Right next to my new house I have a beautiful flat area of grass measuring about 100ft by 50ft, where I planned to start my garden. It was perfect - long summer days with 100% sun exposure, immediately near a water source, and close to my back porch. I'm in Kentucky, with good soil and great rain water.
Unfortunately, as I began digging up the grass sod I realized why the land was so flat: An owner about 10 years ago had a horse paddock in this spot, which was prepared by placing plastic waterproof tarps over the existing soil, then 4 inches of gravel, then a thin layer of sod grass. That's right - 4 inches of gravel.
So I had a guy come out here with a skid loader to clean it up. At the time, I thought the gravel was mixed with soil, and I also wanted to keep some of the sod grass since it has plenty of organic material. So he dug in to get the tarps out, then shook out most of the gravel, dirt and sod back onto the future garden area. I've since tilled the hell out of the area to smooth it out a bit. Unfortunately, as it's dried out I now realize that it's way more gravel and way less dirt than I initially thought.
So now I'm left with about 3 inches of gravel/dirt on top of the clay. Being in amongst rural cow farms, I have easy access to composted manure and figured I'd just load a bunch of manure on top and get my vegetables growing. But now I'm wondering if the gravel is just too much, and if I need to cut my losses, clear out the rest of the gravel/dirt, till up the underlying clay, and then start adding the composted manure. Or, should I just add the manure now on top and see what I successfully grow this spring/summer, and continue to amend the soil each year? The question is, will I be fighting an uphill battle for the next decade because of all this gravel? Can I use it to my advantage?
Any thoughts on this are appreciated... I'm planning on dying on this land a few decades from now, so I can be patient but I also want to do what's best long term.
Location: Cache Valley, zone 4b, Irrigated, 9" rain in badlands.
posted 3 years ago
Depends (my gold star for the day) on the nature of the gravel...
My favorite fields are clay... Because it holds the moisture and nutrition well, and is easy to work as long as I don't till when it's too wet. It's a pain to try and dig root crops because the soil hardens by fall due to compaction from irrigation and loss of the winter moisture.
My next favorite fields are sandy. Because it's so super easy to dig root crops, and easy to weed. Sucks cause I can never keep enough water on them.
My least favorite field are rocky. Because it's hard on equipment. Weeding is a pain because it interferes with smooth movement of the hoe. Harvesting root crops is problematic. Hard to tell rocks from roots.
To me, a "rocky field" is defined as rocks about 2" in diameter or larger. That's about the size that starts interfering with the operation of the roto-tiller. I generally make the effort to remove rocks about 1.5" or larger from the fields. Anything smaller is left alone. Tilling tends to bring the largest particles to the surface, so it might not be as bad as it looks.
Location: Central Texas zone 8a, 800 chill hours 28 blessed inches of rain
posted 3 years ago
Gravel will not hurt anything. In fact, it may help a bit as it mixes down into the clay to allow air/water channels. In aquaponics no soil is used at all. It is just a gravel medium that is fed nutrients through irrigation. I think your bigger concern is getting roots down into the clay so it can breath and accept organic matter.
I think you have the right idea of composted manure on top of the mix. By continuing to amend the soil and let the roots condition the clay, you will have a great garden patch in a few years. I don't think the gravel will take that away. It might be an annoyance if you are tilling a lot; but otherwise I don't see an issue. It will keep the soil aerated underneath.
Location: Danville, KY (Zone 6b)
posted 3 years ago
Thanks guys. It's relieving to hear this, as I've spent the last month coddling a few hundred seedlings indoors while also questioning whether it was all for naught if my garden proved to be a wasteland.
If anyone else has other thoughts or advice, I'd appreciate it.