Vegetable Gardening (105 page)

For more ways to save water while maintaining your gardens and flower beds, check out
Sustainable Landscaping For Dummies
by Owen Dell (Wiley).

Keeping Your Plants Cozy and Weed Free with Mulch

Mulch
is any material, organic or inorganic, that you place over the surface of soil, usually directly over the root zone of growing plants. It has many benefits depending on the type used. Mulch suppresses weeds, holds in moisture, modifies soil temperature, lessens the chances of certain diseases attacking your plants, and adds an attractive look to your garden.

Some people use compost as a mulch, but you have to remember that compost has a different purpose than mulch. Compost is added and mixed into the soil to add nutrients and increase the workability of soil (water-holding capacity, aeration, and so on). Mulch generally doesn't add nutrients, but it helps hold in the ones already in the soil and prevents undesirables from attacking your growing plants. (You can read more about compost in Chapter 14.)

You can choose from two basic types of mulch: organic and inorganic. For vegetable growers, each type of mulch has a unique purpose, as described in the following sections.

Spreading organic mulch

Organic mulch
includes grass clippings, compost, leaf mold, pine needles, shredded bark, nut shells, cotton gin waste, straw hay, grain and fruit byproducts, composted manure, mushroom compost, peat moss, and sawdust. Some of these mulches are easier to find in different parts of the country. You can even use newspaper as an organic mulch; black-and-white newspaper print is perfectly safe to use in your garden, and most colored inks are soybean based and biodegradable (see Chapter 14 for more on using newspaper as mulch).

Generally, a 2- to 4-inch layer of organic mulch, spread evenly on the ground beneath your plants, is sufficient. However, you may have to replenish the mulch during the growing season, especially in hot summer areas, because many organic mulches break down quickly.

Using organic mulch in your vegetable garden has many benefits:

It conserves water by reducing the soil temperature and evaporation. It also keeps the soil cool by buffering direct sunlight.

It prevents wild fluctuations in soil moisture levels that can really spell disaster in hot weather.

It smothers weed seeds and prevents them from germinating. Any weeds that do come up in loose mulch are easy to pull.

As the mulch breaks down, it adds nutrients and improves the texture of the soil that it covers.

Organic mulch looks good and makes the ground tidy and clean.

The following list includes some of the downsides of organic mulches. As minor as they are, they may lead you to choose one type of organic mulch over another:

Bark mulches, such as pine, are quite acidic.
So if you use them, keep a close eye on the pH level of your soil and correct it accordingly. (Chapter 14 tells you how to test soil pH.) Also, the latest trend is artificially colored mulches. I'd avoid these brightly colored mulches for your veggies, because they may contain potentially harmful chemicals that can leach into your soil. Choose natural bark mulches instead.

Grass clippings decay quickly and must be replenished often.
Fortunately, grass clippings are usually pretty abundant. But if the grass goes to seed before you cut it, you may end up with grass growing in your vegetable garden. Also, make sure that no
herbicides
(weed killers) have been used on your lawn because the residue can damage or kill vegetables; if you have your lawn treated regularly, use another type of mulch. Likewise, hay mulch often has weed seeds in it, so use cleaner straw mulch if available.

Some organic mulches — such as fresh sawdust — rob nitrogen from the soil as they break down.
You may have to add supplemental nitrogen to your vegetables if they grow mysteriously slow or start to turn yellow. (I discuss fertilizers in detail later in this chapter.)

Some organic mulches, such as peat moss or leaves, can pack down or get hard and crusty when exposed to weather.
Water may not penetrate these mulches, running off the soil instead of soaking into the roots. My suggestion is to avoid peat moss; or at least mix it with another organic mulch such as sawdust. Don't forget that peat is also darn expensive.