Growing grass on clay soil

[Fred The Canuck]

I have cleared an area of my yard and want to grow grass and eventually a vegetable garden. The area is 60'x70' and is all thick heavy clay. The area behind it is another plot of the same size with about 20 trees on it. The back plot drops about 6' over 100' towards my house and new area.

When it rains, the new area becomes a mucky mess with standing water for about a week before it evaporates. My lawn develops a miniature lake and I can't go near it with my mower without leaving ruts everywhere.

I'm thinking of placing a drainage ditch along the back of the area and placing weeping tile and running it to a hole I will dig. (4'x6' filled with crushed stone)

I want to add sand to the clay and mix it in prior to covering the area with 4" of topsoil. (Cover the clay with coarse sand and then use the tines on my box scraper to mix it in, followed by tilling.) My thought behind this is to allow water to soak into the now sandy clay mix. I'm worried that just placing the top soil on the undisturbed clay will just create a layer for the water to sit on, continuing my soggy saga.

Sorry for the long post.

 

[jeff9366]

I cannot quite picture your situation but…...

I believe you will be happier tilling in organic matter, rather than top soil. Can you get manure of any sort locally? What about Fall leaves? Husks from a feed mill? Wood chips as power lines are kept free?

Sand is often recommended as a clay amendment, as is gypsum, but sometimes, depending on lime level and other variables, clay and/or gypsum can change clay soil into concrete.

I would dig down 48" and see what is preventing drainage. Was the land pasture, compacted by animals?

I would consider ripping the land with a bigger tractor after you make the inspection excavation. That is a more thorough, permanent type improvement. With a 80-hp tractor and a big tooth you can subsoil 4' to 5' deep.

But I can't quite picture your conditions……….

I would consult with the local government Ag Agent and get a soil test at the same time.

 

[Rustyferrious]

I agree with Jeff, you need to find out why the water is not draining away. Is that the lowest spot in your yard? I don't think adding sand to the clay will have much effect - other than to make a muddy sandy clay mess when it rains. My soil is low-grade forest soil. mostly sand and rocks. I built raised beds for the veggie garden and filled them with a mushroom compost mix. Much easier to weed and care for - especially for older backs and knees. 4" of top soil isn't enough for a garden anyway. 8" would be min and 12" would be much better, if you really want to do the whole area. Organic material mixed into the existing soil would greatly improve it, but be prepared to keep at it for several years before putting in a garden. Raised beds are almost instantly ready for plants.

 

[dragoneggs]

I think you definitely need to make a better transition between your added topsoil and the existing clay that doesn't 'perc'. Adding sand and compost material should be a nice improvement (garden soil). Figure adding at least equal parts of sand and compost for best results. Tilling it well will be important.

While you are doing this you can check there isn't an underground spring causing your troubles. If so, make dedicated drainage for that.

Also put at least 2% (slight) slope facing the direction you want to channel the water and go from there. Your plan sounds good. Improve the absorption and drainage. Good luck!