With the onset of warm weather in early March, many homeowners were tempted to fertilize and seed lawns. Fortunately, cold weather returned and lawn care practices were put on hold. March is much too early to either fertilize or control weeds in the lawn.
Fertilizing lawns in late winter is normally not beneficial to the turfgrass plants. Early fertilization can encourage lush growth during periods when cold temperature stress can still occur. Generally, fertilizers are best applied after April 1. Select fertilizers that contain slow release nitrogen sources. These will be listed on the fertilizer bag as sulfur-coated urea, methylene urea, IBDU, triazone, or as a natural organic fertilizer. Do not apply more than 1 pound of actual nitrogen per 1,000 square feet. For example, 5 pounds of a 20-5-10 fertilizer are needed to apply 1 pound of actual nitrogen.
When fertilizing, be sure to remove any fertilizer that was applied to sidewalks or driveways. Fertilizers will run off smooth surfaces very rapidly, while minimal runoff will occur on turfgrass areas. This is an important lawn maintenance practice that can help protect our water resources.
Seeding a new lawn in the spring is possible if done properly. First, the site needs to be evaluated for the need of soil amendments. Conduct a soil test and incorporate the needed soil amendments. Second, the site should be graded to slope away from buildings. Leaving depressions in the lawn will only create future problems. Third, select the right seed for the site. If you plan on having a lawn for show, select a seed mix containing improved varieties of Kentucky bluegrass. Avoid cultivars like 'Park' or 'Nugget' in these situations. If the site is shady, avoid Kentucky bluegrass and use either a fine leaf fescue or tall fescue. (Never mix the fine leaf fescues and tall fescue.) Fourth, seed the area according to proper seeding rates. Seed is applied on a 1,000 square foot basis. For example, sow 1.5 pounds of Kentucky bluegrass, 6 pounds of tall fescue, and 3 pounds of fine leaf fescue seed per 1,000 square feet. Seed will not germinate until soil temperatures are close to 65oF. Therefore, delay seeding until later in April. Fifth, apply a starter fertilizer that contains Tupersan. Tupersan will help prevent crabgrass invasion. Sixth, protect the seedbed with a straw mulch. Apply 1 bale of weed-free straw per 1,000 square feet. The straw will help prevent erosion and maintain proper moisture to the germinating seed. Finally, keep the seedbed moist with frequent light irrigation.
Weed control in the spring is a lawn care practice that should be considered carefully. If your lawn has a good dense stand of turfgrass, weed control may not be needed. However, if the lawn has a history of a crabgrass infestation, appropriate control measures are warranted. For best control of crabgrass, apply a preemergence herbicide just prior to crabgrass germination. This normally occurs when soil temperatures near 60oF. Do not try to control dandelions in the early spring. These weeds are translocating their carbohydrates upward to the leaves at this time. Herbicide applications will burn off the shoots but may not kill the root system.
Thatch control should be considered if the thatch layer is greater than 1/2 inch in depth. Power raking is a mechanical method of thatch control. Power raking can damage the turf and preemergence crabgrass herbicides should be applied after raking and thatch removal. On the other hand, core aerating the lawn will help the thatch to naturally decompose. Aeration is also less damaging to the grass.
For more information on lawn care see the following extension publications:
- Pm-172 Establishing a Lawn from Seed
- Pm-1067 Which Grass is Best for Your Lawn?
- Pm-1057 Maintenance Fertilization of Turfgrasses
- Pm-1127 Thatch Control in the Home Lawn
- Pm-1213 Mowing Your Lawn
This article originally appeared in the March 18, 1992 issue, p. 31.