March 1, 2017

Just about the best thing you can do to any garden is to cover it with mulch. By mulching you are suppressing weeds by blocking their access to light and air, retaining moisture by slowing down soil surface evaporation and adding organic matter which improves the soil as it decomposes. It also tends to keep the plants cleaner and free of disease as it prevents many fungal spores from bouncing up on the leaves as you water or when it rains.

Organic mulches include materials that used to be living such as shredded leaves, straw, grass clippings, compost, sawdust and pine needles. Inorganic mulches are such things as landscape fabrics, plastic and various size stones. The inorganic mulches also discourage weeds, even though they do not decompose and enrich the soil, they do tend to warm the soil faster in the early spring and radiate heat at night.

Organic mulches must be installed thick enough to discourage weeds coming through. Usually, 4″ to 6″. One of the best organic mulches you can use is shredded leaves. There are many shredders on the market in a variety of catalogs. One of the best is an electric model, funnel shaped that fits in a standard trash can. Leaves are raked and placed in the hopper and come out of the bottom, fill the trash can and are ready to use immediately.

If the garden was mulched over the winter, pull the mulch away from existing plants and bulbs so that the soil will warm faster. The mulch can be re-installed after the soil has warmed and the plants are actively growing. Keep mulch at least 1″ away from stems and crowns as wet mulch can cause rot.

As mentioned earlier, mulch acts as a barrier in preventing certain fungi and bacteria from splashing up from the soil when it rains, saving the leaves from a variety of diseases. As it is decomposing, the mulch provides a perfect environment for beneficial insects.

If you do not use mulch on any portion of your property, make sure there is no bare soil. Cover it with a ground cover, grasses or other plants. Bare soil loses humus and nutrients are leached away. Exposed soil, especially if tilled, can have its structure totally destroyed by rain. Covered soil is not effected.

Living mulch:

Various cover crops or green manures  planted between rows and plants also keep weeds down and add organic matter to the soil. Green manure consists of plants that are actually incorporated into the soil to not only increase organic matter but to increase fertility. A cover crop is technically different as it is normally not turned under and fully incorporated into the soil. Plants such as sweet allysum, soybeans and clover provide the same benefits as traditional mulches but they are actually a growing crop. Not only is there an aesthetic quality to growing a living mulch but many pollinators and other beneficial insects are attracted to them during the growing season.

Mulch for vegetables:

“Straw” is a collection of stems of field crops such as wheat and oats. It is popular as a mulch because it is inexpensive and readily available but it does contain weed seeds.

“Salt hay”, also known as salt marsh hay consists of grasses harvested from salt marshes on the coast of the eastern United States. The wiry stems do not mat down or rot as quickly as straw and any seeds that are present will not germinate because they require wet, saline soil. Until the 1930’s it was harvested by hand using draft horses. In colonial times it was harvested for both animal fodder and bedding as well as mulch for gardens. Salt hay makes excellent mulch as it decomposes slowly and can last several seasons. It must be 3″ to 6″ thick to be effective. It does not pack down and smother plants.

“Hay” is the term used for a wide variety of grasses that animals feed on. It usually includes seeds of both the grasses and broadleaf weeds so it is better suited for feeding livestock than for mulching your garden.

“Chopped and shredded hay and straw” comes in a 3.5 cubic foot, plastic wrapped bale and weighs about 25 pounds. It is easy to spread and easy to store. It is processed in a factory where it is chopped into short pieces and seed heads are removed. One bail can cover up to 800 square feet but you want to apply it much thicker under vegetable plants. It is especially useful around small seedlings which are normally difficult to mulch with other, coarser materials.
Traditional wood chips, bark or hardwood mulches are not preferable nor suitable for use in vegetable gardens. They tend to use the nitrogen in the soil for their own decomposition at a faster rate and they provide an environment for fungus that would not be desirable around vegetables.

For questions or comments: ron@primexgardencenter.com