Adding a layer of protection on the top of the soil is called mulching. The most perfect example of mulching can be found in any forest where the floor is covered with twigs, leaves and dead plants, all in stages of decomposition.
Experienced gardeners mulch their soil to prevent weeds from coming up, to conserve water in the heat of the summer months, and to protect plant roots and soil health.In the summer, weed-seed-free mulches preserve scarce moisture and soil nutrients. The best weed-free mulches are leaves, compost and wood chips. A mulch of brown, organic material supports valuable fungi in the soil and green, organic material encourages good soil bacteria.
If you buy a mulch or compost that begins to spout a few seeds, stir it up with a rake or garden fork to expose the weed roots to the sun.
In the heat of summer, the surface of the ground dries almost as quickly as it is watered. Applying mulch after deep watering slows evaporation, reducing the amount of water that has to be applied.
Mulches such as black plastic and shredded rubber can be used in paths where there is little danger oftheir smothering plant roots. Stones retain heat and dry out plant roots.
In the winter, soil expands and contracts as it freezes and thaws. Mulch helps regulate soil temperature by protecting it from these extremes. Newly planted trees and shrubs are particularly vulnerable. The root deep ground takes longer to freeze if it is well watered and mulched in the fall.
Other reasons to use mulch: It makes the garden look finished, helps the soil stay loose after rain or watering, slows down erosion, protects plants from splashing water that spreads disease, and helps keep the gardeners’ shoes cleaner.
Types of Mulch
- Tree bark mulch takes 2 to 3 years to break down. It lasts longer but provides few nutrients. Use for pathways and around trees. Keep all mulches 3-inches away from tree trunks.
- Pine needles or pine straw looks attractive and stays in place. Needles should be aged to brown before applying.
= Pine bark nuggets wash away. Pine bark mulch is a soil conditioner that can also wash in a heavy rain. Avoid cedar chips because they contain terpenes that can kill plants.
- Break small twigs that fall and put them in the rock garden and in shade beds.
- Leaves, shredded with a lawnmower, are good for vegetables and flowers. They break down in 6-months, quickly improving soil quality. They support the healthiest fungal development.
- Newspaper can be laid down before applying mulch on top, but fertilize first. It breaks down in a year.
- Grass clippings decompose very quickly so they can burn annuals if they are applied too close or too deep. Use very carefully or put into the compost pile where they will help heat the pile.
- Peat moss can be used as mulch but it adds no nutrients.
- Straw is good for vegetable gardens and paths. It breaks down quickly and can blow away. Hay and straw contain seeds.
- Cocoa hulls smell good and look nice though they can mold. They should be avoided where dogs live.
- Buckwheat hulls are light and can blow away. They make an attractive mulch and add nutrients. Leaf-blowers disperse them.
- Compost mulches feed the soil. Vegetable gardens need 2-inches of nutrient rich organics each year.
- Sawdust decomposes quickly and can be difficult to water through since it crusts.- Cottonseed, soybean or alfalfa meal, applied to a lawn at the rate of 4-pounds per 100-square feet, restores soil biology.
- Fertilizer can be applied on top of loose mulch and will release when the bed is watered.