Your
YARD AND GARDEN

Dave Robson

Most people supplement summer rainfall with sprinklers or irrigation hoses. Using a lawn or garden sprinkler isn't difficult, provided you follow a few simple rules.

Most lawns, flowers and vegetables require an inch of water throughout their growing season. Shade trees might be able to get by with less. However, bearing fruit trees will need as much.

When temperatures climb to the high 90s or 100s, plants may need two inches.

Sprinklers and irrigation hoses aren't calibrated for home use due to differences in water pressures, soil types and plant requirements. There is no way to state a correct number of hours to water plants properly.

Water pressure coming out of faucets with municipal water supplies cannot exceed 40 psi. With your typical sprinkler and 50 feet of garden hose, you may need to leave the water on for at least 90 minutes to provide an inch of rain.

For those with wells, check the rate on your pumps.

However, homeowners can calibrate their own sprinkler or hose to determine amount of water flow over a specific time.

Sprinklers vary considerably. Patterns can be oval, rectangular or circular. Nor do sprinklers discharge water uniformly. More water usually is released closer to the sprinkler. For that reason, homeowners are encouraged to overlap sprinkler patterns by one fourth.

To determine water flow rate, set the sprinkler in an open area and turn on the water. Place a small tin such as a tuna fish or cat food can approximately three-fourths the distance from the sprinkler to the outer edge of water discharge.

Most of these cans are an inch high. When full, check the time. That should give you a rough idea in the future for watering.

To measure irrigation hoses, allow them to soak for a half hour and then test the soil surrounding them. An inch of water will wet the average soil to a depth of 8 to 10 inches.

If the soil isn't moist that deep, continue soaking.

A soil probe, steel rod or sharp, straight stick can be used to test the soil's moisture. Wet soil will cling to the probe or rod much like a moist cake.

Homeowners should remember to avoid overwatering plants. Roots need oxygen as much as water and will start rotting if the soil is over-saturated.

Water timers may be a good investment. They can be set to water early in the morning when most of the water will soak in and not evaporate. Morning watering also minimizes disease problems.

David Robson is an Extension Educator, Horticulture, at the Springfield Extension Center, Cooperative Extension Service, University of Illinois. You can write to Robson in care of Illinois Country Living, P.O. Box 3787, Springfield, IL 62708. Telephone: (217) 782-6515. E-Mail: robsond@idea.ag.uiuc.edu

16 ILLINOIS COUNTRY LIVING AUGUST 1997