This article is for home gardeners who are in the business of building productive soil in problem areas. I’ve tried to make it as simple as possible, and I did my best to focus on the action you want to take instead of just giving you ideas. Everything you need to know in order to get into sheet mulching and building productive soil is all right here. If your in the right place and your ready to go then this is what you’ll need to do…
1. Chop down all existing weeds
How- using a mower, weed eater, or hand tool.
Why- creates a flat surface, returns nutrients to the soil, feeds the worms, bugs, and bacteria.
2. Amend the Soil
How- Get a soil test and amend with the recommended materials.
Why- Even though you will be building a few inches of soil on top, the majority of the nutrients your plants need to grow will come from the original (and improved) soil.
3. Stop the Weeds from Growing Back
How- Find a bulk supply of cardboard and newspaper and cover the slashed weeds with 5-6 layers of newspaper or 1-2 layers of cardboard.
Why- Most weeds will grow right through regular mulch so this step is important to keeping the weeds below the surface.
4. Bring in Bulk Organic Matter
How- Think composting, but instead of composting in a bin you’re composting directly in the garden. You will want to load-up on bulk organic matter, and try to layer on as much of it as you can. But you really will need A LOT depending on the space you want to mulch. Suppose you are going to use leaves as your mulch so, if you want to cover a 100’ by 10’ space with 6” of leaves you will need 500 cubic feet or 18.5 Cubic Yards of leaves! 6” is a good depth, but you can go as low as 4” or as high as 8” and still see good results. Once you have the bulk matter in place go for other materials that are high in nitrogen such as green grass clippings, manure, and compost. This will speed up the decomposition process.
Why- the organic matter you bring in will trap moisture and keep the original soil cool. Thus creating the perfect environment for the bacteria that give your soil life, attract thousands of worms and other bugs, and the decomposing organic matter will feed your plants for years to come.
How- you have two options when it comes to planting; seeds and transplants. If you want to use transplant then they can go directly into the original soil. You’ll just have to part the cardboard and mulch to make room for them. If you want to plant from seed then you will have to bring in topsoil. I’ve found that 3” pockets of soil get the seeds started off before their roots reach the mulch.
I would recommend that you first start with a small area to experiment. Your results will vary by location, time of year, depth, what you plant, and the materials available to you. Properly sheet mulched beds maintain high levels of soil productivity for several years without much additional labor.
You’ll know everything was done correctly when you dig into a recently sheet mulched area to find several inches of moist organic matter that has begun to decompose, patches of beneficial fungi, worms (and lots of ‘em!), soaking wet card board, and the remains of many burdensome weeds in newly enriched soil.