Reseeding, rolling lawns, and crabgrass preemergence
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
Damage from last summer, turfgrass loss from winter de-icing operations or doggy spot, and grub damage this spring can lead to re-establishing turfgrass during the spring. If you’re reseeding following some grub damage, wait about one to two weeks after applying a grub insecticide before reseeding. It is perfectly safe to apply fertilizer at the time of seeding. A starter fertilizer typically has a nitrogen to phosphorus ratio of 1:1 or 1:1.5. A starter fertilizer application at seeding will prove beneficial when trying to get the young seedlings going. Typical application rates for a starter fertilizer at seeding are 1 lb. N/1000 sq. ft. Make sure to keep the seeded area moist throughout establishment.
In many cases, this may require watering several times a day. A good mulch cover will help the area stay moist so the site may be watered less frequently. Water lightly when irrigating, there is no need to see water standing or running off the site. Avoid applying herbicides this spring, i.e. no fertilizer plus crabgrass preventer or weed and feed products. Young seedlings do not tolerate herbicides very well, and the guideline is usually to wait three real mowings before applying any herbicides or in some cases at least 60 days. By real mowings, I mean you’re actually cutting significant grass, not just running over the area to trim down any weeds.
Every spring in Michigan as the snow melts there are some turf areas that are full of lumps and bumps. Some of these are just natural from the freezing and thawing cycles that we endure all winter long. Of course other bumps are due to mole hills and tunnels. Generally, I do not advocate that homeowners need to roll their lawns, but if done in moderation at the beginning of the season it may help smooth some imperfections in the lawn. Rolling will not do damage to your lawn and the soils unless you roll a lawn when it is too wet. If you’re using one of the water ballast light weight rollers, start out with about a quarter of the roller filled with water and take a pass over the lawn to see if that’s enough weight to smooth out the bumps. If not, add more water and repeat. Following this gradual increase in weight exercise will help ensure that you don’t start out too heavy and compact the soil.
Locally in the Lansing area, the forsythia is blooming and gddtracker.net is indicating that throughout the lower half of the Lower Peninsula the timing is optimum for applying a preemergence herbicide to control crabgrass.