Clay soil

I enjoyed reading your article and found it very informative.

My yard is all clay soil. You mention in your article "If you have the bucks, you can have a foot and a half of topsoil dropped on your existing lawn and then plant new grass seed and start over. Soil on top of dirt ain't bad."

I'm in the process of grading my land. My landscaper suggested adding only 4 inches of topsoil. Is that not enough?

It depends on what's underneath.

If what you are covering is 14 inches of okay stuff, then adding 4 more inches is excellent!

If what you are covering is rock solid clay, then four inches is better than 2 inches. 18 inches would be optimal, but it might make your house look like it's sinking!

Tall fescue will shoot roots down 18 inches only if there is 18 inches of stuff to shoot roots into! Most weeds will shoot roots down only two or three inches. Plus, everything uses up the water in the top few inches first. Then when that is gone, moves on to the lower soil.

One could argue to have shallow soil and then put in a sprinkler system. They could say that a sprinkler system could be cheaper than all that topsoil.

hmmm, i'm in the process of sheetmulching right now. The same principals are applied. The "okay" soil was covered with 1-3" of hay and straw, then covered with cardbord, on top of that I'm laying 4-5" of mushroom compost and topsoil. After all of that, i'm going to apply some form of mulch, most likely straw as i've taken to it's appearance. I'm hoping things will grow here. i guess i'll have to see!

I have a large lawn of hard heavy clay 400'x65'. The previous owners used it for dirt biking, so there are large areas of nothing more than clay and rubble, where the previous paths and ramps were simply flattened.

To spread a layer of topsoil is cost prohibitive, so I'm hoping a slow and easy approach using the lazy method will eventually build up a useful (if not 18") layer of soil to support a healthy lawn. I did start off with a spread of white dutch clover the spring I moved it. I'll keep this up, along with a high mower setting in the hopes of building up some soil fertility.

Any other recommendations for building up a healthy lawn using the slow and patient approach on heavy clay soil?

I have a serious lack of trees on a southwest facing lot. Too much sun! In addition to the soil/lawn revitalization, I'll be planting tree and garden beds-o-plenty over the next few years to restore something resembling a canopy to this barren desert of a yard.

i dont see clay as big problem. i spent some time on organic farm where soil was pure clay - you could make bricks straight out of it. but they use to put lot of manure and if you add mulch and with enough water you can grow most of vegetables. biggest problem is drout - if plants are young soil becomes hard like stone and roots dont have chance to grow, so without mulching dont hope for big yield. second problem are some weeds that dont have problems with growing rapidly even on poorest soil, they steal this little bit of nutrients and yield can be extremely poor.
plant potatoes. they dont mind growing in clay. and vegetables with long roots that will let nutrients go deeper like carrots, radishes, green salad... onions can also tolerate clay.
and be patient. fertility  will come with years of mulching and adding compost.

My farm is located on heavy clay soil with a high water level especially during the winter.

Twenty years ago, after buying an old homestead on the edge of the wilderness, I purchased two dump truck loads of sand before starting new gardens on old pastures.

In hindsight, think that was my best gardening investment ever. Even though at the time, the haulage fee for the sand seemed expensive and I could barely afford it.

With the yearly addition of compost, manures and mulches, the areas where the sand was added to the clay has turned into a rich soil, that also drains well.  Some of the areas especially permanent paths that never receive any soil additions are still like concrete with big fissues in the clay pact.

Was sowing rye and barley on a clay soil in october last year. They did just fine, gave us grains, mulch and soil biomass-roots. I know this is lawn forum so i think it's a good idea to prepare soil for grasses.

I had a similar problem with a plot of land, and I did the following:

Added gypsum to loosen (crack) the soil down to allow better air penetration,
as well as providing a more acceptable environment for bio-activity to thrive
in the soil.

I then let the weeds take over and grow several inches high.

Then I mowed it down, letting the mulch stay where it was.

I then let it grow again, mowed it, let the mulch stay where it was.

After 6-months I had a very good top soil forming, and with the addition
of mulch and any other organic waste, the soil has improved remarkably.