Sheet Mulching
by Craig Elevitch and Kim Wilkinson – Permanent Agriculture Resources
Why Mulch?
Agriculture with mulch in the tropics promotes plant health and vigor. Mulching improves nutrient and water retention in the soil, encourages favorable soil microbial activity and worms, and suppresses weed growth. When properly executed, mulching can significantly improve the well-being of plants and reduce maintenance as compared to bare soil culture. Mulched plants have better vigor and, consequently have improved resistance to pests and diseases.
“Mulch” is a layer of decaying organic matter on the ground. Mulch occurs naturally in all forests; it is a nutrient rich, moisture absorbent bed of decaying forest leaves, twigs and branches, teeming with fungal, microbial and insect life. Natural mulch serves as a “nutrient bank,” storing the nutrients contained in organic matter and slowly making these nutrients available to plants. All forms of plant life from the ground layer to shrubs and trees thrive, grow, shed organic matter, die and decay, in a complicated cycle of nutrients.
Mulch forms a necessary link in nutrient cycling vital for our soils. When mulch is absent for whatever reason, the living soil is robbed of its natural nutrient stores, becomes leached and often desiccates. Natural environments without a litter layer are usually deserts. Non-desert plants grown in bare soil require constant fertilization, nutrient amendment and water, not to mention the work required to keep the soil bare.
Sheet mulching as described here is a suggested method for controlling weeds and improving soil and plant health with mulch. The process mimics the litter layer of a forest floor.
3 & 4 can be anything you have to hand – e.g stableyard manure & bracken where we are. Spent hops (breweries give it away), municipal compost, restaurant waste, or whatever you have.
I use a couple of thicknesses of cardboard for 2, but newspaper, in a thick enough layer, works well. You can even use old cotton clothes!
Don’t wait for it to rot down. Any time between March & August you can plant potatoes straight into it. Or other tubers. Otherwise start seeds in trays, grow on in 3in pots, and plant out into the mulch when large enough. Lots of plants will grow well enough, and in the second year, when it’s all rotted down, you’ll have a good organic soil in which you can grow anything 🙂