“If you were a tiny organism in a forest’s soil, you would be enmeshed in a carnival of activity, with mycelium constantly moving through subterranean landscapes like cellular waves, through dancing bacteria and swimming protozoa with nematodes like whales through a microcosmic sea of life.” – Paul Stamets in Mycelium Running: How Mushrooms Can Help Save the World.
In Part 2 of our soil-building series (Click here for Part 1), I will discuss five steps you can take to improve and fully restore the fertility of your garden soil. These steps come at a very low cost to you, and only require your full attention in the moment, and reflection as time goes on.
It is important to understand that healthy garden soil grows from a system of healthy practices, not just one practice. Adopt all or several of these practices and your garden will produce more food than it ever has!
Please note this post contains affiliate links which means if you click on a link and buy something I’ll get like 4 cents for it. All recommendations and advice are humbly my own, at no extra cost to you.
Related: How to Plan & Budget an Organic Vegetable Garden
1. Prepare Soil Using a No-Till Method
- One of the easiest, cheapest ways for us to improve the structure and increase the diverse microbial content of our soil is to ditch the machines. If you own a push rototiller, or a handheld cultivator like the Mantis, I have four words for you: Get. Rid. Of. It. Leave it on the curb, sell it on Craigslist, or better yet, smash it (suggested method here). Do whatever you have to do. Just please, for the love of mother earth, stop using this junk in your garden!
Preparing our soils in the spring should never be a mindless, mechanical process. Every garden is different, and you need to assess how much work will go into your soil prep based on the state of your soil. Every season will be different for your garden, and if you adopt intuitive, mindful soil prep practices now, the process will eventually require less of your input every year.
You will cultivate this intuition naturally, by spending time in your garden and making careful observations. I highly suggest keeping a notebook and photo journal of what you see. It takes time! But I will always say, the only way you can really get to know plants is by spending quality time with each and every one of them.
There is a common misconception that we must deeply aerate our garden beds every single spring. Allow me to blow your mind: We absolutely don’t! Your first year in your garden you will need to aerate the soil and amend it with compost and natural fertilizers. Existing gardens that are heavy clay, have a lot of rocks in them, or are very compacted, will also need one season or several seasons of aeration and amendment to build fertility and increase soil moisture holding capacity.
Fact of the matter is: You must be in tune with your garden to determine what it needs in the spring and throughout the growing season.
My preferred method of “intense” soil preparation is the Double Dig Method.
I first learned about double digging from John Jeavons, founder of Ecology Action and the Grow Biointensive farming method, and author of How to Grow More Vegetables, when he presented at the 2015 MOSES Organic Farming Conference. The Double Dig Method entails digging two layers of soil with a shovel using nothing but old-fashioned manual labor. Using the least amount of effort possible, the digger is to “twist” the soil in patches while amending it using organic fertilizers and compost. Watch this instructional YouTube video on double digging (note that there is a second part you’ll need to watch).
Here are some of my own double digging tips:
Tip 1: Double digging need only be done for in-ground gardens, or raised beds 6” and under. If you have a taller raised bed, simply hand cultivate it using a trowel. The method for hand cultivation is to “twist” the soil in the top 2-4 inches only – do not dig in and flip it over. Flipping the soil over will oxidize the microbial life.
Tip 2: When double digging your in-ground garden, use a fork like this one (my favorite for soil prep). Again, you want to twist and scoot the soil over more than you want to dig and flip it over on itself. The less disturbance the better! If there are weeds growing, pull them out and toss them back on top of the soil to be incorporated as organic matter (but remove them entirely if they’ve gone to seed!)
Tip 4: Double-digging might not need to be done every year. The idea is to build your soil fertility over the course of the growing season by also cover cropping and amending with good quality compost and natural fertilizers. Remember: Healthy soil results from a system of healthy practices.
The benefits of double digging are endless! There’s no intense breaking up of the soil structure. There’s no mass killing of valuable microorganisms, so plants are naturally healthier. All of your earthworms, spiders, centipedes and other beneficial bugs will be left in tact. Your plants’ root systems will grow deeper and stronger. And what’s fascinating is, once you build your soil fertility with organic matter your soil will hold more water, reducing the need to water as often.
Now the main point I want to make here is that no till is the absolute most important factor when prepping your soil. There are many other ways you could prep your garden other than the Double Dig Method – this is just my preferred way of prepping a brand new garden. Other options you could look into include sheet mulching and hügelkultur. Always remember there is no single, correct way to do anything when we garden – we work with nature, to restore her natural fertility, and let her take her course. It is so important for us to be open-minded and experimental when we garden!
2. Feed Your Soil with Compost and Compost Tea
Understanding what fertilizers are and why you are using them is the first step to feeding your garden properly. Most commercial fertilizers are made from synthetic materials that aren’t naturally-occurring at all – and the industry itself is incredibly dependent on fossil fuels. It’s just yucky business. So while using a slew of granulated synthetic fertilizers is an effective way to keep your plants dark green and happy for a short period, they can be irritating to earthworms and harmful to soil microbes, even if the fertilizer is organic.
What you really want to focus on, rather than feeding your plants, is feeding your microbes and introducing more of them into your garden throughout the season. The best fertilizer you could ever use is one you can make yourself, for free, in your own backyard… Compost!
Totally Related: How to Start a Biodiverse Compost Pile in 6 Steps
Compost is not the same as soil, nor is it mulch. Compost is a soil amendment and microbial inoculant. When made properly, compost contains the richest, most biodiverse concoction of microorganisms, and the richest mix of organic matter. By mixing compost into your garden soil and spraying your garden down with compost tea, you introduce a plethora of new, beneficial bacteria and fungi into your garden. Remember:
The more diverse your soil microbiology is, the healthier your plants will be.
Add compost to your garden at several times during the growing season:
- During Initial Soil Prep: If double digging, incorporate compost during this process. If you are not double digging, simply add a 3” layer of compost on top of your garden beds and sink a fork in every 6 inches to help incorporate the compost (this is a great tool for the job).
- Mid-Season: Side dress your long-term, heavy feeding plants with a few handfuls of compost a few months after planting. Sprinkle it around the base of your plants and gently scratch it into the soil surface with your fingers or soil knife.
- Compost Tea: Spray your homemade compost tea as much as you want! I highly recommend doing it on planting day and after that, once per month. You can absolutely spray more frequently if you are really into it (it’s totally okay to be really into compost tea!) Always apply when it is overcast or when the sun has gone down. Compost tea is ultimately the best microbial inoculant, and garden fertilizer, you could possibly use. For help on how to make it, I recommend this book: Teaming with Microbes: The Organic Gardener’s Guide to the Soil Food Web by Jeff Lowenfels and Wayne Lewis.
If you make your own compost, or have access to good quality compost, this will be the only “fertilizer” you need for your garden over time. There are a few other products I like to use during the season to feed my gardens, depending on their different needs… see the link below.
Totally Related: Best Soil Amendments and Natural Fertilizers for Your Organic Garden
3. Plant Polycultures and Practice Cover Cropping to Build Biodiversity
When I think about a polyculture, my mind dances up and down differing heights and textures of greenery, the soil is completely covered with plant material, and colorful blossoms poke themselves in and out of everything.
Polycultures, simply put, are communities of plants that are grown together to form beneficial relationships over time while increasing the biodiversity of the entire food web from soil microbes to birds. The plantings can be simple or incredibly in-depth, ranging from the beloved Three Sisters Guild of squash, corn and pole beans to edible forest gardens that contain a multitude of different species of plants (fruit trees, brambles, annual and perennial vegetables, etc) all growing together and benefitting one another.
Totally Related: 4 Steps to Cover Cropping Your Backyard Garden
Sounds like interplanting and companion planting, right? These two methods are indeed forms of polycultures, but both of them only scratch the surface. I say that not to dumb either of these methods down, but I think we can do better in terms of understanding plant relationships on a deeper level. When we truly understand how our plants work together and complement one another, that is when we become better gardeners.
Your level of depth that you want to take your polycultures is entirely your choice, so don’t feel overwhelmed! The point I want to make here is that even a single 4’x8’ veggie bed can benefit from polycultures.
For the sake of building soil biodiversity, I will stick to talking about polycultures for smaller, backyard annual vegetable gardens. Edible forest gardens and fruit tree guilds – two amazingly cool permaculture techniques – are entirely related to our discussion here, but deserve their own separate post.
To plant a polyculture takes a bit of know-how in terms of how quickly plants grow and how big they get, but with a bit of experimenting you will gain knowledge quicker than you ever imagined. Experiment with plantings as much as you can! There are no hard rules, just guidelines. I’ve listed a few of my tips below to get you started.
Tips for Planting Polycultures in Your Annual Vegetable Garden:
- Tip 1: Mix plant families so mostly different plants are growing together. Example: If you have four garden beds and want to plant 1 brussels sprout, 1 broccoli and 2 kale (all in the Brassica family) plant one in each of the four beds rather than all together in one bed. Not only are these all taller, longer season crops that will provide a shaded understory for lettuces, spinach and other tender greens, but their biggest predator, the cabbage looper, is also more likely to be confused by the separateness and do less overall damage. Take this example and apply it to any plant family.
- Tip 2: Plant many quick-growing, shallow rooted crops. These include radishes, hakurei turnips, arugula, lettuces and other cutting greens such as mustard, mizuna, tatsoi and baby kales. These crops are quick to grow from seeds and act nicely as a living mulch, suppressing weeds and moisture evaporation. You will increase your harvest by a ton if you plant these in between and underneath larger crops! No space goes wasted.
- Tip 3: Choose species that, when planted together, provide many support functions. Support functions include: nitrogen fixation (legumes), nutrient accumulation (when taproots mine nutrients from deep within soil and bring to surface in their foliage; great examples are comfrey and dandelion greens), act as a living mulch/groundcover to suppress weeds and protect top layer of soil (creeping thyme, cutting lettuces, sweet alyssum, vining squash), act as a vertical support trellis for vining plants (corn, okra, sunflowers), and attract pollinators and provide nectar (bee balm, echinacea, and other bright perennial flowers).
- Tip 4: Harvest whole plants. Polycultures are indeed busier and more full than traditional row plantings or simple intercropping; however, they are not meant to be overcrowded and crammed to the brim. By harvesting whole plants (entire heads of lettuce rather than leaf by leaf, full heads of cabbage including outer leaves, etc) you will free up valuable air flow, space and sunlight for the other species nearby.
For a more in-depth discussion of understanding polycultures, their functions, and a whole set of guidelines on how to design your own, I highly recommend reading Gaia’s Garden: A Guide to Home-Scale Permaculture by Toby Hemenway. There are several chapters dedicated to polycultures and plant guilds.
Onto the second part of this Step 3 to building healthy soil: Cover cropping. This is an entirely different method of soil building from polycultures – but I want to expose you to the idea because not only is it entirely feasible for you to practice cover cropping in your smaller, backyard garden, you might decide it is a more straight-forward approach and prefer to use this method instead or in combination with planting polycultures. I have an entire post about cover cropping here: 4 Steps to Cover Cropping Your Organic Garden.
4. Mulch Your Garden Beds to Protect Your Soil and Add Organic Matter
I have written several posts (here and here) already that discuss mulching, basically because it is so absolutely important for the health of your garden! Mulch serves a wide variety of functions and is one of the easiest of the steps in this list to achieve.
When we cover our soil with a mulching material, lots of awesome things happen: weeds are suppressed, moisture is kept in reducing the need to water as frequently, the material breaks down over time providing valuable organic matter to our soils, it helps prevent soil erosion in rainstorms, it feeds the members of our Soil Food Web, and most of all, it protects the top layer of our soil from nature’s harsh elements. Most of our microbial activity is contained in the top 4 inches of soil – and when left uncovered, the hot sun dries it right out, killing all of our microbes. Ouch!
When I say “mulching material,” just to be clear, I don’t mean bags of wood chip mulch at the garden center – I mean softer, natural materials like straw or decomposed leaves. You absolutely do not want to add bagged landscape mulch to your veggie garden – not only are they laden with colorants and other chemicals, but the wood does not break down fast enough to support healthy bacterial colonies, which is what your annual vegetables crave.
Great Options for Mulching Your Organic Veggie Garden:
– Straw is an economical option because not only is it initially cheap to buy, but you can also use it for your pathways. It is good to use around baby seedlings because it will help prevent birds from nibbling at them, and it will partially break down over winter so it may be incorporated into your soil during preparation in spring. Be sure to get “straw” and not “hay,” where seed heads are present.
– Decomposed leaves, or leaf mulch, is an attractive mulching option and adds a good amount of nitrogen to the soil as it breaks down and becomes incorporated into the garden bed. Earthworms love it, and as they shred it down, their castings are laden with beneficial bacteria that are essential for annual vegetable gardens. If you have a lot of trees on your property, you could create a compost pile of leaves and make your own leaf mulch, otherwise it comes bagged at most landscape suppliers. Be aware that if you do not buy certified organic leaf mulch, the mulch you do buy could have residual pesticides – not great for us or our microbial friends.
– Living mulch is a way of mulching by growing groundcover plants with shallow root systems in between vegetable plants, not unlike cover cropping or growing polycultures! Growing living mulches takes a little more maintenance and technique (you must know what plants are acceptable to grow for living mulch and when to plant them), but anyone can do it! And if you’re already practicing polyculture planting, you probably already have the living mulch method down. Another great benefit of living mulches are their added root systems – they provide tons of extra food for microbes. Great options for living mulch are sweet alyssum, creeping thyme, creeping jenny, and arugula.
5. Chop ‘n Drop: Leave Behind All the Good Stuff
My mind always refers to old growth forests when I chop ‘n drop my gardens. In a forest, everything that grows up eventually comes down – and stays there, forever. Dead leaves, branches, insect bodies, seed pods, crumbling bark, and entire fallen trees lay to decompose on the forest floor. I recently finished reading The Hidden Forest: The Biography of an Ecosystem by Jon R. Luoma, where I was enlightened by this entire system: A dead tree lying in decomposition on the forest floor is so much more alive than a living tree. It provides habitat and a food source for a whole slew of insects and microorganisms; it holds water like a sponge, hosting mosses; and slowly breaks down adding new layers of rich, organic matter made from the very stuff that grew there in the first place.
We should mimic this natural forest system in our gardens, but in a way that makes sense for our space.
“Chop ‘n Drop” is a simple way of saying that at the end of a plant’s life cycle, you cut it at the base and leave its dropped remnants in the garden to decompose over time. Roots are also left intact to decompose and host fungal hyphae. Chop ‘n drop is an especially great practice at the end of a growing season when the dropped materials can provide a nice thick layer of insulation for the soil over the winter. In my very cold Midwest, this protection is essential!
Tips for Chop ‘n Drop to Build Healthy Soil Naturally:
Tip 1: At the end of a plant’s life cycle, or at the end of the growing season, “chop” the plant at the soil line with pruners or loppers, leaving roots in tact. Roots left underground will help prevent soil erosion, leave hyphae of mycorrhizal fungi in tact, and continue to feed microbes at the rhizosphere where much microbial activity occurs.
Tip 2: Cut all leaves off the plants and let them drop. Only do this with plants that have no signs of disease or insect infestation! Good plant leaves to let drop are greens (make sure they are free of aphids), peppers, eggplant, and brassicas (broccoli, brussels sprouts, cauliflower, etc). Be wary of tomatoes and cucurbits (squash, cucumbers, pumpkins, etc), which are susceptible to many fungal and bacterial diseases that may overwinter in your garden if left behind.
Tip 3: Compost stems and thicker, woody plant matter. These won’t fully break down into next season, and you still need good stuff to throw in your compost pile, right?
Tip 4: When thinning out your brambles such as raspberries and blackberries, leave all the old canes at the base of the plants. Their natural habitats are woody areas, so we should mimic what nature would do in the first place.
Tip 5: After you’ve chopped ‘n dropped, top your beds with a thick layer of compost, and mulch on top of that, if you have access to any. Not only will this help break everything down quicker, but it will add more mass to your beds and cover up the mess we just made.
There are a multitude of ways we can build healthy soil naturally, without machines, without synthetic fertilizers, and without much work! By mimicking nature, we help restore our soils back to their original fertility. Do you have any special ways you like to build your soil? Please comment to share!