instead of going down for better soils think of going up,what i mean is square foot gardening in raised beds or container gardening ,smother your grass with cardboard or several layers of newspaper and amend in raised bed with compost top soil and like good materials buy the square foot gardening book or the weedless gardening bookor look into lasagna gardening all are on top of bad soil like you have.jump over to the sfg forum on here and ask questions.i like to make things easy digging into bad soil is not easy.so work on top of what you have.depth of the boxes can be varied for the paticular crop you want eg. potatoes need a deeper box than say lettuce.hey experimenting is half the fun,god blessed me here where i have excellent top soil but i am still boxing my garden ,also if you dont realize it tilling the soil brings the conditions for dormant weed seeds to germinate. ask lots of questions a lot of very bright gardeners on this site use them!!!!

I'm a no-till kind of guy so I think it's more than a little nuts to dig deeper than a tiller would go. If you want to break up the clay you could try planting something with deep roots. Alfalfa comes to mind.

I agree w/ what's already been said. This season it's still early enough to build some raised beds. This fall plant a cover crop of alfalfa, clovers, indigenous weeds. Next spring weed eat it w/ out walking in the raised beds, either rake it out and compost the green manure, or leave it there and cover w/ compost you've made this winter.

One problem I have with the hard subsoil is that it is the perfect environment for quackgrass. So being able to plow the big areas with the tractor every fall controls the quack. I agree that adding organic matter will raise the soil and soak up the water and make it breath better. One thing I have done is to add old hay or green grass or clover to the open furrow on a 3-bottom plow, that's every 4' and then cover it and plant potatoes on top. It's a bit of hard work but it seems to make happier plants! I tried the no-till heavy mulch for several years, but the quack still grew underground and mice and hornets liked the mulch and I had some damage with mice eating the carrots.

I have seen humic acid for sale in the big-box home improvement store. I would add lots and lots of that and allow it to percolate down to the clay. It will help break up the clay and provide food for fungi.

I see that you are in zone three. I'm going to guess that you're in the south somewhere. Because it gets hot and dry, I would recommend keeping your soil covered year-round to prevent the build-up of caliche in the subsoil.

Here is a link that might be useful: caliche

No, zone 3 is not in the south. Maybe I need to change some setting to show my state. Thought it was on there. I am in central Upper Michigan and zone 3 can get frost every month of the year, and we can be down to -30 in the winter. That is why I am building ghs 20 and 30 foot square pyramids and 20 foot tipis. I have several lumber piles in my yard from when my dad had a bandmill and also have nice poles in my woodlot for tipi poles. So I need some kind of layout in the ghs and the sfg'ning sounds like a good plan. But I've already spent enough on the ghs that I'm just going to mix grass klippings in my dirt this year. It is dirt that I have grown great crops on in the past. It just can get pounded down pretty hard if it rains a lot. Then using the tiller will loosen it up again. But in the gh it won't get pounded on by the rain. But it is slower to dry out in there, as I built the gh in Feb this winter on the frozen ground.

I have a half acre so I'll just work on some raised beds in the ghs. I am going thru it anyway to sift out all of the quack roots. Fortunately I plowed it good last year with the tractor.

Add organic matter to the top 6 to 8 inches of the soil you have and eventually the rest will be taken care of. The vast majority of the plants you will grow will root in the top 6 to 8 inches of soil, and that is where the aerobic bacteria are most active. The only reason you would need to be concerned about the subsoil is if drainage is a problem and then the organic matter you work in the top soil will eventually correct that.
Plowing Quack Grass just cuts the rhizomes which then produce more plants that grow and produce even more plants.

No Idea how much this will help you I made my garden in a old hay field that I now learned had been stripped of top soil years ago to build the hwy any ways the under clay was hard as a rock after a rain I would have puddles and mud forever I tilled it with the tractor pulled all the topsoil off I used a ditchwitch trencher to make trenches through the clay into the gravel bed filled them with woodchips then tilled 5 yards of woodchips and sand into the clay put my top soil back on tilled in 6 yards of compost and planted rye
sounds like a lot of work but it was just 1 day with all that equipment laying around this spring it was the first dry spot!

What I try to do with quackgrass is get the roots to the top where they will dry out. But I usually dig them out with a fork and haul the roots away. But plowing also fluffs and mixes the soil too. kimmsr, I like your idea of tilling in grass clippings as the main plan.

idaho_gardner, thanks for the link for caliche. I've always been aware that there was some calcium source that the plants were tapping into. The wild grass and hay looks healthier than other places just a few miles away. So now I am thinking my hardpan is probably doing more good than harm. It no doubt also holds the moisture from soaking down too fast. Mixing some of it with the topsoil when I plow might have the same effect as adding lime.

Your soil horizon composition is fairly common and is the result of clay percolation out of the surface inches due to disturbance by worms, bugs and rain and then settling and rebonding into a solidish layer further down. For a good garden the clay does not have to be removed, but it can't remain as a solid layer because it prevents roots from going deep to water in hot summer months. Clay in soil can be a good thing as it holds onto nutrients, but it must be mixed up with organic matter and other soil components to increase tilth so that roots can grow into it. Clay likes to stick to things such as organic particles and lime/limestone/dolomite particles. You need to mechanically break it up so that it can stick to these things, and not to itself. Adding orgainc material on top/raised beds will not help the roots penetrate the solid clay hardpan below. I tried this for 20 years (heavily ammending the top shovel depth every year) and finally got motivated this year to dig up the very much intact clay layer under that area.

The sand and gravel below the clay is good in that it lets root grow easily down to the water below. Plants mainly get their nutrients from the warm upper layers and their hot summer water from the deep layers, so you do not need to mix the deep layers of sand and gravel with organic material.

It all comes down to where you want to put the work, into digging through the clay layer and mixing it with lots of organic matter (Composted hardwood chips works wonderfully for this because of its chunky nature) or making raised beds over top. When I prep a new garden area I dig a trench through the clay and then throw in as much raw organic matter in the bottom as I can find (sticks and leaves, plus some fertilizer), mix it in and add more soil. The upper layers get heavy doses of compost and fertilizer.

A good dense cover crop of winter rye will put copious roots into the clay clods when they are mixed into better soil and help break them up further(because the initial digging creates cracks in the clods, which allows access to the roots), but the rots can't do much over top of a solid clay hardpan.

Speaking of raised bed, if you deep dig the garden to 2-3 ft and mix in adequate organic mater you will have raised the soil level by as much as a foot simply by loosening it up.

Humic acid is stabilized and does not feed fungi, it is produced by the action of fungi decomposition of lignin. It will not heol aggregat clay inless the clay is mixed up

I don't like to use wood products in my garden. Some ppl think it is negative energy while organic matter from the field is better for the garden, so I have been using grass clippings and composted old hay.

As for deep digging, that is similar to the potato farmers in the area going thru right after planting with their subsoilers. I have double dug before I have planted root crops. It's a big job on several 100' rows but it seems to be worth it in a better crop. Although roots over a foot long don't fit in the bag, but if the reach into lower moisture it is a healthier more nutritous root I think.

You can double dig a garden bed but if you do not correct the underlaying problem that made the soil that needed that double digging, adding organic matter to the soil, you will need to repeat that job again. Adding organic matter to the soil and allowing the Soil Food Web to work will get the same results, although not quite as quickly.

Professor Cocannouer, who taught biology and conservation for 50 years recommended pig weed and other weeds to break up hard pan also bring water and nutrients to shallower depths where veggies can get to them. Veggie roots can follow the deep divers and become more deeply rooted them selves when weeds are grown as parent crops. (sorta like companion cropping)

Here is a link that might be useful: Weeds: Guardians of the soil

RJ,

I've only really skimmed the article but it is reminding me of one of those links (Janong Natural Farming, I think) on the "Why I love the internet" thread, where they show the weeds growning and then smushed down serve as mulch. Or so I thought...

VERY interesting and thanks so much for sharing. Maybe I can view my spurge in a new light. I know I'll really be rethinking the planting of Four O Clocks (though they weren't mentioned) near some roses. Not only for what they're supposed to do for Japanese beetle suppression but also to let the tubers open up some soil nearby.

Not only do I appreciate what can be learned on the internet, I ESPECIALLY appreciate the conversations I can have with folks interested in the same stuff.

I start talking microbes, brews, roots, weeds, plants around my house and eyes start to glaze over or I get interruped with "Oh, look at what the dog is doing now" type comments or "Mom, you are SOOOOOOOO weird."

Many, many thanks..
Penny

My wife is pretty open to discussing my brews and other holistic methods. I found out one of my cousins who has retired and puts most of his summer into his garden lets weeds go, he cuts them down and used them for mulch when they get too big.

Has anyone tried growing deep-rooted plants to break up the subsoil? Would this alfalfa be a good choice? I'm thinking it's a little late to plant it this year, and my beds are full anyway, so grow it yearly in rotation in beds that will be fallow during the spring and early summer.

Nygardener - I use Okra for that.

This gives the root size of vegetable crops, and it's surprising how extensive they can be.

http://www.soilandhealth.org/01aglibrary/010137veg.roots/010137toc.html

I use some Yellow sweetclover planted in an oats nurse crop in April. Sweetclover is a biannual and can grow 2 years.

I also sow some Elephant Amaranthus [pigweed] in my watermelons...stripping off the lower 3 foot of leaves....I hauled a 45¾ pound watermelon in the wheelbarrow from the garden today [also a 40½ pounder]...just braggin but true. These were from a large growing variety though.

Alfalfa has extremely deep roots (sometimes more than 15 meters deep according to wikipedia. It has the added advantage of being a legume that will add nitrogen to the soil.

Thanks for all of the excellent experience sharing here!

If you have time, please consider helping out a newbie with a similar situation. You can check out my post here:

http://forums.gardenweb.com/forums/load/ohioval/msg0920035213984.html

Hi giza, I am with farmboy, go up.However if you have what farmers call "Bottom pan" then you need to break it up.
BOTTOM PAN_ every time you run over a plot with heavy equipment (car,tractor,hay wagon)you pack the top soil & sub-soil. When you plow/till you break up the top soil, but not the sub soil, if anything you compact the sub soil as you break the top soil.You now need to break the sub soil. If you can not double dig or use a turn plow, then use a pole hole digger to break though the bottom pan. Go at least 36", 48" would be better. Most beds do not have to be loose more the 18-24" for most plant to produce.

My brother dug a trench 18" deep & 36"wide, then fulled it with coffee chaff & cover it with 6" of soil. As the chaff rots he is going to fill in with the rest of the soil.
This is his plan, not mine, just telling you what he did & said.

If you are suffering drainage problems from the heavy clay, hire a hole borer and bore some holes to allow for drainage. Definately turn in compost to yout clay loam... It will work wonders.

Here is a link that might be useful: Compost: Devon Lawn Turf

Your soil horizon composition is fairly common and is the result of clay percolation out of the surface inches due to disturbance by worms, bugs and rain and then settling and rebonding into a solidish layer further down.

While there is no doubt some illuviated clay in the B horizon, the OP's overall description suggests we're looking at glacial or fluvial deposits, so I would guess the clay is the parent material and not illuvial accumulation.

Here is a link that might be useful: Landform map of Upper Central Michigan

Since I want to spend the least labor and money, I agree with those who say till as deep as possible with a good tiller. Then plant crops with deep roots: sunflower, okra, hemp, grass family (except corn), beet, turnip, carrot, salsify, parsnip, alfalfa, chicory, dandelion, red and sweet clovers, comfrey, narrow leaved plantain

Here is a link that might be useful: Building Up Soil