Winter has finally come and it's time to start thinking about our gardens for spring. In this blog post we will talk about the soil
The best piece of advice I was given was to start gardening as soon as you can, while you can afford to make mistakes. It takes years of gardening to understand how best to grow your crops, deal with different weather conditions and pest situations. I have been gardening/farming for 31 years and I am still learning. I still can't grow a decent onion!
An important lesson I learned, sad to say only a few years ago, was how to enrich my soil organically. No fertilizers needed, no tilling and lots of composting. I want to share some of that with you as it is one of the key factors in healthy, productive crops and a money saver.
I was taught that the soil needed to be dug up, turned over and tilled every spring before planting. Then to go pick up compost from the city compost site to spread on the garden before planting my seeds and apply fertilizer throughout the season. Turns out, this is not the most productive plan. I was also taught to replace perennials every 5 years, or at least move them to a new location. Also not true. These common teachings are costly and decrease productivity.
To restore soil health, there are four main principles: (1) Less soil disturbance, (2). More plant diversity, (3) Living roots as much as possible and (4) Keep the soil covered at all times. (See A Soil Owners Manual. by Jon Sitka). So let's talk about that.
We want less soil disturbance or no till. Why? "Tilling the soil.... is destructive... Tilling destroys the soil's structural stability made up of soil aggregates (the little crumbs, clumps and blocks that give soil the capacity to act as a living, porous medium to store and supply a filtered water source). Eighty percent of the organic matter in the soil is held within soil aggregates less than 2 mm in size." Soil aggregates are built by soil microorganisms and plants, not by tillage. Tillage causes loss of the organic glues that keep soil aggregates water soluble. The soil organisms that drive soil health feed on Carbon, which is provided by plant material. This is why it is important to have living plants occupy the soil as much of the time as possible (cover cropping over winter). Nutrients cycle from the plants to soil organisms and back to the plants.
By tilling the soil, oxygen is added and soil aggregates are fractured. This makes the organic material in your soil more available to the soil bacteria to consume quickly and be less available for your plants to use.
As soil organic matter increases, so does its water holding capacity (so less need for you to water) and nutrient content of soil for the plants. The easiest source of food for soil microbes is the sugar provided by the roots of living plants. Next food source is the dead plant roots, flowers and leaves and then by above ground crop residues, such as straw, chuff, husks, stalks, flowers and leaves. So what are these soil microbes? They are bacteria, mycorrhizal fungi, protozoa, nematodes and earthworms. All of these organisms are fragile and dependent on proper air pores in the soil and water films (held in soil aggregates) to function and move around the soil. Can you more clearly understand why we do not want to disturb the soil? You lose water holding capacity, the soil food web and soil structure for it all to function in.
For least disturbance when planting, use a small tool to open up a hold large enough to put your plant in without disturbing the rest of the soil bed. If planting seeds, just punch a finger hole for seed to go in and move to the next spot.
Plant Diversity is important for soil health as each plant requires certain percentages of nutrients and provides nutrients to the soil. You don't want all one crop pulling out all of one particular nutrient from the soil and depleting it. This is the main reason behind the concept of crop rotation, but we can and should take it further by not planting a large area of a single crop, but intersperse the crops within the same garden bed. This could look like 2 rows of crop one followed by 2 rows of crop 2 and then maybe a third crop or back to first crop. Personally, I don't use rows, but blocks with the same idea. This prevents a single crop demanding all the nitrogen in a given space, or can mix with a crop that is a nitrogen fixer and puts nitrogen into the soil. There has been a log of research done on this concept in the Dakota's and they recommend a 6 crop diversity in a farm field.
Living Plants and their roots are the most practical way to restore soil health. They feed the fungi and soil microbes with the sugars of their roots, create air pores, prevent soil erosion and help contain the organic matter in the soil. So forget the old plant in rows spaced 1 or 2 feet with lots of open space idea.
Soil Cover is important to protect the fragile soil aggregate structure. This could be placing leaves, grass clippings, straw, mulch, cover crop onto soil bed. This soil cover also helps conserve moisture, prevent damage to aggregates from raindrops, suppress weed growth and provide a habitat for the soil food web organisms.
When considering what soil cover to use, consider its ability to provide nutrients to the soil as it decomposes and what its Carbon:Nitrogen ratio is. The higher the C:N ratio, the slower it will decompose . I recommend reading A Soil Owners Manual by Jon Sitka for more information on this. Basically, wood mulch decomposes very slowly and has a high N:C ratio. It can be used but provides little nutrients to your crop that is growing. Be thoughtful as to where you source your mulch so not putting down diseased, infested or sprayed material onto your garden. Utilizing leaves and grass clipping, hay or straw can be quite cost effective. I try to rotate what I use for a cover, but find wood mulch the most visually pleasing to work with in the front gardens.
Are you starting a new garden bed or need to refurbish an old soil bed? The best indicator of a productive crop there is the amount of time and effort you put into preparing the soil. If you are putting a bed in where grass exists, I like to just cut off the top of the grass layer and add a mixture of compost, vermiculite, and top soil on top of the area. Others like to dig up the grass and roots and place their new soil mix on top. If you are preparing a raised garden bed, consider adding sticks and leaves to the bottom half of the bed and then adding your soil mix to the top. This allows for a long decomposition to feed the soil from below and saves on the cost of the soil and compost. Some people choose to till their new garden bed, add a quality soil mix and then never till again. It just won't be as productive the first year as the soil structure develops.
So what makes a good soil mixture?
Top Soil. make sure you are getting quality, organic soil. you don't want someone's herbicide or pesticides in your fresh new soil.
Compost. This can be a mix of kitchen waste, branches, grass clippings, garden waste, leaves and manure. It is very important to use an organic compost, whether you make it yourself or buy it. In our cities compost sites, it is free to anyone but keep in mind, you do not know what yard waste went in there. Diseased and sprayed plants or grass often goes in there. I am excited to share with you a new source of high nutrient and organic compost available. Noreen Thomas at Doubting Thomas farms, finished her fellowship in developing an organic compost and it is being offered starting this spring at Nygaard's Greenhouse in Dilworth. This is beautiful stuff. I used it last year in 2 of my beds I was refurbishing and I had double the harvest of my herbs in those beds than the same herbs grown in other beds.
If you want to make your own compost, you can build a structure to contain the pile as you build it up, allowing you to stir it and water it. If doing a traditional compost pile,
remember the rule of 2 parts green (plant material, kitchen scraps, eggs) to 1 part brown (leaves, twigs, wood chips). Periodically add some garden soil or fermented herbal fertilizer to introduce microbes. (recipes to make fermented herbal fertilizer can be found in our new subscription pages).
Another method is to dig a hole about 2 feet deep and fill it with kitchen scraps and leaves and cover it. Keep making holes as you collect enough kitchen scraps to put into a compost hole. These will decompose and you have nutrients feeding into your soil all winter and summer. Just bury deep enough that critters can't smell it and dig it up.
Leaf Mold. This is a beautiful humus product that is so easy to do in your yard. I picked a spot in my yard next to my water barrels and set up a circular chicken wire fence and filled it with leaves in the fall. Other than watering the leaf mold pile when I water my garden, there is nothing else to it. Let it sit and work on decomposing itself. The following fall (so 1 year sit time), I pull off the chicken wire cage and shovel the lovely decomposed leaves, which looks like an airy, black soil, onto my gardens to be prepared for spring planting. It's free, clean and nourishing for your garden and you don't have to bag the nutritious leaves and waste them.
Other Soil Ammendments
To know for sure what soil amendments your garden needs, work with your local county extension agent to do a soil test. Then add from a choice of these amendments to make your soil more productive.
Pine bark fines - ground up pine tree bark, which is easiest to find near logging sites
Worm castings and fish meal
Nitrogen - legume cover crops (red clover, alfalfa, vetch, fenugreek, field peas), blood meal, feather meal, fish meal, poultry manure, liquid fish emulsion
Phosphorus - organic matter, rock phosphate and bone meal
Potassium - composted animal manures (test for e.coli), kelp meal, wood ash, liquid fish emulsion
Trace Minerals - kelp powder, liquid kelp, azomite (mined volcanic mineral)
Soil pH - add lime to acidic soils and organic matter to alkaline soils
So, start working on your plans for a healthy garden soil this winter. What size do you need? What are you planting and where? have fun with it.
Some resources:
A Soil Owners Manual by Jon Stika
The Healthy Garden by Juliet Blankespoor
The Organic Medicinal Herb Farmer. by Jeff and Melanie Carpenter