Living in Boulder, Colo., I’m fortunate that there are composting facilities where we can take leaves, sticks and grass clippings. But it’s also a bit disheartening to know that so much carbon gold is being trucked away to a large composting facility.
These materials are one of the greatest allies in building soil fertility and ensuring an awesome spring growing season.
I’d rather keep these valuable resources on site.
Here’s what you’re supposed to do:
- Do not rent a fossil fuel powered imported machine to slice up anything that might be already living in the soil.
- Do not recycle or throw away any newspaper or cardboard you might accrue.
- Save all sorts of organic materials including leaves, grass clippings and yes, animal poop.
- Do not dig up your weeds. Instead gently layer these materials as if you were making garden lasagna 12 inches high.
In the spring, you will have very few weeds and rich, yummy soil.
Right. Such a simple solution to so many challenges that my overly complicated mind couldn’t comprehend it…until I tried it.
Sheet mulching is now one of my most commonly recommended and practiced gardening techniques. For one, it’s local. It allows you to put to good use most of the organic materials readily available in your own backyard or neighborhood, and it’s free!
It builds soil quickly, sustainably and organically. If I’m not sheet mulching every fall, I know something is wrong.
Here are more details about how the process works:
1. Place the cardboard and newspaper over the area where you want to improve the soil. If you are using newspaper, make sure it is at least 10 sheets thick. If you are using cardboard, one to two sheets deep is fine. Just make sure that the edges overlap so that sunlight does not reach the soil. You might need to visit your local grocery or liquor store to get enough materials. Just avoid using colored, glossy paper because the cardboard and newspaper act as a light barrier to the weeds and weed seeds below it. They will smother the existing weeds and grass and deprive the weed seeds of the life giving forces they need to sprout. When you till an area like this, which many people like to do, you are not only disturbing the existing beneficial soil life, you are also tilling into the soil all of the weed seeds that have accumulated over the years (many seeds can lay dormant 10 years or more just waiting for the right conditions to sprout.). Over time, the cardboard and newspaper will break down, but by then, you have built enough soil over the top of the barrier that the seeds below will eventually become worm food.
2. Begin layering the various organic materials you have collected over the top of the cardboard and newspaper between 12 and 16 inches deep. Keep in mind that it is better to have more layers of the various materials than fewer layers. What this means is that instead of having one layer of four inches of manure, one layer of four inches of leaves and one layer of four inches of grass clippings, try for one inch of leaves, one inch of manure and one inch of grass clippings and repeat until you reach your 12 inches.
The more variety of organic materials you can find the better. Consider a layer of compost or using two different types of manure. Avoid horse manure unless it has been composted for a minimum of one year (seeds are not broken down in a horses stomach and you will be planting whatever grass they were eating.). If you have a shortage of leaves, just ask your neighbors.
Plants thrive on nitrogen, potassium, phosphorus, trace minerals and the by products of the various interactions between fungi, bacteria and insects. Soil is very much alive and we want to support all of the beneficial interactions happening below our feet. Nature gains strength and resilience through diversity.
Consider this: you can find up to 1 billion bacteria in a single teaspoon of healthy soil. Healthy soil means healthy plants.
3. Make sure your sheet-mulched area stays moist throughout the winter. If it hasn’t snowed or rained in a while, hook up the hose and give it a drink.
4. In the spring, plant! If there is not enough soil on top for small seeds like carrot seeds, just add some topsoil from a little lower in the mix. Any transplants or larger seeds should be good to go right into the sheet mulch.
Laura Ruby is an avid foodie enthusiast, sniffing out fresh, local and yummy food wherever she goes. She worked as the Garden Coordinator for the Growe Foundation for the past three and a half years installing gardens and teaching garden curriculum at Boulder Valley elementary schools. She is also the founder and owner of YummyYards, an edible landscaping company, working to co-create more functioning, self-sufficient landscapes, and is a co-facilitator and teacher at the Lyons Permaculture Design Course at the Farmette. When not teaching about growing food, you can usually find her in a garden somewhere.