I am thinking that I should have the builder remove a good 6 to 8 inches of this clay and replace it with top soil. Is this enough of a base for my lawn and garden area?

The amount of free time/energy you have to deal with your native soil will probably dictate your choice. After many years of amending, my HORRID clay soil is now loose, dark, fertile loam. But if I were starting anew at my age, I might go for the quick/expensive route.

Also, if 6-8 inches of new soil over clay is enough, will depend on the drainage of your land ...low, poorly drained, places in lawn will flood and become a mess![been there done that]

I second the advice to double check any material sold as 'top-soil'.

I have been amending the front yard (where the bulldozer compacted the "soil" (clay) with leaves and such since last October. It is VERY hard work by hand. We will be having the rest of the backyard roto-tilled before we add topsoil into the clay in order to help with general drainage. We will be planting Eco-Turf which is a low-mow grass that has 9" deep roots.

As for your garden, you may want to build raised beds or berms. If you plan to plant trees you may have a problem. Be sure that any tree you plant is native to your area and thrives in clay. You'll still have to dig out a hole to allow for at least 3-5 years of root growth and mix in some compost and topsoil. Trust me, there is nothing worse that having trees and shrubs remain the same size as when you planted them over ten years later (they cannot be transplanted - their roots are completely girdled). You must amend the soil to plant trees and shrubs. Do stick with native trees (especially large shade trees), as non-natives are prone to disease. I'd say do not plant Maples (Japanese Maples are ok) because ALL of mine have succumbed to rotting disease (I didn't plant the Sugar Maples, they were either here for over a hundred years or self-seeded - Long Island was originally settled by New Englanders who planted Sugar Maples all over, but they are not native here). The two Red Maples that we planted 15 years ago are in horrid shape (half the size they should be). I'll be replacing them with a Tulip Tree and perhaps a Sassafras or Sycamore. Oaks thrive here as well (except when the power company does a hack job of tree pruning and then they rot from the top down).

I encountered this monster while widening my garden last year. I had to take extreme measures to defeat it.

From 030409

From 030709

Stripping the land of topsoil should be illegal. It can negatively affect not just your house, but it can cause flooding problems elsewhere as well. We have had major flooding problems all over Long Island over the past 10 years - over-development is the main cause. We already have a high water table and removing topsoil only makes it worse. Luckily my topsoil wasn't removed (I have an old house that we expanded), but it was so badly compressed that even the topsoil comes out in solid blocks.

This is SO contrary to commonly accepted correct planting instructions, I just had to point it out so not everyone comes away from this thread thinking this is the proper way to go about it!! You will not have success!

First, one should never amend individual planting holes and this is even more of an issue when dealing with heavy or clay soils. For various reasons, primarily soil interface issues, you will only create a 'bathtub' that retains excessive moisture in the amended soil, leading to lack of oxygen at the roots and eventual rot. If you need to amend, do so over the largest area you can manage - ideally the entire mature root spread.

You do not need to stick to native plants or trees that tolerate on clay soils. Any plant can be grown as long as you consider the soil and take the proper steps to plant it correctly for those conditions. In clay or heavy soils, you want to prepare a very wide but shallow, dished planting hole at least 3x the diameter of the root ball. The tree or shrub should be placed so that the root flare/top of the rootball is above the existing soil surface anywhere from 2-6 inches, depending on the size of the rootball and maturity of the plant. Backfill to the current soil level with whatever was dug out - no amendments. Use whatever amendments or improved soil you feel necessary to mound up to the top of the rootball, creating a small berm.

FWIW, of all maples, Japanese maples are some of the least tolerant of poor drainage and planting them in amended holes in clay soils is a sure recipe for death. And not all non-natives are disease prone or natives necessarily disease resistant....it depends entirely on the specific plant.

I do agree that adding quantities of organic matter - compost or composted manure, even leaves or grass clippings - is the best way to improve clay soils and this is pretty thoroughly supported by most professionals. But it takes time. Tilling is not absolutely necessary - the same effect can be achieved by simply mulching or layering with the OM but the process is slow.

You can achieve a faster planting process in clay by creating raised beds or berms, importing decent soil to do so, or you can simply follow the above and create wide, shallow and unimproved planting holes and plant high. When in doubt, it never hurts to plant high -- your plants will appreciate the effort :-)

kimmsr. Tell her how to test the soil.

Then be assured that your soil is not that bad from the git-go. It may be improved by adding loam and sand, but don't do anything before you do kimmsr's tests.

The problem with new construction soil is true compaction. It has been marched around on by people and machines when it was wet. That compacts the particles and forces air out. The easiest way to fix that is with a box blade and ripper tines. In this picture the driver has the rippers pulled up. There are 8 of them. Those suckers will loosen any soil to a good depth. Then the box blade will smooth out the surface. It should like like this when they are finished.

Let the landscaper decide whether you need more soil, loam, or sand. Let him bring it in and spread it. Bringing in "topsoil" can be a huge mistake. Typically they take that soil pulled from your foundation and label it "topsoil" to sell to someone else. In Florida, topsoil is sand whether it came from your yard or your neighbor's. In my neighborhood topsoil is white limestone rubble with a pH of 8.0. All you can get is what you can get locally. They won't go to a farm in Iowa to get top soil for you.

I REFUSE to plant these areas again until the soil is amended. The local Cornell Extension came out and said that all Maples (except Japanese) around here are prone to disease and to replace them with native trees.

I did plant a Red Oak in the clay back in 1997 and it is thriving; so is the Bloodgood Japanese Maple we planted in 1995.

Honestly, I think the Red Maples were bad trees to begin with (I bought a Littleleaf Linden from that nursery a few years ago and I could not save it - the roots were like a complex network of Celtic Knots). The purple sand cherry and Hebes were fine when I planted them though (from different nurseries).

I now plant EVERYTHING very high - like mini 1 ft high berms. But for the street trees (Red Maples) that I must replace I plan on tilling organic matter a foot deep into the clay and then plant the tree (a Tulip Tree) about a foot above grade. I am planning to amend the entire area, not just a hole for the tree, since I plan to plant shrubs as well. My mother thinks I am nuts, and she "hates" that I plant so high, but all the shrubs she plants either die or do not grow; mine are thriving so far (except that I think I have Leafminers and Juniper Scale attacking my conifers now).

I've decided that I am going to stick with planting what I know works in my yard - Oak trees, Rhododendrons and Azaleas and Andromedas. Amending soil is one thing, but having to spray all my shrubs is something I dislike very much. The oldest (supposedly) 2 Tulip trees in the country live near me, so they should be fine as well (and Sycamores and Sassafras thrive all around me).

Using a forum to base your decisions on your yard landscaping may cause grief in the long term. Stuff you do or don't do now can have major repercussions later when it will be more difficult and more expensive to fix.

It's okay to read up on it to be more knowledgeable, but using a simple 'test' found on a forum to base your yards foundation on is not wise for the average person.

Lloyd

I dream about black soil!