If I had this problem here in Houston, I would simply plant those plants that like water such as elephant ears, umbrella grass, and others. I won't bother specifying more since I'm sure because of the temperature difference between Cape Cod and Houston, that these won't apply in your case but perhaps you could research in your area and find some ground covers and perennials that like water and will grow in clay?

Clay actually has some advantage, it is high in nutrients (hence it's usual dark color) and what grows there will probably do well from my experience. What about other types of grass besides "bent grass" that might be more decorative?

If you have problems researching on the web, find a landscaping place that outfits ponds in your area and see what plants they recommend. These should grow well in your poor draining clay, I would think.

Then begin to add lots of organic material and build it up and in time, you might be able to branch out to plants that you originally had in mind.

Good luck and keep us posted.

I'm sorry to hear of your predicament. If all else fails, you could use the clay to make bricks, and use the bricks to build a kiln. Acquire a pottery wheel, and start throwing some beautiful pots to sell. For the proceeds, purchase loam to replace the clay. I'm teasing, of course, at least halfway teasing......

Came across a thread in the Garden Forum (link below). Scroll down to Zeedman's first post that addresses a similar situation to yours regarding compacted clay. Hope this is helpful.

Here is a link that might be useful: Anyone use composted horse manure?

Thanks elphaba and marquette. I actually thought of a willow tree and water loving plants, but I really want a paperbark maple tree so I guess we will wait three years. Marquette, did you by any chance go to Marquette Univ. where I went? We have a Dunkin Donuts right around the corner so I guess I will be hauling coffee grounds again. They think I am crazy but have been very accomodating. Will let everyone know how long it takes. Janet

How long it will take organic matter to change your clay soil enough depends on many factors, how much organic matter is added to the clay but also how active a Soil Food Web you have. If you must build that, the SFW, from scratch the whole process will take longer and with standing water, or water saturated soil that will also mean a longer time frame since your clay soil is anaerobic and the SFW needs aerobic conditions to work.

kimmsr, so how would you suggest that we get the air into the soil or do we just need to wait until it evaporates? And how long might that take, keeping in mind that the water never went down in 72 hours now. We plan to start with 4" of a really good compost and then all the leaves we can get (mulched) and then I'm not sure what else we can scrounge. I have seen people offer hay and straw on freecycle. Would that be good? Thanks for your help. Janet

janet,
What happens if you manage to dig a deep hole, does the water get below that clay layer and eventually sink away? If that is the case, you might want to educate yourself a bit about drainage methods and ways to let that water out of your yard. I only mention this since you talked about layers on your site.

hay and straw are good as well as leaves and compost. When you say get (mulched) I'm not sure what you mean but it is not necessary to shred the leaves. It is nice if you can get them that way but go ahead and use whatever you can get your hands on.

Janet:

I'm not surprised that you found clay soil on the Cape - there are little pockets scattered throughout the area - but I am surprised you found a Dunkin Donuts that will give you coffee grounds!

I tried three Dunkin Donuts just north of the Sagamore Bridge and none of them would give them to me. Several of the employees understood about compost, but said they couldn't. I finally found a coffee shop in Onset Village near the Bourne Bridge that is happy to give coffee grounds.

I'm also skeptical that you're in Zone 5 - the Cape is generally considered to be Zone 7, no colder than 6b.

You might want to also post on the New England Gardening forum concerning plant material - there's a regular poster there who lives in Falmouth and I believe has mentioned having clay soil.

Claire

I actually thought of a willow tree

I would say don't plant willows, since their fibrous roots can get into all sorts of things, like septic systems, and cause serious damage.

Also, they are brittle, and large branches break easily, which can cause damage to buildings, etc.

tclynx, yes our soil will drain if we go down almost two feet to where there is a sand layer. We were hoping to not have to get into the whole excavating and draining thing (expensive, messy, etc.)but it would not hurt to bring in some experts and get their advice. Thanks for mentioning it.

Claire, our DD was great. We gave them four 5 gallon buckets and just kept rotating them. We had to be there everyday to get them, which became a pain, but we are not complaining. The manager did not understand composting at all, but as long as her employees did not have to do anything except dump the grounds in the bucket, she was willing to go along with it.

You are also right about the zone. We moved here from another part of MA which is where we lived when I first registered with the garden web forums. I just updated my profile and also realized that they had my old email address. That may have solved my problem of not getting responses sent to my email even though I always check that box. Thanks for pointing it out.

I have been to many of the forums but never realized that there was a New England Gardening forum. I will check it out.

Marquette, we will not be planting a willow tree, we won't be planting anything until our soil is fixed, at least in the backyard. We have two large perennial beds and a raised bed garden area in another part of the property which seem to be fine.

First you need to know why that water will not drain away. Hardpan?
Water Table?
A soil so dense that water cannot flow through it?
The Hardpan and dense soil are fixed with lots of organic matter mixed in the soil, but the high water table has no fix other than to raise the level of soil high enough to be above it.

If digging down two feet will cause a section of your clay topsoil to drain down into the sand under it, solution might be as simple as making a few holes that deep and filling them with sand, gravel or other well draining stuff. It will be like scattering some drains in your yard. Keep the clay covered with mulch and keep adding organic matter to that clay and eventually you will have some good planting soil. Perhaps your drain holes will become plugged with clay eventually but it could be a quick fix and once the clay soil is improved it might not be an issue anymore.

I have a few inches of sand, about a foot of clay, and then more sand.

I got a piece of rebar, it is a long piece of metal, and hammered it in and then pull it back out where ever I am going to plant so the roots don't get all soggy.

I have read that cover crops with a long taproot, such as perennial alfalfa and comfrey, do much the same job as that rebar over a period of a few years. (But they may be hard to eradicate once you're ready to plant a garden in their place.) Does anyone have experience using cover crops to break up clay or hardpan?

I am using Oilseed Radish ( gets 2 - 4' deep ) to both break up clay, add organic matter and improve drainage in my beds. You don't need to dig it up and it's not invasive.

What is oilseed radish? I have never heard of that? Is it something that would be readily available at a nursery? Do you need to grow it from seeds? Where do you get the seeds?

What you have is called a clay lens. I would plant wetland plants native to your area... think about a rain garden.

I think Joe is right. You can't really drain a clay lens because the water that you're seeing is groundwater.

The only thing that makes me scratch my head is your statement that "yes our soil will drain if we go down almost two feet to where there is a sand layer." Are you sure about that? Typically if there is a sand layer under a clay lens, that sand layer is what is transporting groundwater, which means that it too is saturated. A sand layer sandwiched between clay lenses acts like a water pipe. It almost sounds as though when you brought in the heavy machinery, you made a hole in the pipe so to speak. I've heard of that sort of thing happening before, but usually as a result of removing a lot more than a modest 4".

How close are you to the ocean? I know the Cape has some pretty serious problems with salt-water intrusion. I hope for your sake that the water that is welling up is not saline.

-Diggity

Actually a clay lens can be drained if its disturbed, and the subsoil is sandy and the ground water elevation is below the bottom of the clay layer.

Typical ground water levels fluctuate so it can be periodically wet, rather than permanently wet.

My work usually involves finding the disturbed portion of the lens and repairing it so it will hold water again to recreate a wetland, rather than draining it.

I did a Google on Oilseed Radish and a slew of sites w/information popped up.

Here're two:

Oilseed radish @ Johnny's $6/pound

http://www.johnnyseeds.com/catalog/product.aspx?category=289&subcategory=290&item=2906&ct=CM&source=googlee_oilseed_radish

At the site linked below, scroll down to see a picture of the radish taproot

Here is a link that might be useful: Michigan State: Cover crops: Oilseed Radish

Joe, I'm curious, how do you repair a broken lens? Truck in lots of clay?

Janet, when did the excavation occur? Early summer was very wet, but the past few months have been VERY dry here in the Northeast, and I imagine the water tables must be pretty low. If you did the excavation earlier this year when we had all that rain, then it might just be surface water that you are seeing. If you did it during the dry spell, that means the water you saw must be coming from a higher elevation, or it is infiltrated saltwater (saltwater is more dense than fresh water, and the difference in water pressure where the aquifer meets the ocean can elevate the groundwater tables there near the shore).

-Diggity

it depends upon how it was damaged. Often the lenses were drained on purpose using field tile. So we find the tile, bust it, plug the trench with bentonite.

If the lens was distrubed by digging a hole in it, its a bit more complicated - determining the extents of the excavation and then using a geo-liner and clay cover to restore it.

we may not even bother with trying to fix ones that have been disturbed by excavating.

Wow!!! You guys or gals are really informed, way beyond our scope of knowledge. I love these forums. I have now educated myself on a clay lens, very interesting.

diggity, I am not sure that our clay will drain. I really just presumed it. Earlier this summer we had a dry well put in close to a windowwell which usually filled with water in the Spring and would dump water into the basement. The guy who installed it mentioned to me that he had never had to go so deep to find sand so that it would drain. We probably won't know if the dry well works until the Spring rains come.

I would be surprised if the bobcat caused any problems, just don't think it weighs that much.

We are about two miles from the ocean.

We did the excavation about two weeks ago during a dry spell. We are currently experiencing rain and soggy weather, but really only about 3/4" as of yesterday. We are keeping our eyes on that sod so it does not mold.

joepyeweed, what is it that you do? Can you or anyone out there tell me who we should consult? An environmental engineer? Is there a possibilility that this could effect the structure of our home? We are currently thinking of having a hole dug down to the sand level, filling it with gravel, covering it up and observing it. Is this a bad thing to try? Would love your advice. Thanks, Janet

Naw, joepyeweed probably just stayed at a Holiday Inn Express last night. Oops!

Sorry I couldn't resist.

The continental breakfast at the holiday inn express was pretty good this morning.

I doubt the lens is a problem for house. Of course it depends upon the depth and thickness of the lens. And how the home is constructed. (Most lenses are going to be shallower and thinner than your basement construction.)

YOu can drain the lens and keep it drained by installing some field tile and a trench drain. (I personally wouldn't do that because wet pools created by lenses in a sandy substrate are valuable to wildlife.) But if you want a lawn rather than a wetland, then you need to install a tile drain.

Call a contractor.

How about trying some Birch trees? They can be handsome and I think grow in cold weather and definitely like moisture though I'm not sure they will like it if it is anaerobic.

If we find out that our yard was backfilled during construction, can we still have the clay lens? Janet

janet400, a lens would be unaffected by materials placed on top of it.

I am in Columbia County, NY and have been dealing with clay soil for at least 15 years of active planting. Our test hole for our septic system NEVER drained so I am familiar with your problem.

When I plant I dig the hole and then put compost mixed with some Gromax (which I get by small truckload every few years) in and around the new planting. In the fall I top dress with mulched leaves and use a small mantis rototiller to work in the mulch in the spring and early summer when we get a dry spell. The mantis is small enough so I can work it around some of the plantings without distrurbing them.

There are many plants that do well in clay and moist soils. I have beautiful Amsonia, hardy geraniums, siberian iris, mint, blackberry lilies, hostas, rudebeckia, shasta daisy, ajuga, pachysandra, etc. all of which seem to do OK in wet clay. I do search out internet information on plants that do well in these soils as I extend my gardens.