Linn County Master Gardener
We complained about cold soggy conditions in winter – now we are concerned about hot dry days that are predicted to last longer into the fall. Water management in the yard and garden can be a challenge with sun and wind pulling moisture up and away from where we need it. Using water efficiently will help to keep plants healthy during the summer.
It is important to stick your finger, a stick or a shovel in the soil to measure the water depth and dryness. Deep watering into the root zone encourages sturdy plants. Watering deeply – but less often – gives the plants a better reservoir of moisture to draw on as needed.
Soil types absorb water at different rates. The root zone for most trees and shrubs is in 1 to 4 feet, but for lawns it is only 8 to 10 inches. Flower beds and annual vegetables are looking for water as deep as 12 to 18 inches.
Apply water so it will soak in, not run off. Wet soil absorbs the water better than dry soil so watering the soil once then returning to water again while it is still wet lets the water soak in deeper.
Water applied with some force, or large droplets, is more likely to penetrate the soil surface than a light misting. Water close to the plants and avoid watering bare areas that could get weedy.
Hand watering can be a meditating time, and allows a gardener to inspect plants for problems on a regular basis. Hand watering delivers more water faster, but sometimes faster that soil can absorb it.
Sprinklers scatter water where it may not be needed, and also can flood some areas with too much water too fast. Water dispersed by sprinklers is lost to more evaporation than any other watering method.
Low-flow soaker hoses and drip systems deliver water directly to target root zones at a uniform rate, avoids water waste and discourages water-borne diseases.
It might take a little experimenting to determine how much water to apply in an area. Water for an hour, wait an hour, then dig into the soil to see how far it penetrated. How long did that take? Repeat: water again and dig into another spot to see how far it penetrated.
Is the water in the root zone? If not, repeat: water again and dig into another spot. If the total time needed to get into the root zone is longer that you want to take, divide the time and plan to water the needed amount over multiple days. Or install a drip system, test the soil moisture as above and set the timer.
Researchers suggest that in July and August evapotranspiration is about 2 inches per week. Try filling a bird bath as an indicator of water loss. When the water level drops an inch, apply an inch of water to the soil.
Yellow or mottled leaves can indicate too much or too little water. Dull, wilted leaves result from not enough water. Falling leaves and floppy stems may indicate too much water.
Check containers in the morning and evening. Small pots of soil dry out more quickly. Water early when the temperature is lower, the wind is low and municipal water pressure is usually higher. Early watering allows leaves to dry off, avoiding many bacterial and fungal diseases. This is especially important to prevent black spot on roses.
Water the soil, not the plants. Let the soil dry out partially between watering to allow oxygen to re-enter the soil.
If you have invested time and money in plants, invest a little more time, and possibly more money, in helping them survive the summer. At the same time, save time and money with best practices to keep the plants healthy.
Whatever watering methods you prefer, check the moisture of the soil after you irrigate to determine how effective your methods are.
