, peanuts and fish. They were spurred by this difficulty to grow food for their children that was free of chemicals that could be driving the big increase in food allergies in the US. They chose permaculture because it includes the whole environment around the food.
Permaculture practitioners have contributed to a greener planet, more sustainable living and food abundance. Although Permaculture promotes perennial crops, it recognizes that the bulk of our food crops are annual plants. By focusing on circular, regenerative systems, permaculture design aims to use the end products and byproducts of one process to create new processes that generate new growth and feed the soil. The ethics of permaculture are earth care, people care and fair share.
Permaculture’s cocreator David Holmgren listed 12 principles to constantly practice:
Observe and interact
Catch and store energy
Obtain a yield
Apply self-regulation and accept feedback
Use and value renewable resources and service
Produce no waste
Design from patterns to details
Integrate rather than segregate
Use small and slow solutions
Use and value diversity
Use edges and value the marginal
Creatively use and respond to change
Probably some of these speak to you clearer than others, but all are worth considering.
Permaculture Gardening for Everyone Chapter 2
Nicky starts with a chapter about growing sprouts and microgreens, vegetables you can grow before you set up a garden. Not an obvious place to start permaculture, but a very accessible one. There are clear instructions and a chart of seven popular sprouts, including their germination temperatures, how much seed you need for a 1020 sprouting tray and how long the harvested sprouts will keep in the fridge.
The next chapter is about garden design, and Nicky encourages a practice of 10 minutes of garden observation and journal recording daily for ten days, followed by seven minutes a day “for the rest of your life”. Observe patterns of climate, topography, water, wind, existing vegetation, weeds, wildlife, access and aesthetics. On Day 1, simply observe, reflect and record your observations. On Day 2, notice patterns – patterns happen when two or media converge: water with wind; seeds, petals, sepals in a sunflower head; water running over land. There are practical ways such patterns can be applied. Permaculture has a language of plant guilds and zones. The ideas can be applied even if you don’t adopt that language. The point is to notice and use patterns.
On Day 3, think about zones of use for efficient and sustainable land management. Have things that need daily attention nearest to your house. Work outwards to frequently-used areas, semi-intensive cultivation, occasional visits, minimal care and finally, unmanaged wilderness (a small town garden won’t have much of that). Day 4 is for climate and micro-climate observation. Use forecasts and observations of temperature, precipitation, wind speed and direction at various times of the day. On Day 5 find your microclimates – hot, cool, dry, wet, sheltered.
Day 6 is for observing topography, the curves and contours of your land. Compare your land with a map, and think about where you will put raised beds, a pond or wetland, swales to hold water. Observe locations of power lines and utilities. Day 7 is devoted to water and its management: how can you channel the water where you’d like it to go? If it rains on Day 7 you are lucky: you can directly observe the flows.
Day 8 is for observing where people walk, so you can plan paths and sitting areas, growing areas and storage areas, ensuring everywhere is accessible in the ways you need it to be. Where possible, double up on functions of a space, using tool storage boxes as benches to sit on.
On Day 9 observe the existing vegetation and learn what it is telling you about the previous use of that space, its dampness, soil acidity or compaction. And on Day 10, thoughtfully plan your yard.
Chapter 4 is about choosing your plants. Because plant diversity is important in creating symbiotic relationships and long-term stability in the soil micro-organisms, it is wise to choose vegetables from as many of the 7 common plant families as you can. That’s brassicas (cabbage etc), solanaceae (nightshades), cucurbits (cucumbers, melons, squash), legumes (peas and beans), amaranths (spinach, chard, beets), umbelliferae (carrots, parsley, celery) and alliums (onions, garlic). Nicky recommends also adding something from the mint family and the aster family (lettuce, sunflowers). Also consider perennials. Fit with your climate and the type of soil you have. You could follow John Jeavons and rotate crops between heavy givers (legumes), heavy feeders (tomatoes, squash, brassicas) and light feeders (root crops, spinach, lettuce).
There is a kitchen garden plan to critique, particularly answering whether it needs more diversity. It has a row of 22 yarrow plants, which left me mystified (they’re to deter deer, I found out later). Hardly any actual vegetables (just bunching onions). Strawberries, mint, sage and oregano for culinary use. Seven patches of anise hyssop, a mostly medicinal herb. Eight sunflowers. Lots of apparently empty space. Is it lawn? Bare soil? There are no brassicas, nightshades, cucurbits, legumes or amaranths. Is this a trick quiz, or a worksheet for us to fill out?
There’s a stepwise system for planning which crops to include, looking at what time of year they have the best conditions, then creating a crop template for each of the four quarters of the year, in just one bed at a time. Lay out all your annual garden beds in a diverse and complementary manner, deciding what you want to grow and eat in each quarter. The next step for each bed is to look at which crops might follow after the first season. And if possible, integrate perennials. There are worksheets to help you.
Chapter 5 is on starting seeds. Nicky favors using only 1020 flats and dividing them with twine or tape into 4 sections. This idea works best when the crops sharing a flat like similar germination temperatures and take a similar number of days to emerge. Calculate how many plants you’ll need of each crop, add a buffer and sow that number of seeds. Number of plants needed = average annual amount consumed per person divided by the yield per plant. As soon as one flat is emptied, you can refill it and sow the next “wave” of four crops.
Chapter 6 is on preparing your soil (while your flats of seedlings are germinating!). Nicky recommends taking lots of “before” photos, then inviting a large group of friends and neighbors to “install” your garden, that is, make up the beds and paths. Ahead of that day, prepare a detailed plan of the steps you’ll need to take. The book contains advice on this! Nicky uses a “scrum” board, a wall with rows and columns of sticky notes. The column headings are Backlog/To Do/Doing/Done. Each major project has a column of sticky notes, one for each task within the project, along with how many hours of work it might take, and the tasks must be done in order. Each sticky note gets moved from left to right according to progress.
I got distracted by the description of mortaring bricks into walls. Nicky’s mortar must be rather different from UK mortar. With this kind, you line up the bricks, mix the mortar, let it set overnight, then mortar the bricks, let them set, then put them in place. Be sure you have the right kind of mortar for this method!
Prepare your soil to be in the best possible chemical, physical and biological shape, before you plant anything (especially perennials). Get soil tests, interpret the results and decide on amendments. Set your plants up to achieve maximum photosynthesis, maximum protein synthesis, good lipid synthesis and phytonutrient synthesis, in line with John Kempf’s Plant Health Pyramid.
Author Nicky Schauder
As well as the chemical composition of the soil, the biology and the physiology of the soil are vitally important. Read up about soil fungi and bacteria (and archaea) and the balance between them. Different plants thrive according to whether the soil is fungal or bacterial dominant, and the pH will be different. Six important soil rules are to limit disturbance, keep the soil covered (with plants), promote diversity of plant and animal species, grow cover crops, integrate animals where appropriate, and work within your climate and geography, and your spiritual, social and economic context. Nicky and husband Dave have a set of four videos for Mother Earth News members: https://www.motherearthnews.com/courses/seasonal-garden-planning/. In the book, there’s a garden installation checklist to help you plan for a group “barn-raising” type of intense garden creation.
Chapter 7 is about transplanting seedlings, carefully explained for beginners, including how to decided if your transplants are ready to go out (Big enough? Needs potting up for a longer stay inside? Do they have two true leaves yet? Do they have enough roots? Are they sufficiently hardened off? Is the outdoor soil warm enough? Have you got the tools you need?)
To help with planning the fall growing season, there’s information on frost tolerance and days to harvest for nine hardy leafy greens, and information on cloches, low tunnels, cold frames, hoop houses and greenhouses.
Chapter 8 covers maintaining your garden: plant supports, mulching, watering, wind protection, pests and diseases. Nicky’s main recommendations for dealing with insect pests are diverse plantings to help the pests get lost; umbellifer plants to attract predatory insects; diatomaceous earth against crawling insects; Beauvaria bassiana (a naturally occurring fungus) as a last resort; borax or neem oil against ants.
Pest mammals are harder to deal with. Nicky suggests fencing, and planting aromatic herbs such as thyme, basil, anise hyssop and yarrow to dissuade deer. You do have to plant a lot for this strategy to work. Good fences, especially double-layer angled fences are the best solution, although motion-sensor lights and water sprays can work.
Weeds are worth studying, to better understand their successful strategies. Identify your weeds, deal with them while they are small, try flaming or solarizing, pull by hand, mulch heavily, and start with crops that are the most competitive with weeds.
Plant diseases are legion, and identification is essential to effective treatment. Nicky is a fan of aerated compost teas, or hydrogen peroxide.
The last chapter is about harvesting, choosing the right time (don’t harvest too soon, or you get less, and it might not taste as good). Sweet potatoes continue to bulk up as long as temperatures remain over 75F. Wait for your cabbages to form firm heads and get your broccoli before the buds open; learn how to recognize ripe melons. Consider recording your harvests as a way of assessing how well you are doing.
Lastly, prepare for your next crop. Start transplants 1-2 months before the expected end of the previous crop. Prioritize establishing the new crop over getting every last morsel from the old crop. Make a planning calendar, tweaking it each year in light of what you observed the previous year.
This book will be valuable to complete beginners, to guide them into producing food, and to doing so effectively and regeneratively. It will help build confidence where that was scarce.
Five Star Grape tomato in our hoophouse. Photo Alexis Yamashita
Soil Test Results: Hoophouse Soil pH
Last week I promised to say more about soil tests, pH and what we are doing to improve our hoophouse soil.
The pH is a measure of how acidic or alkaline (basic) a solution is, assessed on a scale from 0 to 14. It is based on the concentration of hydrogen ions. Think of the “p” as standing for Potential, and the “H” as standing for Hydrogen ions. The lower the number, the higher the concentration of H ions (less Potential left!) and the more acidic. Pure water is neutral (neither acidic nor alkaline), at the midpoint of the pH scale, with pH rated as 7.0. Substances with a pH less than 7 are acidic; those with a pH greater than 7 are alkaline.
Battery acid has a pH of 0; lemons measure about 2, and milk measures between 6 and 7. To dig deeper it is important to understand that the pH scale is a logarithmic scale, meaning that each whole number change in pH represents a tenfold increase or decrease in acidity or alkalinity. A solution with a pH of 4 is ten times more acidic than one with a pH of 5. A pH of 3 is 100 times more acidic than a pH of 5 (10 x 10).
Image from epa.gov
A good place to start learning more about soil testing is
There you can find an explanation about the value of soil testing and info on choosing a soil testing lab. The one nutrient that is often not assessed is nitrogen, which combines readily within the soil with other materials, making it difficult to measure and interpret results. See Soil Microbial Nitrogen Cycling for Organic Farms for more information.
Lime recommendations made by soil testing labs use two different soil tests: soil pH and buffer pH. Buffer pH measures the soil’s resistance to changes in pH, which affects how much lime is required to increase soil pH to a target pH (or sulfur to lower it). Soils high in OM and clay need more lime to raise pH than sandy, low OM soils do. For example, a sandy soil with pH 5.0 may need 1 ton of ground limestone to raise the pH to 6.5, while a clay soil with the same pH may need 4 tons. Each soil testing lab has its own buffer solution and tables or formulas used for calculating amendment requirements.
Our hoophouse beds after the nights at 2F (-17C) and 8F (-13C). Looking amazing! Pam Dawling
Virginia Tech recommends writing in a crop code number on the form you send in with your sample, even if you will be growing a mix of vegetables next year. This enables them to give a recommendation, which you can modify as needed. You could choose the crop which will occupy the most space in the area, or a representative of the main crop family. For example, for brassicas, choose Cabbage. Their document linked in the title gives the numerical equivalents of the L- to VH ratings for P, K, Ca, Mg results, and soil test calibrations related to soil pH for Zn and Mn. There is also a list of Critical Soil Test Levels for various factors, giving you a heads-up when action is needed to remedy a problem. Also included are fertilizer recommendations for NPK. You will need to get the equivalent information from your local extension office or the organization that did your soil tests, as testing procedures vary.
Dealing with Alkaline Hoophouse Soil
Outdoors, we more often need to make the soil less acidic, so we add lime. Adding sulfur to the soil can make soil more acidic (bring down the pH). This is commonly done before growing blueberries for example.
Blueberry bush with buds in March. Photo Pam Dawling
The Clemson Soil Acidification Calculator lets you enter your data and learn how much sulfur to add. (And if you need a lime calculator instead, to reduce the acidity of your soil, they have a calculator for that too.) Sulfur additions can take many months to show results. For example, to reduce the pH of loamy soil from 7.2 to 6.5, the calculator informs me I would need to add 12.6lbs/1000ft2 of elemental sulfur, and that this is too much to add all at once, so would be best divided into at least two applications with a gap of 2-3 months between applications. They further recommend re-checking the pH before subsequent applications. They recommend only applying S when temperatures are cool (<75°F), and to water in immediately after application.
Elemental Sulfur from Seven Springs Farm Supply, Floyd, VA
Water-soluble products can be a way to bring down the soil pH in hoophouses.
Hoophouse soils can drift towards alkaline over time (partly due to the pH of the irrigation water) and need a little acidification. The pelleted elemental sulfur used outdoors is unsuitable for use in covered spaces that have drip irrigation, as the pellets will not readily break apart.
Magnesium Sulfate (Epsom salts) from Seven Springs Farm Supply, Floyd, VA
Aluminum sulfate (28.1% S) could be used in the above example at 84lbs/1000ft2 dissolved in water. But it can damage plants and is not OMRI listed. Instead, use OMRI listed Epsom salts (magnesium sulfate), which is 12.9% S. Consider that this practice may actually lead to more problems, as the acids used to bring the pH down can add additional salts to the soil, in this case aluminum or magnesium.
See the U of Minnesota Soil health and nutrient management in high tunnels. Hoophouse soils have particular nutrient management needs. The yield potential of hoophouse crops is usually 2-4 times more than outdoors. At higher yield potential, the need for nutrients naturally also increases. Adding organic matter (OM) to your soil as compost can improve its aggregate stability, and nutrient and water retention. Clay soils and those with high OM allow moisture to spread out from the drip emitters and the roots can extend farther. For this reason, all hoophouses need generous amounts of compost added to the soil at planting time. This is particularly important in sandy soils due to low water-holding capacity.
One of many wheelbarrows full of compost we spread every year. Photo Wren Vile
However, too much compost can cause problems with water retention, especially if compost is left on the surface rather than incorporated, and can lead to high levels of phosphorus accumulation. Incorporate compost and manure into the soil rather than leaving it on the surface. This helps prevent compost from drying out on the soil surface and resisting water absorption. Some soil testing labs report finding granular fertilizers included in hoophouse soil samples submitted to them! Granular products do not get absorbed into hoophouse soil where drip irrigation is used.
Many growers start with a balanced fertilizer (a product containing equal amounts of nitrogen, phosphorus, and potassium). They are often used alongside fertilizers providing only nitrogen, as relying only on balanced fertilizers will result in phosphorus build-up. Use plant-based composts rather than animal-based ones in hoophouses unless your soil is deficient in phosphorus. Even if no animal composts are used, phosphorus can build up.
Nitrogen Fertilizers for Organic Hoophouses
Here are three options for supplying adequate concentrated nitrogen to organic hoophouse crops. All provide readily available nitrogen, but can lead to salt build-up if applied in excess or if not mixed thoroughly into the soil.
Feather meal (13-0-0): This insoluble product does not work for fertigation or foliar applications.
Bloodmeal (12-0-0) and Fish emulsion (5-1-1): can be applied as a foliar spray, but may clog drip lines if applied via fertigation. Fish meal has a ratio of about 10-6-0. Some forms are water soluble, others not.
Legume Cover Crops for Hoophouses
Crimson clover cover crop with bumblebees. Photo Bridget Aleshire
In addition to adding fertilizers, consider using cover crops and reducing tillage. Legume cover crops can supply nitrogen without increasing phosphorus levels. Legumes fix nitrogen from the air and gradually release it into the soil when the cover crop residues break down.
The University of Minnesota recommends the following legumes for their climate:
Fall planting: Austrian winter peas, hairy vetch
Winter planting (before your spring/summer crop): field peas, crimson clover
Summer planting: southern peas, crimson clover
Potassium Sources for Organic Hoophouses
Once fruiting starts, the need for potassium increases dramatically. Potassium sulfate or potassium magnesium sulfate are common in organic systems, and you can apply most of the potassium at planting and then side-dress the rest midway through the season. Potassium nitrate and potassium chloride are water-soluble and work well with fertigation systems, but are usually not allowed in organic systems.
Calcium and Magnesium Sources for Organic Hoophouses
If the soil pH is maintained in the optimum range of 6-7, calcium and magnesium are usually in sufficient amounts. Dolomitic lime supplies both Ca and Mg. If the soil pH is above 6, lime is not required, and gypsum (Ca-sulfate) and Ca-nitrate can be used to supply Ca.
Epsom salts (Mg-sulfate) and potassium magnesium sulfate will supply Mg without changing pH. Various sulfate compounds, such as gypsum, Epsom salts, potassium sulfate, and potassium magnesium sulfate, are sources of the secondary nutrient sulfur, and may be the amendment of choice if your soil needs acidification.
