Your lawn is looking for some attention this fall
Fertilize your lawn in early September to improve the color and vigor of the grass. When you consider a fertilizer, remember that nitrogen is the most essential nutrient, although too much nitrogen can cause excessive top growth and disease problems. In most cases, a rate of 1 pound of nitrogen per 1000 square feet of lawn is adequate. Many soils in the Chicago area have good levels of phosphorus, so your lawn probably does not need it. Some villages ban the use of phosphorus to improve water quality, as it can fuel algae growth in lakes and streams. If you only fertilize your lawn once a year, fall is the best time to fertilize. The amount of phosphorus is the middle number of the three numbers on the fertilizer bag.
Autumn is also a good time to core aerate to reduce soil compaction and thatch if you did not aerate in spring. Core aerating once a year is enough for most residential lawns with normal use. Very high-use lawns benefit from being aerated twice a year. It also provides an opportunity for overseeding to help improve and thicken up your lawn.
Keep the seed moist for good germination. Core aerating is best done when the ground is somewhat moist. Leave the soil/grass plugs on the lawn to break up and filter back down to the soil level. The plugs typically break down in seven to 14 days. Mark sprinkler heads and light fixtures in the lawn so they will not be damaged.
Protect trees against deer rubs
It is time to protect the trunks of smooth-barked trees like young maples from deer rubs. Deer rub their antlers on trees and typically use the trunks of smooth-barked trees. This can damage the bark and even kill trees if the damage goes all the way around the trunk. Wrap the trunks with hardware cloth, chicken wire or plastic snow fencing to a height of 5 feet to help protect the tree. Paper tree wrap does not provide adequate protection against deer rubs. Another option is to pound 1-inch by 1-inch wooden stakes into the ground around the tree to block access to the trunk. Leave the protection up through the end of November.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.