Winter composting and spring results

Asked November 9, 2018, 5:24 PM EST

Mulched leaves this week into garden, what will this mean for this spring as you know there will be no heat or turning earth over? Will I need to add something to garden to make up for whatever action will take place in spring due to fall leaf shredding?

Bay County Michigan

1 Response

Hello,

If you chopped the leaves with a mower or some sort of chipper and then worked them in, they will break down more easily. If not, they will take a little longer to break down. No additional nitrogen is recommended for dry leaves added to bare garden beds.

These are recommendations from MSU Extension, and other extensions- “collect the mulched leaves every other mowing and put them over your cleaned out vegetable beds. Apply a 3-to-6-inch layer of mulched leaves on the vegetable garden soil. This mulch will reduce the chance of topsoil erosion and will add valuable organic material that microorganisms will continue to use throughout this fall, winter and spring as shelter and food. Next spring, you can lightly turn this mulch into the soil or plant directly into it or beneath it, depending upon whether you are seeding or transplanting. Continue this practice yearly, and you will be adding valuable organic material that improves your soil’s structure and thus, its ability to hold water and air.”

If you don’t mulch or shred the leaves, then work them into the soil. Dry leaves can be plowed or tilled under in the vegetable or annual flower beds, in fall, to provide a source of organic matter. Shredding the leaves first will speed the breakdown, so that the leaves will not be visible by spring. Be sure to mix the whole leaves into the soil, rather than leaving them on top through the winter, to avoid matting of the leaves, keeping the soil too cold and wet to work in the spring.

The nutrient content of composted leaves is very small. The levels of nutrients vary somewhat from species to species. However, the nitrogen content of composted leaves on a dry basis usually varies from 0.5 to 1.0 percent. Potash amounts are in the same range. Phosphate amounts are around 0.1 percent. Increasing the organic matter content of the soil is the main benefit of incorporating composted leaves into the soil. So, do add fertilizer in spring to your soil before planting the garden. Be prepared to side dress your garden plants about 5-6 weeks later. A soil test is always the best way to calculate how much fertilizer you need. https://www.canr.msu.edu/resources/soil_test_kit_self-mailer

Lastly, shredded leaves can be used as a winter mulch to protect tender perennials through the coming harsh weather. Shredding the leaves will help prevent them from packing down as they get wet and smothering the plants that they are supposed to protect. To provide winter protection, apply a 3-6 inch layer of shredded leaves over the top of tender perennials after several hard freezes. The goal of winter mulch is to keep plants dormant through the winter, so it must be applied after the ground is cold and plants are fully dormant. The timing of application will vary from year to year with the weather.

Here is a reference for you on the subject-

https://pss.uvm.edu/ppp/articles/fallsoils.html

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