So you want to start a garden next year. Maybe you’ve landed an allotment or have been saving a particular patch of yard, but beyond that you haven’t given it much thought, yet. I mean, it’s still winter, right? Or perhaps you already have a garden, but now that the growing season’s over there hasn’t seemed like a lot to do beyond clean up. Well, believe it or not, autumn is the best time to actually begin getting ready for your spring garden, and even now in mid-December it’s not quite too late. They key lies with the soil.
Most gardeners treat soil like an inert material that one simply “pokes” plants into. For others, it’s something to be analyzed, conditioned, and somehow maximized for optimum plant nutrition, but not really seen as a living, active food web working symbiotically with the garden plants above. The fact is, soil is actually quite “alive” and has far more life going on in its dark depths than we think. Believe it or not, the amount of life found in healthy soil far outweighs the amount of life going on above it. This life – worms, fungi, microorganisms, molds, insects, etc. – can supply a well-tended garden with just about all the fertilizer the plants will need. Effortlessly. All that’s needed is a little understanding of what kind of home our subterranean friends. By adding more life to your soil right now, you’ll be well on your way towards a hugely successful garden in the spring come planting time, regardless of which type of soil you’re working with.
The Key: Adding Organic Matter
No matter where you live in Britain, adding organic matter to your soil is the key to creating a healthy, living system, both above and below the ground. Organic matter keeps soil light and fluffy, allows for water retention and proper drainage, and releases nutrients slowly, in a way that plants can maximize. More importantly, organic matter provides the optimal living space for the hordes of soil organisms your plants depend on for full and healthy growth. Lucky for us, it’s not too difficult to find the organic materials needed to create a rock star soil environment, and depending on the size of your garden, applying the materials is a breeze.
The Magic of Mulch
You’ve probably already heard of using compost in your garden beds. That rich, humusy end product of decomposition provides a quick, organic boost to soil fertility that can’t be denied. But if you’re looking to create an entire living environment for soil life to thrive in, you’ll have to do a bit more than sprinkle your beds with “black gold” from your kitchen scraps. If you’ve ever taken a walk in a forest, you’ve probably noticed the ground covered with all sorts of leaf-litter and plant debris. If undisturbed, this organic matter slowly breaks down over time, both creating a wondrously rich humus and providing the perfect living environment for the soil organisms that help plants thrive. It also protects the soil from driving rain, compaction and extremes of temperature. Mulch in your garden does much of the same thing and can provide that magical element of effortless soil fertility your plants will totally appreciate come spring.
What is Mulch?
Simply put, mulch is any organic matter that you place on top of your soil/bed. Unlike compost, you don’t mix it into your soil – you just leave it on top. It’s nature’s way of composting in place and provides all of the nutrition of compost, while leaving the soil organism undisturbed and free to do their work. Mulch can be as simple as covering your beds with a layer of leaves or straw in the fall to “put them to bed,” or as complex as the full sheet mulch approach laid out below. Either way, your soil life will benefit greatly, helping your plants to reach their full potential.
The Benefits of Mulching
- builds soil
- provides long-term, slow-release plant nutrition
- protects the soil from temperature extremes
- conserves water while promoting adequate ventilation and oxygenation of plant roots
Sheet mulching does all this plus it
- eradicates weeds
- eliminates the need for herbicides (by suppressing weeds and promoting plant health)
- eliminates the need for tilling (which ruptures soil ecology)
Sheet Mulch
Sheet mulching is perhaps the quickest and most pain-free method of creating highly fertile new beds without digging, tilling or buying soil. (It can also be used on established beds.) In its simplest form, sheet mulch consists of weed suppressing sheets (usually cardboard or newspaper) with about 24 cm of organic material set on top of it. For a quick and simple sheet mulch, simply lay down sheets of newspaper or cardboard on top of your beds (or area you’d like to create into beds) and cover those with a solid dose of autumn leaves. (If you’re doing this in a greenhouse where it won’t be getting rained on, make sure you wet everything to the consistency of a wrung-out sponge.) If you’d like to create long-term soil nutrition, new beds, or you’re working in a weed-rich environment, a layered sheet mulch will probably serve you better.
Toby’s Bomb-Proof Sheet Mulch
There are plenty of different opinions on how to make the best soil through sheet mulch, but one of my favourites comes from a friend of mine, Toby Hemenway. Out of all the styles I’ve tried, this one has given me the longest-lasting plant nutrition. It’s resource intense, to be sure, and should be done in the fall for optimal spring planting, but most of these resources can be found for free or easily purchased. You can sheet mulch you’re garden at any time, but with this method Fall/Winter is the best, since it’s easiest to plant into already decomposed sheet mulch. If you can’t find one or more of the materials, don’t worry – sheet mulch is very forgiving. As long as you have enough cardboard or newspaper and enough organic material you’ll come out with great soil.
Materials:
- cardboard or newspaper
- manure
- lots and lots of organic material (leaves, straw, rotten hay, grass clippings, stall bedding, non-cedar sawdust, wood shavings, etc.)
- whatever organic soil amendments you’ve determined your soil needs
- compost
Method:
- If you’re doing mulching in the fall before the rains have set in, water the area thoroughly the night before you intend to sheet mulch. The soil organisms that break down mulch need enough water to their business. (Once the rains have set in you don’t have to worry about this step.)
- Slash down any vegetation growing where you’d like to create your bed and/or plants that were from last season’s garden. Don’t pull anything up – weeds will just add tasty nitrogen-rich greens for the decomposers. It’s best, though, to remove any stumps or large pieces of wood.
- Add your soil amendments.
- If you have compacted or dry earth to start with, it’s a good idea to poke some holes into it with a spading fork. It’s not necessary to turn or remove the earth – we’re just aerating it, helping the moisture to penetrate and allowing for better soil critter movement. Do this over your entire mulch site.
- Add a thin layer of nitrogen-rich material. I use manure here, but you can also use fresh grass clippings or food waste. This layer helps to attract worms and burrowing insects that will help aerate your soil even further.
- Now it’s time for the sheeting to begin. Lay down your cardboard or newspaper in one continuous, light-blocking layer. (The sheets should overlap 12 cm or so to prevent weeds from getting through. Newspaper should be at least a centimetre thick.) As you lay down the sheets, wet them thoroughly with a hose being careful not to walk on them after they’re wet.
- Next, toss on another nitrogen-rich layer to persuade the worms up through the soon-to-be rotting cardboard.
- For the next layer, add 16-24 cm of bulk organic matter – leaves, straw, hay, food scraps, animal bedding – whatever your neighbourhood has lots of. In this layer it’s not so important that the materials are seed-free; another layer lies atop this one that will cause them to rot, rather than sprout. This layer should be damp, but not wet, so use your hose accordingly. (When finished it should have the consistency of a wrung-out sponge.)
- On top of this add about 2-4cm of compost. If you don’t have enough compost you can add soil mixed with compost, or, if you’re have enough time before planting to allow the mulch to compost down, manure. (If you’ll be planting directly into it you’ll need the compost/soil to provide a seed bed.)
- The final layer is 4-8 cm of weed- and seed-free organic matter (straw, wood shavings, leaves, etc.). This layer prevents any weeds from cropping up and gives that “finished” look so that your pile looks nice and neat for any fastidious neighbours. If you’ve waited until spring to do your sheet mulch and will be planting in it right away, simply move the final mulch layer to the side and plant into the compost layer.
Putting this mulch in place in the fall or winter (i.e. at least three months before planting) will ensure that you have beds ready for spring. This type of sheet mulching tends to reach its peak of fertility around after three years or so, but it’s easy to keep going. As it composts down, all you need to do is add more mulch to the top to keep the nutrients rolling. In the end, you’ll have tremendously healthy beds that will keep your garden thriving for years, organically. And while it may be helpful to add compost or other organic boosts now and then, you shouldn’t need to ever add synthetic fertilizers or herbicides – the rich living environment you’ve just created will give the plants much of what they need and put you well on your way to the garden of your dreams.