Observe while building soil?

Hi Jenni (and anyone else who wants to comment!),

I just bought a house on a third of an acre in Atlanta. I've committed to observing the space for a year before I make any major design decisions, but I already know that my soil is GA clay. Is there any disadvantage to doing cover crop rotations to build soil biomass during the year that I'm observing the space? Or would I potentially obscure details that I'd want to take into account in my design if I put down cover crops?

Thanks!
Kirsten

Hi Kirsten, I can only speak to what worked for me in that I tended to build my beds up on top of the clay, rather than try to transform it into something not best suited for making bricks and mud plaster. Because my land had been devastated by a hurricane I had more than an abundance of woody detritus which was/is wonderful for building hulgel beds. I'm also a stone's throw away from a regular harvest of sea weeds and at this time of year I load my truck up every time I see bags of leaves put out for curbside pick-up. These ingredients also work well in lasagna beds combined with spoiled animal bedding and of course manure and that most important ingredient, compost. Pioneer plants such a comfrey and dandelions will help bring micronutrients up from the clay and also in time break it down some. I don't think a cover crop would hurt but depending on how dense the clay is, I wonder if the benefits would be worth the effort.

I love the bags of leaves thing, I noticed some today on the way home think I will grab them tomorrow.

Hi Tim, It's good to keep in mind that leaves gathered in certain neighbourhoods might contain discarded needles and other undesirable additions. It's something I never would have thought of until I was warned but now I'm a little more selective than I used to be about where I pick up my leaves. Also, as you become an experienced leaf rustler you start to case up properties, paying particular attention to what kind of trees grow where. Mixed growth with pine will obviously give you a lot of needles which will tend to turn soil acidic, poplar leaves come with a lot of woody twiglets etc. whereas oak leaves are said to be the best. However, when it comes to organic bulk for soil anything is better than nothing in my book. Leaves in a contained pile will also make good compost given time, the chickens love to play in them in the hen-poster and they can also be used to create a worm farm. And to think that some people throw them away!

I only collect leaves from lawns that have lots of weeds growing in them... That way I'm less likely to inadvertently poison my garden -- and thus myself -- with -cides.

That's a really good point, Joseph.

My own experience growing on clay in East Tennessee suggests that cover crops can be part of the transition to good soil. I've used (and use) buckwheat, beans (various sorts -- pintos etc. -- bought by the pound at the grocery/coop), and turnips, for composting in place. To me it seems like as long as you're not wasting money or expending your energy in unpleasant ways, there's not really a downside to starting cover crops as soon as you can: they're plants like any others and won't necessarily prevent you from observing.

Hi Chip, I've heard that buckwheat is a really beneficial cover crop and I certainly like the idea of any kind of beans because of their nitrogen fixing ability. I've never heard of turnips as a cover crop before. Obviously they must work well for you and I wonder if there are any hidden benefits, other than simply the bulk they provide. Do you plant very densely in order to prevent weed growth and therefore forfeit much root growth? Or do you plant in traditional rows and till weeds in with the crop? Jenni

Hi Jenni, For me, turnips as a cover crop combine three characteristics I like. One of those is definitely the bulk that you mention, both leaves and roots. They are also quick and leafy, so they compete well and grow with minimal care. They also do well (for me, at least) on hard Appalachian clay, which is definitely not the case for all covers. I had some forage turnip seed left over from a big bag I had bought for the acreage and put some of those in where I made my garden and it worked out well. I was able to plant them fairly densely and still get the leaves I wanted. But finding something able to break into the hardpack and put organic matter was a major goal and turnips did it. I never till but I do chop up and pull weeds when they bother me (not often), but the turnips weren't too bothered. For someone with clay soil, I think they're worth considering.

That's really interesting. Thanks Chip. I don't till either so I lay all my organics on top of the soil in the fall as a mulch. Is this how you introduce the turnip bulk back into the soil, or do you compost it first? And perhaps you use the roots for table and fodder as well, that would make sense. For some reason I've never had much luck growing turnips, even though my other brassicas do fine, so the thought of what to do with a cover crop of turnips somewhat boggles my mind!

I've been giving a lot of thought to soil remediation recently. I was reading and reviewing this book: https://permies.com/t/51413/books/Building-Soil-earth-approach-Elizabeth

Anyway, if the soil is clay, I find myself agreeing with Jenni and wonder if sheet/lasagne mulching would be a more suitable way to go. The right cover crop might help, but picking the right one will depend on factors like soil nitrogen and compaction (it might be worth doing a full soil test, at which point you'll have a better idea which one to use, and what other remediations you might need). In fact, for that big a plot, I'd almost definitely want to send a soil sample to a lab.

I'd actually quite like the exercise of working out what remediations might be best on the basis of the results, so feel free to get back to me on it.

If the soil is compacted you might do better with something with a deeper tap root, like lupins. Inadequate Nitrogen might be better remediated with the right nitrogen fixer or a nitrogen-rich mulch.

What's to observe, it's Georgia clay. It's pretty much the same from Macon to Brunswick and from Columbus to Augusta. It all washed down from the Appalachians over the last few million years. Sure, there might be a sand lens here or there, and some is red and some is white, but hardpan clay is hardpan clay. If you want to turn it into soil, you need to get things drilling into it: radishes, worms, moles, etc.

This is the time to be planting radish and/or turnip along with crimson clover as a winter legume. This is the seventh winter I have been at it, and I'm now noticing that the ground has a spongy, springy feel to it, like walking on a mattress. Judging by the abundance of worm casts left at the surface, my dirt is turning into soil. When I first dug my hugels, I came across many June bug larvae, but few worms. That has turned around, and I can hardly find any grubs for the chickens, but there sure is an abundance of worms.

Other taproots, like chicory, salsify, and dandelion also work to drill into the clay.

Comfrey is my fave when it comes to tap roots, even if I only believe half of what is written about its performance as a dynamic accumulator. Certainly the roots are truly impressive and as a chop 'n drop mulch or as compost tea it takes some beating. Bees love comfrey, it will produce at least two impressive growths (can be pushed to three) and it is not an unattractive plant. It can also be used as fodder, however I don't feed it to my animals because too much can cause liver damage and possibly cancer. Daikon radish seemed to be another popular pick a few years ago but I haven't heard as much about it lately. I haven't grown it myself so wouldn't want to comment directly except to say that it certainly is an impressive looking root.

True, but the advantage of lupin over comfrey is that it's much easier to obtain and germinate bulk lupin seed than it is bulk comfrey seed. I'd be much happier broadcasting lupin seed over a third of an acre than I would comfrey, both from the perspective of cost and likely germination rate. Lupin will also fix nitrogen, although the OP may want to check the drainage first.

I love comfrey, and it has its place. I'm not convinced this is it.

As always, much depends on what you need to achieve, and that soil test might be the best place to start.

A seed mix might turn out to be a good option, at that point, but I'm not going to reach conclusions without that soil assay.

jenni blackmore wrote:That's really interesting. Thanks Chip. I don't till either so I lay all my organics on top of the soil in the fall as a mulch. Is this how you introduce the turnip bulk back into the soil, or do you compost it first? And perhaps you use the roots for table and fodder as well, that would make sense. For some reason I've never had much luck growing turnips, even though my other brassicas do fine, so the thought of what to do with a cover crop of turnips somewhat boggles my mind!

Mostly I just leave most of the turnips in the ground to compost in place. Some we pulled to eat but we got tired of them relatively quickly. Even our dog just barks at them now. When we picked, though, we just tossed the leaves down where they were growing. As John says, radishes can do this, too, but for us some often recommended taproots just don't seem to push into the clay effectively (daikon the most obvious example). Probably some experimentation is going to be in order. When the clay in the Southeast US is hard, it's really hard.

Btw, I'm not suggesting this as an alternative to laying things on top but rather as a supplement to that -- something along the lines of what Kirsten seemed to be considering.

That's just me thinking small scale. I totally agree that trying to seed a third of an acre (or even less) with comfrey would probably end up being an exercise in futility. I believe it's near impossible to start comfrey from seed, which I've always thought is kind of a good thing, given that it is equally difficult to eradicate once established. I have several large clumps around the property, one of which was inadvertently covered with a large stack (three-four feet high) of fence poles. Amazingly it was undeterred, weaving branches around and up between the poles and it still flourishes, years later. I imagine having viable seed blowing wild everywhere would create some nightmare situations.

Sounds like a good plan, Chip, especially for Kirsten's situation. I had to laugh at your dog's response to a field full of turnips. I have a wonderful picture of our dog surveying a barrow load of squash with a "You waited all summer for this!!?" look on her face.

I was hoping to be able to post an image of some winter greens I just went out to pick but the technicalities of doing this are not immediately obvious to me. Perhaps I'll be able to figure it out later. Mostly I wanted to show how well they are thriving in an old straw bale bed and a pseudo cold frame; two alternative ways of growing on hopeless soil. This relatively small strip runs along the south side of the house and was/is impenetrable sub soil left from digging the foundation, but it produces like crazy. After a summer harvest of beans, lettuce mix, sunflowers and pumpkins, it is now host to Pak Choi, Mizuma, Mache and something I call Mizugula, a happenstance of me inadvertently gathering a mix of seed. (In my defense Arugula and Mizuma look quite similar when they go to seed

The straw bales stayed relatively well intact for several years and then completely disintegrated into a wonderfully fertile mound. No complaints! The 'cold frame' is nothing more than a couple of planks to hold dirt in which can be covered to protect its contents from frost. Originally I set it up as what I call a 'hot bed': lots of very fresh chicken manure first then a sizeable buffer layer of mulch (I used leaves and straw) and finally some soil. The theory is that the manure heats the soil to facilitate winter and very early spring crops. Obviously only good for shallow rooted plants that won't reach down as far as the manure which is way too fresh to grow in. Over time the manure and the mulch layer have melded and matured into incredibly fertile, fluffy soil that produces an amazing amount of food where previously plantain was the only thing that would grow. Just a couple of options for growing in clay.

jenni blackmore wrote:Hi Kirsten, I can only speak to what worked for me in that I tended to build my beds up on top

Exactly. While the OP's question is about clay, let's, for the sake of the discussion, say that it was a rooftop or a parking lot that could not be removed. In those cases, the only thing to do is to build soil on top. Whether one hugels or sheet/lasagne mulches is a function of what you want to end up with. For clay or sand, I would not mix in the material that I was adding unless I had massive quantities since it will be consumed with little affect. Put the material on the surface and get the microbiology going as well as the earth worms. If you add a fresh mulch layer each year, the wee beasties will convert it to soil organic matter and your clay or sand "subsoil" will slo-o-ow-w-wly be converted over time. Planting cover crops and deep rooted perennials and annuals will find the minerals in the clay and sand but these won't be available to your plants without a healthy mycorrhizal population.

It seems to me that it's easier to build what you want rather than fix what's wrong.

Thanks so much for your thoughts, everyone!

I can only speak to what worked for me in that I tended to build my beds up on top of the clay, rather than try to transform it into something not best suited for making bricks and mud plaster.

Interesting - I've done this before with a variation of lasagna gardening, but in an old soccer field where I hit sandstone within 3 inches of the surface. I didn't know about hugelkultur then, so everything broke down into a gorgeous soil about 3 inches deep that required daily watering since none of the roots could go down deep.

My own experience growing on clay in East Tennessee suggests that cover crops can be part of the transition to good soil. I've used (and use) buckwheat, beans (various sorts -- pintos etc. -- bought by the pound at the grocery/coop), and turnips, for composting in place. To me it seems like as long as you're not wasting money or expending your energy in unpleasant ways, there's not really a downside to starting cover crops as soon as you can: they're plants like any others and won't necessarily prevent you from observing.

What else has been part of your transition, Chip?

This is the seventh winter I have been at it, and I'm now noticing that the ground has a spongy, springy feel to it, like walking on a mattress. Judging by the abundance of worm casts left at the surface, my dirt is turning into soil. When I first dug my hugels, I came across many June bug larvae, but few worms. That has turned around, and I can hardly find any grubs for the chickens, but there sure is an abundance of worms.

I've noticed some sponginess this week, but it's also rained 8+ inches in the past two weeks so it's hard to tell exactly what's going on. I may well have gotten a boost, soil wise, from the fact that the previous owners rented the house and it doesn't look like the tenants did much maintenance. Someone clearly loved the yard at some point, based on the overgrown oak leaf hydrangeas, ferns and Japanese maples scattered around the property. There are places where it's pure clay under the weed cover, but others where there appears to be some topsoil. I even stepped on something that might have been a mole tunnel last night.

I'd actually quite like the exercise of working out what remediations might be best on the basis of the results, so feel free to get back to me on it.

I'll definitely be sending in several soil samples, and I'd love thoughts on the results! It's just one of many things that haven't taken priority over fun things like unpacking boxes, fixing leaking kitchen faucets and making sure the mysterious extra line under the gas stove is capped properly.

Since I'm not planning on growing next season and the consensus seems to be that there's no harm to cover cropping, I think I'm inclined to put down an initial mix of crimson clover, turnips and lupin. Maybe some comfrey as well, since I do have access to a good source. I'll get some soil testing done and take steps on remediation from there based on what the results are. If things go according to plan, I'll have chickens next spring to add their manure to the mix, and then next fall I can take stock of the soil and decide whether to build up some beds or run with what I have.

Kirsten Simmons wrote:Thanks so much for your thoughts, everyone!

My own experience growing on clay in East Tennessee suggests that cover crops can be part of the transition to good soil. I've used (and use) buckwheat, beans (various sorts -- pintos etc. -- bought by the pound at the grocery/coop), and turnips, for composting in place. To me it seems like as long as you're not wasting money or expending your energy in unpleasant ways, there's not really a downside to starting cover crops as soon as you can: they're plants like any others and won't necessarily prevent you from observing.

What else has been part of your transition, Chip?

Lots of adding organic matter in the form of leaves, manure, wood chips, and weeds. Also compost and vermicompost (worms and all). It actually didn't take long -- we had some good results this year after starting in summer 2013 and are still eating tomatoes now. That may come to an end tonight, though, but the kale and collards are just firing up. But the difference is night and day between where I've been developing the soil and where I haven't. I've read clay actually tends to be high in minerals and not bad soil, once you get the organic matter built up, and that matches my experience closely.

Chip, if it's going to frost, pick all your tomatoes! Mature green tomatoes will ripen just fine in the house. The flavor is not as good as vine-ripened, but better than store-bought.

Tyler Ludens wrote:Chip, if it's going to frost, pick all your tomatoes! Mature green tomatoes will ripen just fine in the house. The flavor is not as good as vine-ripened, but better than store-bought.

Better... and cheaper! We've got all the big ones in already, it's the many small "wild" type tomatoes that are going to stop producing now that it's below freezing outside.

Kirsten, I would say go with your thoughts for cover crops. Whether they directly act to improve your soil, or just provide you with material for lasagna beds that you will build down the road in locations to be determined. Get a headstart on building up your supply of organic matter for soil building, reduce weed problems by filling the space with your selections.. I don't see a downside and I think it might help with your observations rather than hinder.

Say you plant a mix of three kinds of seeds over the whole place and you get different results around the property - those differing results might highlight things you would miss if you had not uniformly planted the area.

Say you plant a mix of three kinds of seeds over the whole place and you get different results around the property - those differing results might highlight things you would miss if you had not uniformly planted the area.

Excellent point. I shall cover crop away and report back on the results.