The problem is the clay with no organic matter in it, not the mix. You have to break up that clay under and around and get some stuff worked into it.

Yes, and the problem is no clay in the compost mix.

I did exactly what you described a few years ago. Compost mix drained fast and dried out while the clay underneath was soggy.
Even weeds won't grow in the area where I left this top 6" of compost (with no mulch).

You'll need to get out your shovel again and mix the compost and clay together. Not easy.

You have created a "bathtub" by puttng in a mix that drains really well but not fixing the real problem, the clay you have. This is why gardeners are told to not just amend the planting hole and instead amend a much larger area. This is why gardeners are told to not replace the clay they have with just compost or sand but instead mix about 6 to 8 percent organic matter with the clay.

Here is a link that might be useful: The bathtub effect

Some are going so far as to suggest barerooting container plants to correct poor root growth and remove all possibility of soil interface problems and especially the bathtub effect.

barerooting container plants (PDF)

Also, heavy mulching (at least 6") has also been shown to help loosen clay soil.

Think you're going to have to remove the new stuff until the clay underneath has a chance to drain and get to the 'only moist' stage. Incorporating the nursery mix into soppy clay will create a disaster. Speaking from gardening in GA for over 30 years. If you dig it while wet, it will clump - huge clumps.

HTH avert another prob,
Rosie, Sugar Hill, GA

dunno that i would ever incorporate any material that contains pine bark or whatever, may be too acid, but lime was mentioned, the easiest way we deal with clay is gypsum. maybe you would have done better with mushroom compost? instead of that mix.

now i would suggest is mulch pretty heavily with spoilt hay or similar to a depth of 8"s.

we use lots of sugarcane mulch it comes cheap enough.

len

Here is a link that might be useful: lens bale garden

Thanks for the input. My "native soil" is extra bad because it's a new house, and as usual in GA our builders scraped up every speck of native soil that was there, and all we have is the subsoil clay that was super-compressed by construction machinery running over it a hundred times. This is why I didn't mix it with the good soil, it would be like mixing industrial grade play-do in. I knew about the bathtub effect, but i had hoped that about 35 square feet would be a large enough area to mitigate it. The beds sit on a slope, I am starting to think that digging some drainage ditches down the slope, while not ideal, may be a viable solution. I'm afraid even if I dig all the soil mix back out and mix it with the clay better, the water still needs a way out.

RyanK817 - I googled Bricko's nursery mix to see what it is. Looks like it's compost with some other nutrients mixed in.

"The first and most important reason Nursery Mix is so good is it starts with our premium original plant food, Compostost. Then it is enriched with Kricket Krap, dolomite lime, and 16-4-8 fertilizer. All of this is mixed well with composted pine bark, and aged before selling."

So in this case your raised beds might be considered as large container gardening, the same as potted plants on the patio. (something I learned from this forum) An immediate help might be to treat your growing medium as a version of Mel's mix or potting soil. The one time only addition of a moisture absorbing element such as expanded shale, vermiculite or perlite would retain moisture in your growing medium.

Each year you will be adding more nursery mix to replenish what has decomposed. Eventually the soil food web underneath will start incorporating the organic material.

Even with builders soil, I still recommend peope get a soil test from someplace like UMass. I have been surprised at the level of organic matter in poor soils from time to time. Sure they still needed more, but not nearly as much as I would have guessed. You are shooting for 5-10%.

Not likely to be much OM in a subsoil. GA clay is mostly kaolin, very low in K. Good point about letting it dry out before tilling. An extremely heavy soil like that is a good candidate for making hugelkulture beds.

I've started new beds in the housing development muck you describe many times. In time, you will see improvement. Just keep adding the organic matter. As worms show up, they will aerate the soil and deposit OM deeper for you. You can use a pitchfork to stab around under the good soil, and do a bit of lifting/rocking the handle to create some air pockets.

It's been an especially wet winter here, probably there too, but if (when) it gets "droughty" this summer, that clay base could end up being your best friend, and more water retention in the upper soil where the plants' crowns are could actually do more harm than good if it were to rain a lot. Once your plants start using the moisture and the rain slacks off, the issue will likely moderate itself.

If you find it's drying too quickly, mulching the surface with finely shredded wood or aged leaf mould can increase the intervals between watering quite a bit. When checking to see if plants are thirsty, it's always best to do that in the morning if possible. A hot afternoon can cause some plants that don't need supplemental water to appear thirsty and wilted, a common mistake especially for people who work all day, then check in the evenings.

Don't expect stellar results this year, but don't lose faith, building good soil/improving drainage takes time.

In the fall, pile as much leaves on the area as you can find, shredded with a mower or chipper if possible. In the spring, if they are still too thick, move to compost pile, but they should be well decomposed, depending on what kind of leaves they are.

In the future, instead of digging, you could use thick layers of overlapping newspaper/cardboard to put under raised beds right over grass. The paper barrier (and weight of the bed built on top of it) prevents grass from being able to grow through (and any weed seeds that may have been lurking there.) This layer will soon decompose and allow roots to roam as deeply as they want. This can be done whether using a frame for the bed, or if you just wanted to pile soil/compost/mulch atop the paper. Usually part of the "lasagna gardening" process wherever there is existing vegetation.

If you don't already, you may want to let the clippings from your lawn stay in the grass instead of bagging, which can help the lawn to be more healthy, thus also gradually improving drainage outside of the beds. You may find that actually aerating the lawn would be helpful. Substances that kill lawn pests are likely to also be poisonous to the general population of organisms that keep soil healthy (which the manufacturers of these products love because then you need fertilizer also, and a vicious cycle begins.)

If you truly want to get your soil as best as you can get it. Check this out, it's called back to Eden, there is a free video in the right of the page.. Your soil would thank you. Your back would thank this as well, I believe digging ruins soil structure...

Hope this is helpful,
Joe

Here is a link that might be useful: How to build true soil

My friend, first, thank you for following up. We all learn when someone like you 'closes the loop' and reports back from their efforts. Also, kudos for being so humble that you are willing to listen to the advice of others.

Personally, clay is the only kind of soil I would want to use. Amend it as needed, but it's the stuff that plants will grow in when it is in good shape. Being in the south, you will need to continually add organic material to your clay soil to keep it fertile. The warm weather means that the biological activity is constant year-round, so the OM gets consumed that much faster.

Congratulations for finding a working combination, and thanks again for updating us.

Good work, all around. It sounds like you are well on your way to some success. I've never been able to grow a turnip worth eating.

Great to hear that things are working out. We're always saying around here to amend the soil you have rather than try to replace it. This is a great example of the synergy between native soil and amendments.

Happy gardening and keep adding that compost. You do have a compost pile, right? :-]

You probably could add some material from used diaper/depends products. That glycerin powder becomes swelled water/pee grains, which really easy to mix in soil or compost. It will bring nutrients from pee and moist control in same time. Just open it, put absorbing material into bowl with water so it will swell evenly, then mix with your grow media.

Congrats on finding a solution!

I was going to suggest a mulch mat to lay over your soil. It would slow down the drainage, and as it decomposed would provide humus. I don't think you need it now, but it might be worth looking at anyway.

http://www.woven-earth.com

Please don't mix diaper gels in with your soils. I know there is a video floating around that makes it seem like great idea, but it really isn't. The powder is a super absorbent polymer covered with cellulose. Not only does that polymer degrade into some water soluble nastiness, it also holds on to water a little too tightly.
Hydrogels (PDF)

Interesting article about the decomposition back to acrylamide monomer, which is as she says rather toxic. One thing she left off is the biodegradability of the monomer - i.e. what happens to it when it forms in soil. It will actually further biodegrade. Although I am not in favor of using synthetics like this to improve soil (I prefer nature's methods 99% of the time), I would not be that concerned about this stuff building up in soil and creating a toxic hazard after a single or occasional use in the garden. Someone working in horticulture, though, might have an increased occupational exposure.

Environmental Chemistry of Acrylamide - Fact Sheet

Good to know

Old post but you can use the bathtub effect to your advantage by wicking water upwards. Start with clay on the bottom, followed by thin alternating layers of peat moss and vermiculite then start alternating layers of peat, vermiculite, pinebark, cow/chicken/horse manure etc. What your shooting for is neutral PH, My have to lime and would check with a soil test every other year with the peat/pinebark but that peat will pull the water off of the clay and upwards. The vermiculite will hold the water but also some air and allow the roots of your plants to uptake, and don't burry your wood as it rots away quickly. Another idea would use plastic or steel landscape edging or go with cindar block and cement it in place before people get all crazy with not using cindar blocks being toxic they may have used to be and if you stucco and paint them the leaching would be nominal granted you may want to use pine straw/bark/lime near the edges to decrease the PH and potential leaching. I am growing some hydrangias and making them blue in cinder block so I know the leaching isn't bad covering it with concrete doing it that way "if it was the would be insanely pink". Also thinking about building my cindar block raised beds with white portland, sea shell mix "oyster shell etc" and some other stuff to lower the PH so the leaching would be more beneficial than not. I always say to myself "DON"T FIGHT NATURE"... and try to use nature to fight itself.

The diapers in my experience are not bad toxicity wise but I will say I have never used more than a couple, haven't seen any risidual effects, and have never used them on edibles. I think they work better in clay pots that have a serious problem with water holding. Just read a book in which old timers used clay posts more as mini cutting greenhouses with a pot inside a pot moister wicking from outside in, interesting read from 150 years ago.

When I was in New Mexico where the humidity was very low, I used to coat terra cotta pots with varnish on the inside to retard water loss.

I do the exact opposite here in the deep south. Humidity is really high so we have a really hard time with things like rosemary, lavender "spanish", and olives. Clay pots work out perfectly with rocky/sandy soil along with composted cow/chicken manure. Also works fairly well with bougainvillea.