Question
I have a 3 year old sod planted yard.  I live in central Illinois.  I have developed several patches in the yard.  I use a lawn care service that fertilizes in a 7 step process.  I also aerate in the fall. I was wondering how to fix the bare spots. Also I have no pets.  

Answer
First step would be to find out what caused the decline in order to fix it. Was it grubs (signs: dead lawn pulls up like a carpet), too much fertilizer at the wrong times (damage happened in hot months after fertilization and never recovered in fall), or mechanical damage (mower, etc)


Choose a mix of perennial ryegrass, kentucky bluegrass and fine fescues (these are hard, chewing or creeping red). Avoid tall fescue (unless you know your lawn is tall fescue) and do not use annual (italian) ryegrass. Check lables on the back of seed packages. Also make sure the package date is less than 6 months old.

I recommend loosning the top part of the soil with a rake/shovel and mixing in a 1-2" layer of good quality potting soil or compost. Then spread new grass seeds liberally. Firm down with the back of the rake to ensure good soil/seed contact. Then water in well.

You must next keep the seedbed slightly damp but never dry until germination (grass seeds sprout). This can be done by watering daily with a garden hose sprikler or a watering can. 1-2 times per day during warm days and 3 times per day during hot summer days is required. Shallow frequent waterings are required to keep seedbed moist at all time. It helps if you cover the seeds with a very light layer of straw (from haybales) if you have it available.

Until the new grass is 3-5" tall and have been mowed twice, keep watering frequently and shallowly. Then change to an infrequent and deep watering pattern (e.g. once per week for 2 hours instead of many frequent, shallow applications). The frequent shallow applications are only to be used during seed establishment.

Germination time may take from 2 to 6 weeks.

Best time for lawn renovations are spring and fall (may and september).

I also recommend these steps:
- fertilizer your lawn in late spring, early fall and late fall (may, september and late october/early november). I would not recommend fertilizing too early in spring, or during hot summer months. If your current vendor fertilizes in summer, I would ask them to skip same.
- If grubs are the problem, I would apply an insecticide against grubs in June. Preferably, use an insecticide based on the active ingredient Merit (imidacloprid). Check lable of the insecticide as there are many options. If you use Merit you only have to apply in June. Scott's Grub-Ex or Bayer Advanced Long Season Grub Control both use this ingredient. If you use other types they could damage the healthy bug populations in the lawn and I therefore strongly recommend use of one which contain Merit, only.

- Continue to aerate in the fall. This is highly benefical for the lawn.

- Mow high and mow frequently. Mulch.
Do not mow the lawn below 2.5" tall (meassured after cutting). In summer, raise mower height to 3.5" or simply keep the height 3.0-3.5" year round. This will give a greener lawn and actually less mowing (shorter mow means more frequent mowing believe it or not). It is also much healthier for the lawn.

- Water infrequently and deeply as needed during periods of draught. Except as noted above (during seed establishment) a lawn should always be watered deeply and infrequently so that the entire soil profile is wet to a dept of 8-12" deep and then not watered again until the soil dries resonably. During very hot summer months this can mean watering twice per week but otherwise once per week is ok. ALways water deeply which means typically 1.5-2 hours or more using a plastic sprinkler attached to a gardenhose with normal household water pressure. E.g. if you move the sprinkler to cover the entire lawn, make sure each area gets 1.5-2 hours. This watering pattern is crucial in developing a good, healthy lawn.

If you have an automatic sprinkler system, then watering once or twice per week for 1 hour is typically ok. Avoid frequent (daily) shallow waterings. These are only for seed establishment.

Watering as above will encourage the roots to grow deep in search of water which will then improve draugth stress symptoms etc during draughts.

If you can not water in summer, then letting the lawn go dormant is ok for the summer. It will green up in fall when cooler temperatures and moisture again becomes avialable. The healther it was before going into dormancy the better the lawn can withstand this draught dormancy:

Keeping a healthy lawn starts with:
- mow high and mow frequently
- water infrequently and deeply (except when establishing)
- fertilize lightly in spring, more heavily in fall and not during hot summer months

I hope the above gave you something to consider

(p.s. I don't believe any lawn care company can make a justification for fertilizing 7 times per year. If they do, you can do it yourself 3 times per year with better results). Lawn fertilizers are readily available at garden centers and it is fairly easy to do.