Summer lawn watering, vegetable harvesting and flower care
Established bluegrass lawns need an inch of water a week to continue to actively grow and stay green throughout the summer. Water deeply once or twice a week rather than lightly multiple times a week. This promotes a deeper root system so the grass will hold up better to stress.
To determine how long it takes your sprinkler to deliver 1 inch of water, set out a coffee, tuna or other shallow can with straight sides and time how long it takes to fill it with an inch of water. Be consistent with your watering practices — either water on a regular basis all summer or let your grass go dormant during hot, dry periods. If your soil has lots of clay in it and water begins to run off after long periods of watering, you may need to split watering into a couple times per week.
Mowing your lawn at a height of 3 inches or more will also help the grass withstand stress and keep out weeds. I do not water my lawn and always appreciate when it begins to go dormant for the summer, requiring less mowing.
Keep the following general rules in mind when harvesting most vegetable crops. First, it is important to harvest vegetables when they are at the peak of their flavor. Younger plants and fruits are often more tender than those left on the plant longer. The length of time vegetables remain edible depends on weather conditions. High temperatures hasten maturity.
It is also important to handle them carefully during harvest time. Check the garden daily and remove any ripe, damaged or misshapen fruits. Fruits that are not easily removed from the plant, such as eggplant, should be cut with a knife. Harvest on a regular basis to encourage production. Many plants — such as cucumber, okra and zucchini — will cease production if mature fruits are not harvested.
If you want to maximize the size of your dahlia flowers, keep the main stems free of side shoots, allowing only the terminal bud to develop. This will result in one flower per stem, and is most effective when growing the large, dinner-plate-sized cultivars. The plants will need some support to prevent wind damage as well as breakage of the stems from the weight of the flowers.
Cicada killer wasps have returned to nesting in my brick driveway. They leave holes of about ½ inch between the bricks. They are harmless even though they are large and appear intimidating. Males cannot sting and females are not aggressive and unlikely to sting unless you step on one.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.