Vegetable Gardening (102 page)

In the following sections, I explain when to quench your veggies' thirst and provide information on different watering methods. I also give you tips on how to conserve water.

Knowing when your veggies need a drink

In general, most vegetables use about 1 inch of water per week (1 to 2 inches in hot, windy, dry climates). If you don't get water from rainfall, you have to supply it. Here are some general guidelines for determining when your plants need water:

Your finger is the best indicator of when the soil has dried sufficiently to rewater.
Dig down several inches into the soil; if the soil is dry to your touch 3 to 4 inches down, it's time to water.

Wilting plants can be a sign that your soil needs water.
Wilting
is when the leaves or stems of a plant droop, bend over, and look limp. These symptoms, however, can be misleading at times. Some plants, like tomatoes, peppers, and eggplants, tend to droop slightly during the heat of the day, even if the soil has enough moisture. If your plants don't stand tall and proud and the soil feels dry, add water and watch them perk up fast.

Overwatering also causes plants to wilt, so check the soil before watering. If the soil is waterlogged, roots die from lack of air. With fewer roots, plants can no longer take up the water they need from the soil, and so they wilt. Damage from insects and disease also cause wilting.

Each vegetable has a critical period when you need to be especially careful about watering.
If you slack off during these times, your crop may be ruined. Table 15-1 shows the important watering periods for different types of vegetables.

Discovering ways to water your vegetable garden

You can water your vegetable garden several different ways. This section discusses some of the basic techniques, from the simplest — furrows — to the most complicated — drip irrigation systems.

You can measure water flow by attaching an inexpensive
flowmeter
(available at hardware and garden supply stores) to your outdoor spigot. To figure out the flow rate at the spigot, turn off all the spigots and read your water meter. Then turn on the spigot serving the hose line for 1 minute. Reread the meter to find out how much water flows through the hose in 1 minute. You need about 60 gallons per 100 square feet of garden to get 1 inch of water.

Furrows

Furrows
are shallow trenches between raised beds that channel water to plant roots. This watering method is based on an old farmer technique of planting on narrow raised mounds or beds and then using furrows to water. The beds can be 1 to 3 feet apart — the wider apart they are, however, the more water you need to add. You can use a hoe to dig a furrow at planting time and then plant the seeds or transplants on top of the raised beds, in between the furrows.

When you're ready to water, fill the furrows completely with water and then wait a while, or fill them more than once so the water penetrates down as well as sideways into the raised soil. Poke around with your finger to make sure the water has penetrated the bed.

Furrows work best on level or slightly sloping ground; otherwise, the water moves too fast down the furrows without sinking in. This watering technique traditionally has been used in arid areas with clay soil, such as the Southwest, where little natural rain falls during the growing season and streams or ground water can be used in the garden. Furrows don't work well in sandy soil because the water soaks in before it can reach the end of the furrow.

Furrows aren't the most efficient way to water. Here are a few reasons:

It takes time for the water to run from one end of a mound or bed to the other.

The beginning of a row always gets more water than the end.

You have to move your hose around a lot to fill each furrow.