Don’t water too much too soon

I see a lot of sprinkler systems running all the time already. Do we need to be watering lawns a lot right now?

Toni, Spokane

If you mean every day or every other day right now – no. The weather is still cool and we have been getting some rain, so soil moisture levels are not being depleted very rapidly right now. As a rule of thumb, bluegrass lawns need an inch of water, including rain, a week, so right now we should be only making up the difference between that and what nature provides. When it gets hot and our spring rains are done, then we can up the frequency and rate.

To check how much your sprinklers are putting out, set out some flat bottomed cans (pet food or tuna are perfect) on the lawn and then run your system for 15 minutes. Measure the water in the cans and calculate how long it would take to get an inch of water. One fourth of an inch in 15 minutes means you’d have to run the system for an hour a week. This may mean setting them to run every four to seven days and then long enough to get water down deep to the roots.

Several high-tech devices can help get the timing right. One is a simple moisture sensor that reads moisture levels in the air. If they are high enough, meaning it rained and the humidity is high, the sensor will switch the system off for that cycle. I cut my early spring water bill in half last year using one of these sensors. They are inexpensive and can be installed on any sprinkler system timer.

Another factor in planning watering schedules both now and later, when it gets hot, is the time of day we water. It is better to water in the morning or evening when evaporation rates are lower. On hot, sunny afternoons evaporation can take as much as half the water you are putting out before it gets to the ground. You can also damage plants when water on leaves heats up too much and scalds the leaves.

The grass isn’t greener

My lawn isn’t greening up very fast this year. What’s going on?

Emily Thomas, Spokane

For starters, we had a cold spring and everything was slow coming alive. Lawns were no exception. Beyond the weather, improper fertilization at the wrong time is probably the main reason it isn’t greening up. In the last few years, thinking has changed on when is the best time to fertilize lawns. Conventional thinking said it was spring, but many lawn experts are now recommending that lawns be given their most important fertilization in the late fall so the fertilizer will be available to the grass roots as soon as they wake up in the spring. In the spring, they now recommend the application of a slow-release fertilizer that will feed the grass over an extended period.