Building a raised bed in the South

Hi all! It's nice to be here.

I am currently preparing a raised bed for next year. I live in the northern Atlanta Metro area, and have lots of red clay soil. Now, I know that this soil needs to be amended with compost and whatnot, and have since started a compost heap which is coming along nicely, and should be ready by next spring. I am looking to grow corn, bush beans, and tomatoes next year. This plot is not very big (12x4 ft) but even though I have 1/2 acre at my disposal, I'm trying to start smallish. This area will also get full sun as I have few trees on my property. However, I'm worried about drainage. I've never done something like this, so here is my question- should I put gravel or something down for drainage, and then cover it with soil? The wood boards I'm using are 6 inches deep.

Does anyone have any suggestions or comments? I have the frame built, but I'm not sure what to do at this point.

Thanks so much!

Check out

http://www.squarefootgardening.com/

Thanks for the link!

Hi Gryfonclaw,

I am doing the same thing. Building the boxes now to try for the fall season, haven't done well at all with a regular garden in the summer.

I have been trying out Mel Bartholomew’s Square Foot Garden Mix, in smaller containers, to see if I want to use it in my 8X4 garden boxes, but having some problems with it. Not only the peat moss is very hard to get wet, it does not absorb the water it just sits there, but if I try to wet it prior to putting it in pots it sometimes clumps, so I am left with this big clumps of medium. Right now I am not sure if the 1/3 peat moss, 1/3 vermiculite, 1/3 compost that Mel suggests, would work for me. Also have been reading Peat Moss is highly acidic. I am just so confused, it seems the more I read the more difficult to make decisions.

Anyway, thanks for asking this question, I would love to find out some tips regarding in how to use peat moss correctly, or what would be a good mix to use in raised container vegetable gardening, I live in the south as well, Florida to be exact.

Great question :-)

I've adjusted the Sq. Ft. Gardening to fit my area.

I have a clay mix soil that sucks. So, I used a composted soil mix from my local landscape center. Had 3 yards delivered to fill our beds.

I added soil conditioner to the clay and tilled in the original ground beneath the beds. I then mixed in fertilizer in my mulched soil and filled my beds with the soil. Some areas I added sand to the soil mix, some I added vermiculite. Depends on what I planed to plant in that area. The permanent bed of strawberries and asparagus got sand and vermiculite both to make it drain well.

I would avoid using rocks/stone/pebble or anything as a base for drainage, especially if you plan on growing any root vegetables.

Here's a link to how we built our beds: http://davesgarden.com/community/forums/t/983993/

What is a soil conditioner? What exactly is the function of Vermiculite? I thought it was to keep the soil moist, but so is the peat, right?

Qinx, you didn't use any peat?

Hi Aunt Busy!

Peat Moss is a mystery to me as well, I'm not sure how to use it really. Hopefully someone here can enlighten us on its appropriate use. My topsoil here is totally clay, a bright red and seems to be way too much work to condition without just using a raised bed.



PS- Is Floridian soil kind of sandy more so than clayey? Just curious.


Qinx, thanks for the sand and vermiculite suggestion. Would the addition of sand help the clay soil I have? Thanks.

Qinx, that was a fantastic thread and images on your garden beds! That will be very helpful to me. I should consider more permanent bed structure like you have. Very nice.

I did use Peat in my mixture also. Poured the dirt, peat moss, fertilizer, etc. and mixed it all with a hard steel rake as I filled the beds.

Vermiculite makes the soil lighter and friable. Doesn't clump together. Allows for good drainage but the mine extracted vermiculite is rough and jagged and holds moisture. http://en.wikipedia.org/wiki/Vermiculite

The soil conditioner I used is called Clay Cutter. Our local nursery carries it in 2cu.ft. bags. I'm not quite sure what is in it. Looks like compost, dirt, etc. Very organic. It mixed well with the clay when I tilled it. http://en.wikipedia.org/wiki/Soil_conditioner (Compost, Leaf Mold, Manure, Humus, etc.)

Contact your local agriculture extension and ask them how to amend your soil. I'm sure there are a few around here that have the same soil conditions you have that could make a recommendation. The soil here in VA while it is clay and sand, isn't the same hard red clay found down there! So I'm sure a different mix may be better for you than what I used.

If you do go with a totally raised bed, make sure it's deep enough so you don't have to worry about the ground soil. My retaining blocks are only 6" high, so I tilled the soil under the beds another 6-8 inches with the soil amendments.

Farmerdill, what say ye? You're from GA!

Hi Gryfonclaw :-)

Yes, our soil is very sandy. The raised beds were just to avoid, pests, diseases, weeds, or whatnots that might already be in the soil.

The Square Foot Garden Book, makes it sound like it is so much easier to garden with their special mix. If you make your own soil part of the mix....the whole purpose is defeated. In the other hand, I made some of Mel's mix, to try in some big pots, and having some trouble with the peat.

Besides the pots, we also planted an area of my yard, where we just ripped out the grass, added some garden mix, planted sunflowers in that patch and they are huge! At least 10 feet tall, they have done great. That area of my garden has done the best, but also sunflowers are a tough sort of crop.....

I, like you, just don't know what I should do, if I should put my faith in Mel's mix and try it anyway, or make my own incorporating some of the local soil.

BTW in Mel's book they tell you to cover the bottom of your raised bed with landscape cloth, then add your mix, that way you don't have to worry about weeds, nematodes. etc. They also tell you 6 inches is enough height to grow most crops, unless you are growing root veggies in which case you must make a higher box.

Interestingly, I looked on my county extension site and all it seems to say is "add organic matter". Some local gardening forums warn against sand in particular. Good to know. I'll look more into vermiculite.

Playground sand, usually what you find at the big box store, is bad because it's so fine. Course sand is better. I only used sand to mix in with my Asparagus

Asparagus is so awesome. It seems so hard to manage...Do you need a cool climate to grow it?
I would die happy if I could pull that off.

It grows almost everywhere. Does not like to stay wet though.

http://www.settfest.com/2009/01/a-crash-course-in-se-texas-tomatoes/

lasagna gardening anyone? I thought it was silly until I tried it this year. I just tossed some newspaper on top the grass/dandelion/misc weeds and layered stuff on top of it. I mostly used what I had on hand...aged horse manure, old hay, dry cottonwood (aka poplar) leaves, a little coconut coir, and a little potting soil. Everything in it is doing well except some watermelon but I don't think the bed is the issue. Normally you'd make the bed in the fall and let it sit/decompose until spring but I got a wild hair to try it and planted in it literally 10 minutes after I finished piling everything up. It ain't pretty but it's working. I'll take healthy plants in an ugly bed any day.

Also, under the weeds, newspaper, etc. my soil is pretty much clay. Slippery when wet and like concrete when dry.

Thanks for the tip, Dorkasaurus. I just need to finish off adding some metal braces to my frames, and I'll be good to go- you know, I'm wondering if I should just start adding my composting stuff straight up to the bed...

well try typing "lasagna gardening" in your favorite search engine for more precise methods but if i remember correctly the idea is alternating layers of "brown" and "green" stuff and keeping them moist through the winter to aid the decomposing process. The initial layer of newspaper or cardboard is supposed to suppress weeds and attract earthworms, which will help loosen the native soil underneath the bed. It pretty much is a compost pile. Mine has already dropped a few inches in only two months and when I dug down in it to the (what used to be) grass I found a lot of earthworms, plus the grass and weeds it killed also turn into food for my garden.

I have two 40x5 feet raised beds and a 24x5 foot bed. I love this type of gardening. Once the beds are build and in place the work is a lot easier than traditional gardening. To me, one purpose of raised beds is to get away from the sorry soil that you might have. Mine, in the only area I have big enough for gardening, is what we in Louisiana call white crawfish dirt. I dig it as deep as I can and rake grass roots and through them out. Read in one post about layering newpaper in the bottom, black and white only, and this sounds good to me. Put in compost, cow manure compost from wall mart is good, or look locally for a good compost, if you can find rotten hay to add this is good and helps hold moisture. I've only used peat moss when I filled my bed with top soil. Used it to loosen up the soil. By the way, the top soil I used wasn't the kind you buy in a bag. If you can find rabbit, quail, or chicken manure you can add this, also. Just not very much. I use a five gallon bucket full on eight feet. If you are just using compost to fill your bed, I would forget the peat moss. You won't have to worry about drainage in a raised bed. The excess water will come out the bottom. Raised beds are like potted flowers, they dry out easily, so keep watered. In the high temp we are having in Louisiana, I water mine every other day. Six to eight inchs is a good height for the beds. A hint is to cage every thing you can. Make it grow upward. I cage tomatos, squash and cucumbers. Found out from experience this year that I need to put small cages around peppers and egg plants. You will enjoy raised bed gardening, the good veggies and the pleasure of sharing with your friends. I keep my sister, my wife's sister, several widows and some friends in fresh produce. This year I've had running string beans, bunch butter beans (lima), lettuce, radishs, jalepeno peppers, bell peppers, beets, cabbage and a lot of tomatos. Use your imagination and utilize your space and you will be amazed at how much you can raise. P.S. I'm going to some type of drip irrigation next year.

Jim41 - your set-up seems close to mine. I have five 24' x 4' raised beds 6" deep filled with anything organic I could lay hands on. I am planning to put in a drip irrigation system for next year, but with so many options, I don't know where to start - any suggestions?

I've already put down coir and compost for a sixth bed - it hasn't rained here for a couple of weeks, which is slowing down the production of new soil from all the leaves I have scattered about. My two Biostacks are full of grass/leaves and the contents are really hot! Hopefully the weather will be cool enough during the mornings this weekend that I can turn the contents, it's just too hot to be in the garden in the afternoons.

I haven't made up my mind yet. Just looked at Wal Mart a little while the other night. I'm going to make a trip to Lowe's and see what they have. I kind of like the quarter inch tubes and mist valves for my string beans, squash, and bunch bean bed. Think I will probabaly use drip for tomatoes and cucumbers. I would like to find 1 gal. or 2 gal. per hour instead of the 4 gal. per hour Wal Mart has. My 5x24 bed is what I plant cantalopes in and have no idea what will be best in them. Might try a mist type. All I have in my beds are Gin Trash. Got a friend to haul me a big dump truck load last year. Made a probe out of PVC pipe and drilled tiny holes in it. Plugged one end and put a hose fitting on the other. I would work that thing down through the trash and run water. It is just like coffee grounds this year. It just drys out to fast. Bought one of those little Midas tillers to plow up the beds with. That old shovel got tiresome quick. I was thinking about adding some perlite to mine this fall when I plow them up. Works good in flower pots to retain moisture. What do you think? Send me your email and I will send you an invitation to look at my beds on Kodak Share.