From

Location

Message

Date Posted

Pittsburgh, PA

I posted a pic in my diary. Thinking about adding french drains across the patch to help with drainage. So far I dug two trenches across the patch as a test run to see if they actually fill with water. If they do, then I’m guessing a french drain system would help. I have clay about 8-10 inches down and I believe that’s why my garden doesn’t drain well. Would love to hear opinions about my idea. BTW - I’ve added 15+ yards of compost the past two years and it doesn’t make a difference. Thanks

12/18/2018 6:54:29 PM

NE Arkansas

I'd broadfork it down to like 24" and break that clay up... I have clay and breaking it up has helped with drainage and compaction...

12/18/2018 8:17:46 PM

Orient, Ohio

I have the same issue, I raised my patch 8-10", added surface drainage, then deep subsoiled with a single shank down about 20". Last year it really helped.

12/18/2018 8:54:28 PM

Anamosa, IA BPIowegian@aol.com

Draining farm land was a big part of my job for 30 years. You will need to make sure you have grade on your trenches and a good open outlet for them so the water runs out. Otherwise, they will just hold water in and make things worse. Your trenches need to be several inches to a foot down into the impermeable layer to adequately drain the topsoil. And you probably need more than just 10" of good topsoil. Even with drains, 2 to 3 inches of soil on top of the clay could remain wet, especially as you get farther away from the drains. It would be nice to know more about the soil profile. How deep is the clay layer and what is under it. I have seen shallow clay layers over saturated sand that made the surface wet when the clay was eroded away. And dry sand layers that will drain if you break up the clay pan. Digging a test hole 3' to 5' deep might help you understand your soil better. Also, you might want to go to the NRCS website and look up the web soil survey. You can learn a lot from that.

12/18/2018 9:20:15 PM

Anamosa, IA BPIowegian@aol.com

Before you do any digging, be sure to call your state's One Call system to locate buried utilities. You wouldn't want to sink a spade into a buried electric cable, or cut a phone line.

12/18/2018 9:23:02 PM

Orient, Ohio

I should have clarified a little more. Most of my problem was from surface water running through my property from others. Routing it around my patch to the open ditch helped.

12/18/2018 10:00:07 PM

Orient, Ohio

This allowed it to dry quicker since water wasn't standing in my patch. The sub soiling helped break up the old hard pans

12/18/2018 10:02:07 PM

Pittsburgh, PA

Should have mentioned that I did run a single shank subsoiler through the patch last year and also I have broadforked the entire patch two times. My tractor had trouble sinking the subsoiler down to its maximum depth because it was so muddy and couldn’t get much traction. And my broadfork tines are only 12”. My patch sits between our old septic drain field which is on the upper side and our existing drain field oon the bottom side.

12/18/2018 10:53:41 PM

Pittsburgh, PA

Not sure what’s beneath the clay. More clay is my guess as I’m in western Pennsylvania and that’s pretty much the norm. I went out with a flashlight and my trenches are filling with water. So tomorrow I’ll have to connect the trenches and dig a spot to allow everything to run out on the low side of the patch.

12/18/2018 10:56:46 PM

San Diego, Ca.

When I initially built my patch I had clay muck and rocks to work with. My first order of work was to get a bobcat and remove a foot to foot and a half of the bad soil. Iowegian brings up a great point. Call your utility company and make sure you know where your utilities are located before digging. In my case, I called before I dug. My patch sits right over the top of my utilities so I had to be extremely careful not to dig them up. I took out as much bad soil as I was able right down to the top of the utility lines. Then brought in new soil.
After the first year growing in the patch it was obvious I had a drainage problem. I had created a giant bath tub! The soil turned black and smelled like a swamp just a couple inches below the surface. At that point I decided the only way I could remedy the problem was to put in French drains. So I dug down until I exposed the clay layer. I would have went a bit deeper but was limited because of the utility lines. I first lined the trench with a filter fabric then a thin layer of pea gravel for the drain pipe to sit on. I also lined the drain pipe with a filter sock just to make sure roots and sediment would stay out of the pipes. I laid drain pipes the length of the patch and about 8 feet apart, filled the trench with more pea gravel to cover the pipe then overlapped the filter fabric that I lined the trench with over the top of the gravel. Since my land is flat my pipes drain into what is basically a plastic trash can that is buried with the bottom about 18 below the drain pipes. Holes were cut into the sides of the can so the drain pipes protrude directly into the can. Inside the can I placed a submersible sump pump with a float that automatically operates when the water level gets high enough in the can. The output is plumbed to empty out at my street curb and taken away from the patch area. This system has worked perfectly for me. I now have excellent drainage. continued...

12/18/2018 11:05:04 PM

San Diego, Ca.

The French drain serves a dual purpose for me by draining off excess water and is a great tool to help me leach excessive salts from my soil.
Additionally, since installing the french drains I have built up my soil level nearly a foot over the years.
The french drains are one of the best things I've done to my patch.

12/18/2018 11:05:17 PM

Anamosa, IA BPIowegian@aol.com

It is good that you are higher than the existing drain field. Were all the pipes removed from the old field? If not, they could be holding some water and keeping things wet.

If there is some slope the the ground, and you have the room, it would help to install a drain uphill from the garden. One of the drain principles we used was intercepting the water before it gets to the wet spot. Gravity will make water follow the impermeable layer underground and will come to the surface where the topsoil is thin. If you can get that water out of the ground before it gets to your garden, it will help a whole lot.

I learned about checking for utilities just before I was hired by USDA. They sent me a letter asking which of several vacancies I would consider. A couple weeks later they sent out the same later but had added the Waterloo office to. Their staff had been out to check on tile installation for a big waterway. They happened to pull up to the site when the trencher hit a big natural gas pipeline. They were killed along with several of the tile crew. Never dig unless you are absolutely certain you won't hit a utility.

12/19/2018 9:55:19 AM

Johnston, Iowa

Jay - I did something similar at my old patch where the native soil was clay. I dug three trenches. I filled in the bottom of the trenches with rock and sand. My patch sloped downhill, so water would run out at the end of the trenches. After a big rain it was easy to see that the soil above the trench areas was the first part of my patch to dry out. For me, this was a lot of hard work, but also a big success!

These pics show how water would otherwise just pool in the clay that was below the soil I was growing in.

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=151825

Close Up:
http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=151826

12/19/2018 10:19:06 AM

Pittsburgh, PA

Thanks for all the comments and suggestions. The trenches collected water so I connected them and created two outlets on the bottom trench to drain everything into my yard. I think another trench or two could make all the difference but honestly not looking forward to the work ahead of me.

12/19/2018 10:19:44 PM

Pittsburgh, PA

That looks brutal Dan

12/19/2018 10:24:44 PM

Pittsburgh, PA

Not sure if old pipes were removed. There were around 50 pine trees where my garden is when we moved in 8 years ago. Removed the pines about 5 years ago. Still finding decent sized roots when digging. I’m slowly getting my soil where it needs to be but without solving my drainage issues it’s a complete waste of time.

12/19/2018 10:32:48 PM