Mulch is any material, usually organic, placed on the soil's surface around plants. Organic materials most commonly used for mulching are leaves, grass clippings, pine straw, sawdust, wood shavings and wood chips---along with synthetic materials, mostly plastic sheeting. In temperate areas, the risk of spring frost is the main reason to mulch, and although Florida gardeners are blessed with warm weather, they too need to mulch their vegetables.
Florida Weather and Soil
In Northern Florida, mulch gives protection against unexpected springtime plunges in temperature, while in Southern Florida, mulch keeps moisture from evaporating in the hot summer sun. A special kind of mulch is used to eliminate nematodes that are found in most Florida soils.
Mulch Basics for Florida
The best mulch for Florida vegetable gardens is the mulch that decays the fastest---and when mulch decomposes, nutrients are added to your vegetables. Replace your decomposing mulch a couple times in one growing season.
Apply mulch before or after you seed or transplant seedlings. Shredded leaves decompose the fastest. Grass clippings decompose quickly too, but if you have a weedy lawn, your grass clippings will contain weed seeds. Mulch made of grass clippings should be no more than 2 inches deep.
Hay, another mulch to consider, rots quickly, but can be difficult to spread around small plants and may contain weed or grain seeds. Another alternative mulch consists of coco and rice hulls, but although they spread easily, they decay slower than shredded leaves or grass clippings.
Mulch keeps water from evaporating at the base of the vegetable plant---where water is needed. Mulching cuts down on the water you need for irrigation and the labor required to ensure that vegetable roots are kept moist but not soggy. Usually 2 inches of mulch will reduce the amount of water you need. When you irrigate, push back the edge of the mulch with a rake to help the water get to your vegetables.
Special Benefits for Vegetables
Tomatoes and other vegetables on lower branches often rot if they rest on damp soil. Mulching provides a barrier between the soil and those vegetables, stopping weeds from competing with the vegetables for nutrients and water. Since weeds won't grow through mulch, the fertilizer nourishes vegetables, not weeds---and, likewise, the water for irrigation goes to the vegetables, not the weeds.
A special type of mulch is often used in the struggle against nematodes (microscopic worms). It helps if you rotate your crops, but if your garden is overrun with nematodes, you might have to cook them under black plastic mulch: In the hottest six weeks of summer, strip your soil of plants, break up the soil, wet the soil to get the nematodes moving---and then cover the area with black plastic mulch. The temperature should remain above 130 degrees Fahrenheit under the plastic to kill the nematodes.