Big Daddy, I have some thin parts in my lawn from last summer's heat, is it a good time to throw down some seed to fill those areas in ? -JF
There are a lot of "depends" to this question. First, how big and how "thin" are the areas? Do you need to reseed the entire lawn because you shut off the sprinklers in July? Are there just a couple of small patches in the lawn, from say, dog urine? Is the lawn thin from too much shade for the variety of grass? What are the areas surrounding it like, all plush turf or weedy open fields?
If the areas are small, fist sized or under, I would say rough the surface, apply a small amount of fertilizer to the area around it and let the existing turf fill it in, quick, simple and least costly fix. The whole lawn? Treat it like you would a renovation project. Cut the turf that's there extremely short and bag up the clippings. Aerate or power rake to disturb the soil, spread a quality seed mix down, add some slow release starter fertilizer and spread your clippings back out over the area in a fine layer and keep wet. Larger areas, but not the whole yard, you can treat the same way as a total renovation, but read below for warnings. Thin from shade? Different types of grass have different light needs. The typical bluegrass turf does not like shade much and will often be very thin and sparse in those situations. Rye grass often holds up in much lower light situations and so is often recommended as a fix in those situations. That may still not yield the results you are after though as plants still will likely not crowd each other closely enough to make a lush turf. Consider alternate plant material like ferns or hostas that love those shady spots in your landscape.
Surrounded by lush, maintained turf or weed infested open fields, why does this make a difference in how I repair my lawn? Well, the difference is pre-emergent weed controls. You see, spring is the time we put down the preventative weed controls that protect us from hard to kill grassy & waxy weeds like crabgrass and clover. These function as a chemical barrier of sorts, keeping seeds from germinating up through their layer. This will include any grass seed you apply and follow with these products before the seed germinates fully. If weeds are typically not a problem in your lawn and the surrounding areas, you may be fortunate enough not to need pre-emergents as part of your arsenal. If weeds ARE typically a problem in your lawn and nearby, I would say you need to stay with a pre-emergent program, sod in your piece(s) or wait until fall to overseed. Fall, by the way, IS the preferred time to overseed when weed pressure is low and temps come back down from the long hot summer. -BD