TechNotes Aug. 21 - Lawn Establishment, Soil Temperatures

With the optimum time for reseeding or seeding lawns in the northern United States quickly approaching, it is good time to remember the golden rule in turf establishment – success is based on seed/soil contact. Site preparation or renovation practices should be focused on providing good seed/soil contact.   

In lawn renovation a general rule in to expose 30 percent of the soil prior to seeding. This is a good guide to determining how much dethatching needs to be done. A common failure in dethatching is that not enough of the thatch is removed. Seeding into thatchy areas where soil contact is not achieved will most likely result in failure.

After preparing the site, seed is often applied with a drop spreader or rotary spreader. The site should be lightly rolled to push the seed into contact with the soil. If the site cannot be adequately prepared (or even if it is) applying seed via a slit-seeder is an effective means of getting the necessary seed/soil contact. As a general rule you want the seed incorporated into the soil to a depth of 0.25 inches. 

Many homeowners think that just spreading the seed onto an existing lawn will result in new turf plants establishing.  Without good site preparation, “throwing seed down” is a waste of time and money.

Once seeded the lawn should be watered. A common mistake by many homeowners is to stop watering too soon. In lawns established or reseeded to mixes of Kentucky bluegrass and perennial ryegrass, homeowners water until they see seedlings emerge, in this case perennial ryegrass. Often times if watering stops at this time the slower germinating Kentucky bluegrass seedlings never emerge.

Soil Temperatures