I hope all of you are still enjoying some nice fall/winter veggies from your garden! This is the time of year when all that fall planting pays off and you get to harvest delicious kales, brussels sprouts, cabbages, endive, and more frost-sweetened veggies for the holidays. And they all taste so much better than anything from the store! There are many important tasks in the garden this time of year, and many involve protecting your soil and plants from weather extremes. This can take the form of protecting tender plants with crop cover fabric, cold frames, tarps, and even greenhouses. Protecting areas from becoming waterlogged and extending your harvest season and range of plants you can grow year-round is just one of the benefits. But I’d like to focus on what I consider to be the most critical component of winter gardening in our area: Mulching and how to create and restore soil health for the long term!
The Bigger Picture, Up Close
For most of us living in the Puget Sound region, we live in what is known as the “Puget Lowlands” ecoregion https://www.oneearth.org/ecoregions/puget-lowland-forests/ or the “Pacific Northwest Coastal Forest” ecoregion https://www.oneearth.org/ecoregions/central-pacific-northwest-coastal-forests/ . In general, we have fragile soils that aren’t extremely deep and are easily eroded during the winters when not covered by vegetation due to our high rainfall. Much of the original protective layer of vegetation (forest duff in most cases) has been removed through development in urban areas and the clearing of farmland. Much of our farmland has been converted into heavily grazed and heavily eroded pasture. There is a lot we can do to reverse this erosion, and some of that work happens in the winter simply by letting your land “rest” and re-absorb some of the organic matter sitting on the surface of the soil, and in some cases adding organic matter where there is none. Regenerating soil takes time, and it always starts with careful observation of the land you live on.
I encourage you to get a nice mug of tea or coffee, bundle up, and walk everywhere on your land and in your garden. Do this at different times of day, over the course of the winter. And carefully observe. It’s fun to involve kids in this exercise too. Together you can discover a lot. Where does the frost melt last in your garden each day? Where does the water linger longest after a hard rain? Where does the soil dry out first? What birds and insects do you see? Which areas are easy to grow plants or trees on, and where do your plants struggle the most? What’s happening in those areas in the winter? Where’s the bare soil on your property during the winter?
Garden Health Myths of the Past
In the past the widespread view was that everyone should focus on “tidying up” their garden as fall and winter set in, removing all the fallen leaves for curbside pickup, trimming back spent flower stalks to the ground, and removing all vegetative debris for yard waste pickup. This view was popularized in part due to a lack of information on local soil nutrient cycles and the soil food web, and the critical importance of organic matter to our native populations of insects, birds, invertebrates, amphibians, fungi and soil microbes in maintaining the balance and health of our farm and garden environments. Did you know that most pollination on farms and in gardens is done by native pollinators, not the non-native honey bees we hear so much about? Most of us were raised to dislike “messy” yard debris, and the microbes (aka “germs and bacteria”), fungi and numerous other critters that live in it. Now we know the importance of all these critters in maintaining the health and productivity of our plants and gardens and farms. Because we eat food produced from the soil in our gardens and farms, it’s important to make the connection that a healthy human gut micro-biome is intricately linked with the health and biological activity of the soil that produces the plants we eat, and that our livestock eat. Bio-Regionally specific information regarding the interaction of climate, soil life, nutrient cycles, insect and higher life form populations and how these things interact is critical to long-term sustainability, and has gotten a lot more study over the last decade. Part of this is due to the emergence of irrefutable evidence of climate change, environmental degradation, and the loss of habitat and populations of native species. As our food system and food supply feels the stress, so do we. The rising cost of food is in part due to the increasingly frequent extreme climate events that are making it much more difficult for farmers to grow their crops the same way they have for the last 50 years.
The Case for a Less Tidy Garden
Organic matter, the leaves that fall from our trees, for example, and debris that accumulate from plants in general provide extremely valuable minerals and nutrients to our soil and the important microorganisms that live there, and by extension, to our trees and plants and the animals that consume them, us included. The microorganisms that live in soil have a symbiotic relationship with the plants that grow there and are responsible for feeding our plants a majority of the nutrients they receive. One of the most important ways to encourage healthy microorganism populations in our soils is to increase the amount of organic material in our soils. The insects that we want in our gardens, like ladybugs and native pollinators, rely on vegetative debris, hollow stems, and undisturbed soil in order to nest over winter and lay their next generation. The birds and beneficial insects that help control massive outbreaks of pathogenic insects that harm our gardens also depend on the seed-heads of spent flowers and the lingering fruits of various plants to help sustain them throughout the season. Here I’m talking about our native berries and shrubs, as well as non-native fruits in areas with few native plants, as is often the case in urban areas. Both are important.
I’m not advocating for keeping paths covered in leaves or diseased apples at the base of your apple tree. What I am encouraging is if you have to move that material, compost it in your own compost pile to add back to your beds later. But most importantly keep your garden beds covered as much as possible in organic material of your choice. Rake your leaves into your garden beds to break down and feed the soil over the winter, use straw mulch, plant cover crops in the fall, even cardboard in a pinch, but please don’t leave your soil bare in winter. In our garden I leave most of my plants intact in the fall and winter in the beds, only cutting off seed heads of invasives or plants I don’t want to spread. Most of the seeds will be eaten by birds over the winter. In the meantime the plant roots hold onto the soil, and the stalks, branches and leaves that break down help protect the surface of the soil from rain and hard frosts. For those beds that don’t have enough organic matter, I use straw as a mulch, which is cheap and covers a large area easily. In the spring when my plants start to emerge, if there’s an area of mulch that’s too thick or causing an issue, I just add the mulch to my compost pile to reincorporate into the soil later. I try to make sure every bed is covered in some kind of mulch or organic debris during the winter. Why is this so critical you may ask?
To start with, I will mention what many of you have no doubt already observed over the last decade: our climate in Puget sound is fluctuating to greater extremes on a regular basis. Whether it’s “atmospheric rivers” that dump even more water than usual during the winter, alternating with previously unknown longer periods of relatively dry weather in November, or prolonged 100+ degree weather in July or August, or 80 degree stretches in May with frost a week later, we’ve all noticed the extremes, and how much more frequently they occur. And so have our gardens and all the living things in there from soil microorganisms to bumble bees to Stellar Jays. Put simply, organic matter in our soils and the teeming life that it nurtures are crucial to helping our gardens, farms, and ecosystems adapt to and handle these extremes. Organic matter is critical to giving our soil and the life it supports the ability to bounce back.
Organic matter has the ability to absorb huge amounts of water during a rain event and then slowly release it into the soil. This is the opposite of massive amounts of water sheeting across our landscapes, eroding soil and carrying nutrients away while very little is actually deeply absorbed into the soil.
The other thing that organic matter does phenomenally well is help to break up heavy clay soil and assist in creating drainage and airways in the soil, which are critical for healthy populations of beneficial microbes. The very things that feed your plants nutrients. Organic matter feeds the microbes that feed your plants and keep them healthy. Just like the beneficial bacteria in your gut, plants depend on healthy populations of microbes in soil, who in turn depend on organic matter.
Our Strategies for Soil Restoration on a Larger Scale
2 ½ years ago when Eastside Urban expanded to our farm here in Oakville, approximately half of the 40 acres was degraded and compacted pasture with areas of both heavy clay and gravel. During major rain events, water would basically sheet off our pasture, carrying what little nutrients had accumulated near the surface, dumping into our neighbor’s adjoining field. The projects we are engaging in to regenerate our pasture area are fairly large scale compared to the intensive garden area around the house (~1.5 acres), but similarly focused on increasing organic matter in the soil to improve the soil health overall, while stopping the massive erosion that had been occurring every year for decades. The use of cover crops and plants like fracking radish to break up hard soil is just one of many strategies to improve and balance the soil here, and may work for you on your site, whether it’s a garden or a larger pasture.
A new cover crop I’m trying this year to improve a particularly difficult area of deep hardpan on our pasture is the sowing of fracking radish in that area. The long radishes can reach 18 or more inches and are left in the soil to break down and rot, creating channels of organic matter, oxygen, and a home for beneficial microbes and bacteria in the soil which was previously anaerobic and lacking in any organic matter. I’ll keep you posted on how it works out!
Instead of harvesting the hay produced every year in our pasture, we cut the hay more frequently and leave it in the field to break down, essentially composting on site and adding organic matter to the field. We have planted fruit and nut trees in the field in long rows approximately 30 ft apart, with the goal of creating long strips of regenerated soil (while also producing fruit and plants for the farm store). At first we could only amend each planting site with some compost, lime, and organic nutrients to give the trees a fighting chance. Every season we add more organic matter, hay, straw, compost, and nutrients as we acquire them. Now we have 10 rows of trees 4 feet wide, approximately 600 ft long, and 30 feet apart. These are oases of organic matter and nutrients slowly helping to regenerate populations of beneficial microbes and insects throughout that entire sector of the pasture.
In other areas of the pasture we’ve carved out some small swales and drainage channel areas to slow down and direct the water to specific areas during rain events. This allows the water to gradually sink in, instead of eroding the soil over most of the pasture during any heavy rain, as happened the first winter we were here. We’ve planted those same swale and channel areas (approximately 20 feet wide) heavily with native plants, trees, and shrubs. We never mow the areas by the swales or channels. This has helped restore native populations of pollinators, songbirds, raptors, amphibians, snakes, and salamanders. The massive overpopulation of field mice we had the first year has greatly decreased, and the insect problems we had the first year didn’t trouble us at all this last season. The difference in the health of our plants, both in the field and the thousands we produce (for the farm store) in our greenhouse (which sits near the field) over just 2 years is significant. We have never used pesticides or chemical fertilizers of any kind (both of which harm the microbial life of soil), and everything we do is focused on regenerating the health of the soil here.
With all that said about garden and pasture management, my goal is to encourage you this winter to start the process of regenerating your own soil and land by choosing to leave organic matter in your garden beds and on your soil as much as you can, wherever you can. I encourage you to leave as many of the seed heads on your flower-stalks for the birds and insects that you can. Try to find at least one area of your garden where you can pile sticks, branch cuttings, and similar debris for our native pollinators to nest. If you have bare soil, mulch it with straw or leaves this winter so that not only is it insulated from the cold and pounding rain all season, but the mulch you apply will add nutrients slowly over the entire course of the winter, and you will feed the entire soil food web. Your garden, land, plants, trees and all the living creatures there will thank you!
About me: After over 20 years in the sustainable landscaping and garden design industry both in the Pacific NW and in the UK, I opened Eastside Urban Farm & Garden Center in 2013 in Olympia, WA. My background combines Permaculture design, traditional horticulture training, organic gardening, and regenerative agriculture. My goal has always been to provide the tools, plants, products, and educational resources to help people grow their own food sustainably and organically, and to help them consciously design, maintain, and restore their land and farms in the most ecologically sound manner possible. I believe strongly that we are all tasked with leaving this world in a better state than we found it. My hope with this Blog is to provide folks in the South Sound clear information on general seasonal tasks, as well as specifics on various aspects of maintaining their farms, gardens, orchards, and homesteads. I believe that by working consciously to restore the land, ecosystems, and soil health, we can help create a healthier food system, a healthier Earth, and a better future for our children and generations to come.– Brighida deVargas