Watering techniques and conservation measures for your home vegetable garden

By Deborah Cavanaugh-Grant,
local food systems and small farms educator,
University of Illinois Extension

The well was dry beside the door,

And so we went with pail and can

Across the fields behind the house

To seek the brook if still it ran.

--From the poem "Going for Water" by Robert Frost

[July 14, 2012]  As you are all aware, our brooks are not running. You also know that in your vegetable garden there is a direct correlation between an adequate water supply and the quality and yield of your harvest. As it doesn't seem likely that we will have a reprieve from the drought anytime soon, I wanted to share some tips for watering your garden, as well as water-saving conservation measures.

Vegetables need about 1 inch of water per week, which is equivalent to about 63 gallons of water per 100 square feet per week during the growing season. With concerns about water conservation, it is critical that any method you choose to use applies water around the root zone of the plant. This method will result in reducing water usage by about 50 percent.

Several types of drip or trickle equipment are available. The soaker hose is probably the easiest to use, as it requires no installation. A soaker hose is a fibrous hose that allows water to slowly seep out all along its length. It is simply laid at the base of the plants and moved around the garden as needed. There are also complete kits containing attachments and PVC hose with holes to allow gradual water release. Lastly, there is the emitter-type system in which short tubes, or emitters, come off a main water supply hose and go right to the roots of the individual plants.

Using a timer with your drip hose can provide additional water conservation. A timer directs the frequency, time of day and duration of each application of water to ensure that water is not wasted. Timers may be simple, requiring the gardener to set the length of time the water will flow, or more complex timers can be set to turn the water on and off, based on the number of hours or days between watering.

Irrigate in the morning when temperatures are cool but rising. When morning watering is not possible, water your garden in the late afternoon or very early evening -- after the day's heat has passed. Water early enough that the leaves will dry before nighttime.

Mulching minimizes evaporation of water from the soil surface, reducing irrigation needed by around 50 percent. Use an organic mulch to a depth of 1-3 inches, depending upon the particle size of the mulching material (the larger the particle, the deeper the mulch that should be applied).

According to the University of Illinois publication "Watering Techniques for Home Vegetable Gardens," most vegetables require adequate moisture from the time they are seeded or transplanted into the garden, but there are critical times when they definitely require water. Here are some of the commonly grown vegetables and the developmental stages when the need for adequate soil moisture is most critical:

• Beans (including lima and snap) -- pollination, pod development and pod enlargement

• Broccoli, cabbage, cauliflower -- head development

• Tomato, eggplant, pepper -- from flowering to harvest

• Dry onions -- bulb enlargement

• Cucumbers, muskmelons, watermelons -- flowering, fruit development

• Carrots, radish, turnips -- root enlargement

• Potato -- tuber set and when the tuber is enlarging

• Sweet corn -- during silking, tasseling and ear development

[By DEBORAH CAVANAUGH-GRANT, University of Illinois Extension]