Anything I've left out that would help provide a better answer?
Sand is a waste of time and money IMO. I once dumped in 10tons on a very small 15x40 area of heavy clay. Then tilled it in. It’s like it never happened. I think leaf mold and any kind of humus is a way better option to help turn a clay bed around. Also sand is just small rocks that won’t help your soil retain nutrients.
I do not have much experience with clay, but the consensus seems to be to insert organic matter, not sand. So working in a lot of compost before setting up the beds via a tiller or disc, etc.. Then set up your beds and continue to use a lot of organic matter and plants (Cover crops). Enough beneficial plants and microbes, according to Dr. Elaine Igham, will turn clay or any soil into loam. Check out her work first. Then maybe some other clay farmers will have some input?
I farmed clay and clay loam soils for 10 years, so have some experience there. They are challenging - slow to warm up and dry out in the spring, and often muddy during fall harvest. Rocks add another layer of difficulty. On the plus side, clays have a high capacity for retaining plant nutrients and available water. I have to take issue with the statement attributed to Elaine Ingham that building organic matter will turn clay into loam. Soil type - clay, loam, whatever - is determined by the proportions of sand, silt, and clay, and is independent of the level of organic matter. The attached Soil Texture Triangle shows how this works. While it is undoubtedly true that building the organic matter content of a clay soil will improve it both physically and chemically, at the end of the day it will still be a clay, and will still give you some issues as a market gardener. Many no-tillers who are growing agronomic crops like corn on clay have gone to a compromise system called strip-till, where a narrow (4 to 6") strip of soil gets tilled right where the crop row will be plant ed, giving the clay an opportunity to dry out and warm up to help germination. This can be done on a small scale by removing most of the tines on a rototiller, leaving the ones where the row(s) will be. If you goal is to make a full-time living at market gardening and to be in it for the long haul, I'd suggest getting hold of the best soil you can. Not that it's impossible on rocky clay, but it will definitely be harder than it would on a nice loam or sandy loam. And this can be a hard life under the best of conditions! As for the size of the BCS, the flail mower is the power hog. How wide a mower do you want to use? The 739 will handle a 2' flail mower OK, will even cut chest-high rye if you take the recutter screen out. But if you want a wider mower, you probably should get the 749. A sickle bar mower uses much less power since it doesn't chop the crop into bits, just cuts it once. [USDA-Soil-Texture-Triangle](//muut.com/u/notillgrowers/s1/:notillgrowers:CyDu:usdasoiltexturetriangle.png.jpg)
Thanks for that response David. You remind me of an extension agent in my county that says you can’t change what you have you can only manage it.
Listen to David. Always. I don’t think Elaine is totally nuts here, though. My understanding of clay, silt, and sand is that the differences are almost entirely physical. Sand is coarse, clay is very fine. From PSU; “To put this in perspective, if a particle of clay were the size of a BB, then a particle of silt would be the size of a golf ball and a grain of sand would be the size of a chair”. With those physical diffference, of course, you get differences in water and nutrient holding capacities, but the basic theory is the same: fill the soil with enough life, humus and carbon and it should act the same as any other soil. Logically this makes sense, and Ingham has some good (at least anecdotal) evidence of such a transformation but I do think it would be (was) reckless on my part to just say go for it. David has a massive amount of experience, just thought it was worth pointing that out.
Oh, dear. We're on heavy clay here. I'm not going to tell you what the best way to approach it is, because I'm not experienced ENOUGH in no-till, but I'll tell you what I WILL be doing to our next plots given everything I've encountered and heard about via the site. Understand, we're not under immediate economic pressure when opening a new plot and, once I get the next 3/4 acre going, I'll probably redo our current plot, as well. First, we're going to get a GOOD and complete soil test done and add minerals when we plow/disk. We'll also add as much high carbon compost and raw material as I can make/get my hands on, probably an inch or so. Once that is all worked in, I'll get it relatively level, add a little more compost to the tops of the beds and tarp it for as long as possible (some sections may get six months, some a full year). We're also going to grow a seasonally appropriate cover crop in the beds before cash crops go in. If you're working smaller sections, you might be able to be a little more surgical and mineralize/amend just the beds instead of the entire pl ot while using a BCS. IF you'll be working the straight clay with a BCS, I would recommend the 853. A note about sand, drainage, and the BCS. On that scale, I assume you'll be broadforking? That has done wonders for my drainage, I'm not sure I would worry about the sand. I'm also ditching the BCS for the garden, because I'm adding a bit of carbon compost to the bed each planting/seeding (but keeping it around for other uses, because it's handy). I've got the 749 and wish I had gone for the 853 (with electric starter). My goal is to move more toward the flail mower for cover crops and the chipper/shredder. I'm even ditching the tilther, come to find out it's really just a glorified rake. If seeding with a pinpoint, you'll need a good seedbed which may necessitate it, but the jang can handle a lot less perfect texture and a little bed trash. We're also not heavy on salad greens, we grow a bit of everything. Ps. Listen to David.
I gardened on 10” of silty clay on top of grey clay. The drainage was “moderately poor,” it was slow to warm up, and you’d sink in that full 10 inches if you stepped onto a path after a heavy rain. I added at least an inch of compost every year (2/3 an acre plot, I couldn’t afford more). I added coarse sand yearly to my carrot beds, hoping to get to every bed eventually, as my carrots would rot in the ground if it was wet at all. I broadforked root beds yearly, and I installed drainage tile that drained to an 8 foot deep pit that I’d pump out. In the eight years I gardened there, things improved, but not enough to change the economics of the situation. My input costs to try to improve the soil were too high for what I was able to produce, and I still got into the fields late. I a rainy summer like we’ve had it would have been impossible to produce much of anything. Clay particles are chemically distinct from sand or silt. It’s not just a matter of size. Clay particles are flat, and I believe there are hydrogen bonds that form between the plates when they’re wet. Comp ost helps, and maybe it can change clay to loam, but the cost of the amount you’d need seems prohibitive. Before you invest your resources, time and labor, make sure there’s good drainage, otherwise it’s like you’re Sisyphus trying to push a boulder uphill.
Oh interesting. Great comments, y’all! (Makes me wish I had a farm with every soil type to gain some experience with each). I think clay soils in general deserve more airtime on the podcast as a lot of folks are dealing with them.
Just to clarify what Elaine Ingham's opinion is here: She wouldn't say that adding good compost and using cover crops would turn clay soil into loam, but into something that *behaves like* loam.
I've got a bit of experience with heavy clay, my 2 years of commercial production has been on clay that we farmers in this area joke about being able to build a house out of it. It is just straight clay. My property has both heavy clay and rocks. I have to say that I agree with Elaine. While you will not be able to change the soil itself into clay-loam with compost/cover crops, you can certainly get it to behave that way, I'm finding this to be the case myself. I would highly recommend to till in a lot of compost at the beginning, literally as much as you can without breaking the bank. Behind that keep roots in the ground as much as possible (basic no-till principle) as it is really the plants roots that will hold that structure/improve it, otherwise your carbon will burn up, disappear and you're back to square one. I would also recommend start on less land than more, especially with tough soil. The bigger you are the more you ignore the minute details and they make a huge difference.
Also, sand is something of a waste of time, often, it doesn't truly change the structure, it just fills in the air gaps that you've already got in the clay. I'd spend the money instead on compost.
I'm starting a 3000 square foot garden this month in more of a "build a house with it" clay in southwest Louisiana. I'm going to remineralize and add compost and humates with a1 time till(unless I need more down the road). I'll let you know the results in a few months.