In spite of the boatload of snow that fell last winter, we are experiencing our third summer of extreme drought. My summer water bill is rivaling my winter heating bill as I try to keep my gardens – and myself – hydrated in the extreme heat. Granted I have more than the average number of plants/gardens, but it would be a lot worse if I didn’t practice wise watering. Water is becoming a more scarce and valuable resource. Some predict that in the near future it will be a more valuable commodity than oil. Much of treated drinking water is used to water our landscapes, so it pays to reduce our water usage and be wise about landscape watering practices at home. Here are a few tips to help you conserve water.
If at all possible water early in the morning. This gives the soil and the plant roots the chance to absorb more moisture before it evaporates in the heat of the day. The best way to ensure that the water soaks in is to use drip irrigation (soaker hoses) so that the water soaks directly into the ground. Watering by hand, although it is more time consuming, can also be effective if you direct the water to the soil surface and not the plants. If a sprinkler is your only option, try to use one that sprays as low to the ground as possible to minimize evaporation. And if it is a windy day most of the water from an overhead sprinkler will blow away. Water deeply to encourage root growth and make plants more drought resistant. Additionally mulch can help to reduce the evaporation and keep the moisture in the soil.
Ideally we use rainwater to water our plants. But don’t wait for rainfall to water your gardens; if they need water today don’t count on a forecast of rain tomorrow. (How many times have we had such a forecast only to have the rain pass right by us.) While watering in the morning is best, don’t wait if your plants are wilting or showing drought stress. If plants are showing stress, water as soon as possible. A rain barrel is great for helping us conserve rainwater, but of course you need rain to fill the barrel. One good rainfall however can fill a barrel and you’d be surprised how long that water can last you.
A vegetable garden needs one inch of rain per week. That is a lot of water; it is equivalent to 62 gallons of water for a 100 square foot garden or 20 gallons for a 4’ x 8’ raised bed. When rainfall does not supply the needed amount you will have to supply it if you want your garden to be successful. While all plants need water to grow, some – like lawns- need less than we think and others – like trees- need more.
Traditional turf grasses in Minnesota include Kentucky bluegrass, fine and tall fescues, and perennial ryegrass. Fescues offer the best drought tolerance; fine fescues simply use less water and tall fescues have a deeper root system to access water deeper in the soil. To encourage drought tolerance and rooting, water your lawn infrequently, but deeply – maybe only once or twice a week. Your lawn care practices can have a direct impact on your irrigation needs. Higher mowing height (3 inches or more) and the proper use of fertilizers will reduce your water requirements. Consider altering your lawn expectations to allow for some yellowing during periods of drought. It is very rare to have extended droughts that completely compromise the integrity of a lawn.
During periods of adequate rainfall well established trees and shrubs will need very little supplemental water. But during periods of drought trees can suffer or die without additional watering. The first sign of a need for watering for a tree or shrub is temporary wilting. During the day the leaves will wilt or droop, but at night the leaves will recover and in the morning they will return to looking normal. The wilting usually occurs in the top center canopy of the tree or shrub, so maybe hard to spot at first. Monitoring the top 6” to 9” of the soil for dryness is the best way to gauge the need for water. Water trees and shrubs with an overhead sprinkler in the early morning until the root zone is watered. The root zone reaches the width of the tree canopy to a depth of 18.” Soils will stay moist for longer periods of time in the cooler temperatures of spring and fall than in the heat of the summer, so less watering should be needed at that time. Mulching around the base of the tree will help the soil to retain the moisture.
According to meteorologists Paul Douglas and Dr. Mark Seely, drought may be more of an emerging trend in Minnesota rather than an occasional aberration. If drought is to be more of the norm than the exception, it may be time to rethink what plants we grow in our gardens and grow more drought tolerant plants.