The Best Mulch for a Vegetable Garden

Cantaloupe plants mulched in black plastic.

The three factors to consider when choosing the best mulch for your vegetable garden are: the conditions your vegetables need to grow, the time you are willing to invest and the cost.

Organic vs. Inorganic Mulch

Inorganic mulch, such as black plastic, is ideal for large crops that flourish in higher temperature soils. Black plastic mulch reduces evaporation, makes maximum use of fertilizer by reducing leaching and produces an earlier crop. Black plastic is also inexpensive. Unfortunately, black plastic mulch does nothing to add nutrients to the soil, which is essential for the success of most vegetable gardens. It also requires irrigation to be installed under the plastic, which can be costly to set up, and regular management of the irrigation.

TIP: Our expert gardening advisor, Karen Thurber adds, "When black plastic is used in the vegetable garden it should be removed at the end of each growing season. This allows the soil to "breathe" and is an opportunity to amend soil."

Organic mulches keep the soil cooler, retain moisture and add nutrients to the soil as they decompose. Organic mulches tend to require more work to put down and need to be refreshed each year. But don't fall into the trap of growers who think that if a little works, more will work better. Over mulching has killed more vegetable gardens than can be counted.

TIP: Karen advises, "Purchasing organic mulches can be costly. Using grass clippings from your lawn or composted leaves makes an inexpensive organic mulch."

Matching Mulch to Growing Conditions

Plants require 5 conditions in which to grow: Sunlight, water, soil with nutrients, air, and room to grow. The key to choosing the right mulch for your garden requires knowledge of what your individual vegetables need to thrive, not just survive. Strawberry farmers, for instance, are great lovers of straw mulch because it suppresses weeds, keeps the strawberries clean, and the soil cool. It also adds nutrients to the soil as it decomposes. However, a common complaint is that once you use straw mulch you can expect to pull up oats and perhaps other weeds next year in the spring. Peanuts are another organic mulch that are high in nitrogen and act as a great food supply for a garden, but they can also give rise to mold or nematodes (otherwise known as roundworms). Pine needles, because of their high acidity levels, are considered by some to be the best mulch for strawberries when mixed into the soil, but would not be an ideal mulch for crops that prefer a higher pH.

Because different vegetables grow in distinct ways, the mulch you choose should provide for just that sort of growth. For instance, black plastic is the best mulch for melons, cucumbers, squash and peppers specifically because of how they grow. The mulch keeps soil temperatures high, enhances bacterial activity in the soil and is impermeable to carbon dioxide. Therefore, the carbon dioxide only escapes through the same small slits in the plastic that the plants are growing through creating thick concentrations of the gas at the base of the plants and causing them to grow faster and larger. Other organic mulches can produce relatively the same affects though they might take more ongoing effort to maintain throughout the growing season. Moreover, these organic mulches must be replaced every one to two years while heavy duty plastic can cut down on these yearly workloads,making it one of the best mulches available for certain kinds of vegetable gardens.