Using Compost in the Garden
Composting is nature’s way of recycling. It is one of the most powerful actions we can take to reduce our trash, address climate change, and build healthy soil. By turning food scraps and yard waste into compost, we can transform our trash into a beneficial, value-added soil amendment and use it to protect the environment.
Avid gardeners know that compost has many benefits. It Improves the structure and health of your soil by adding organic matter. In sandy soils, it can increase the moisture-holding capacity which aids the drought resistance of grass, shrubs, and flowers. In heavy soils, such as clay, compost increases the infiltration, allowing moisture to move easily into a plant’s root zone.
Compost is decomposed organic material. You can make compost at home or buy finished compost in bags or bulk at plant nurseries and home improvement centers. The decomposition of compost takes place through the work of microscopic organisms including fungi and bacteria, and larger organisms like earthworms, sow bugs, millipedes and more.
Adding compost to the soil increases the activity of soil organisms - which helps to provide nutrients to your plants over time. The nutrients in compost will be released slowly throughout the growing season, but for some plants, compost may not replace fertilizer. Lawns, vegetables and fruiting trees and shrubs often need additional fertilizer to thrive.
Apply the correct amount of compost to your work site. Adding too much compost may be harmful, especially in vegetable gardens. You can apply too much compost at one time or over several years. Too much compost in soil stunts plant growth. It also may create water pollution.
For new garden beds: Apply a 3 to 4-inch layer of compost to the soil surface and incorporate into the top 8 – 12 inches of soil with a fork, spade or tiller.
For existing garden beds: Apply a 1-inch layer of compost to the bed surface each year and incorporate into the soil.
For raised beds: Fill new beds with a three-way mix with equal parts topsoil, sand, and compost. Expect the newly filled beds to compact over time as the compost in the mix further decomposes. Don’t fill raised beds with compost by itself. Compost lacks the mineral component of earthen soil and planting mixes. Compost must be mixed with these materials to support plant growth.
Another option for raised beds is sheet composting – also known as lasagna gardening. It’s a great way to fill a new raised bed while simultaneously composting garden and kitchen waste. In this method you create layers of material that will decompose as your plants grow. It best to fill your beds in the fall, so that they get a head-start decomposing before you plant in the spring. You can read more about this method in this article from the Brooklyn Botanic Garden: https://www.bbg.org/gardening/article/make_a_lasagna_garden_in_a_raised_bed
Compost should be applied to the soils before seeding a new lawn or laying sod. Compost can also be added annually, in the spring, to existing lawns. For an existing lawn, first mow the lawn short and collect the clippings (which can be added to your home composting bin). Aerate the lawn and then apply about ¼ inch of compost over the grass. You can spread grass seed over the compost to create a denser stand of turf.
Add a 1-inch layer of compost around existing perennials and herbs in the spring, and top-dress annuals with compost after planting.
For information about creating compost at home, read this information from Michigan State University Extension: https://www.canr.msu.edu/news/composting_a_smart_gardening_practice_to_recycle_garden_and_yard_waste