Question
We had a house built a couple of years ago and the front tard was sodded, but the back and sides were not. They were seeded. Now the front yard as well as the back is dying. The builders did not use hardly ANY topsoil and now that the sod is reaching the EXTREMELY hard clay soil we have, it is just horrible. What can I do to soften the soil and get this under control. We live near Dayton, Ohio.  

Answer
I recommend core aerating in spring and fall. do this after the ground has dried a bit in late spring. may and september are good times.

fertilize in late spring and early fall. then fertilize one more time in late fall after the top growth has stopped but before a heavy freeze (early november). if you mow weekly in late fall, wait until you have not had to mow two weeks in a row (because the grass has stopped growing) and then fertilize. usually between halloween and thanksgiving. do not fertilize during hot summer months. always apply fertilizer to a dry lawn and water in immediately.

mow lawn tall and mow ferquently. avoid cutting the lawn below 2.5-3.5" tall (after cutting).

if you water, water infrequently, but deeply, e.g. such as once per week for 2 hours rather than daily for 15 minutes. as heavy clay can be difficult to wet deeply, you should water until runoff is noted and then stop for a few minutes. Resume until runoff again is noted. continue until you have watered enough to put down minimum 1" of water per application. 1" of water is usually applied by watering 2-3 hours at a time.

you can put straight sided cans out in the path of the sprinkler (such as tuna cans, pickle jars, etc). Water for 30 minutes and then meassure the height inside the cans. if the average is 1/4" then you need to water 4 x 30 minutes = 120 minutes (2 hours) to apply 1".

e.g.
water infrequently, but deeply when you do water. due to heavy clay you may have to stagger the watering patterns. water again before the soil dries really hard and crusts.

mow frequently and mow high. recycle clippings to the lawns. do not mow too low. always mow a lawn high.

fertilize in late spring, early fall and late fall. always apply to a dry lawn and water in immediately. do not fertilize during hot summer months.

core aerate in late spring or early fall. if you core aerate, do so before fertilizing/liming so these products can get into the core holes.


note:
core aerating is the process of removing cores of soil from the lawn and leaving them on the surface to decompose. the soil should be damp (not wet, but not bone dry either) when core aerating. too wet and the tines will clogg. too dry and the tines wont penetrate into the ground. Test with a screw driver.. if you can push it into the soil it is soft enough. It should not be wet/saturated, however. watering a few days prior to aerating is recommended.

core aerating machines can be rented from equipment rental stores. you may need a large car/van/suv to transport it and two people are recommended to lift it.

the core aerator is an oversized mower type which pull cores of soil from the lawn. the cores look like 3" long cigarettes and after you are done the lawn will look as if 1000 dogs did their business on it. the cores can be raked off if they look offensive, or you can break them up where they are with the back of a rake. You can also leave them to decompose. One piece of advice: avoid walking on the cores and pushing them into the lawn with your shoes. this is a particular problem with wet clay cores. A good idea is to rake them with a leaf rake.

The core holes open up the soil and allow oxygen, water and nutrients to enter the soil and slide down to the root zone. the grass roots can expand and core aerating is one of the best horticultural practices you can proform for your lawn. I highly recommend it.. especially on heavy clay.

P.s. don't worry about heavy clay. grass can grow on many surfaces and heavy clay is no exception.