Question
Our spreader put the fertilizer on the new sod too heavy.  It has been 4 days and we have a few burnt spots in areas where the spreader overlapped. The rest of the lawn doesn't look too bad. The tips of the grass looks a little yellowed.  The temperature has been in the 90s.

The sod is about 2 months old and we are watering every other day with a sprinkler system.
Should we be watering more to try to dilute it?  The soil turns to clay about 4"-6" down.  

Answer
Where are you located ? If the sod is Bermuda, St. Augustine, Zoysia, Bahia or other warm season grass, it is not necerssarily a bad time to fertilize and the grass should recover. Fertilize monthly through the summer months. Apply evenly and then water in immediately with plenty of water. Even so, try to avoid the hottest months.

If you are located in temperate areas and growing kentucky bluegrass, fescue or ryegrass then fertilizing in summer is not recommended. In the northern half of USA, you should fertilize in spring and fall (never when daytime temperatures are consistently above 80F). Always apply evenly and water in well.

Your best chance right now will be to water heavily for a few days to flush the root zone. Do not fertilize again for a while.

The sod may pickup as the temperatures moderate and moisture again is moderately available.

If the sod is fully rooted, then you should graudally try to change to an infrequent and deep watering pattern such as twice per week for 1 hour instead of every 2nd day (you only do this while the sod is trying to root). If the sod has not rooted yet, or has just rooted, it was a bit premature to apply fertilizer. If the sod has not rooted, continue to water frequently.

If the sod does not recover, try to get hold of a piece of extra sod, cut it into pieces and cut out the dead parts. Then relay the sod pieces into these cut outs. Water the cutouts every 2nd day until they take.

In future, I recommend meassuring out the amount of fertilizer you need before applying. Then apply at a lower (smaller holes) setting which apply less product. Run over the lawn twice (in different directions: north/south then east/west) to ensure full coverage.

If you buy regular lawn fertilizer with numbers such as 28-4-14, 29-3-4, 33-3-3, etc then use approximately 3 lbs per 1000 sq feet. This means that if your lawn is 5,000 sq feet big, use 3 x 5 = 15 lbs of the product MAX. If you buy a 45 lbs fertilizer bag, meassure 1/3 into the bucket and do not apply more than this. Apply at half strength and continue to run the bucket until everything has been applied. This is the safest way.

Continue to water for now to flush the root zone. Then gradually transition to an infrequent but deep watering pattern (water less frequently but deeper when you do water) as this is preferred for established grass.