I want to expand my raised bed garden. Of course I'd like to build the retaining walls with something that would last well and be environmentally safe and sound. I've been reading the other threads on this over the past year, and I like the idea of Trex lumber, but the cost is high and it tends to need a lot of support with the weight of the retained earth.

We were bandying the idea of using plastic concrete foundation forms to build them up. They come with ready-made 90-degree corner joints that you just put the cut piece of foundation material into, stack it two high and drive in some rebar to keep it in place and fill.

It sounds like a feasible idea. The cost is not dirt cheap, but it would -- I hope -- last for a great many years before having to have anything done with it. Does anyone have any advice on WHY it would NOT be a good idea? What is the plastic made of? Recycled stuff? And since it is made for burying under ground, would it degrade in the UV too rapidly to make it worthwhile?

-- julie f. (rumplefrogskin@excite.com), April 14, 2001

Answers

Dirt cheap and permant? Why not use rocks and concrete. Darn near to free. Not Oil based products. Lasts for a long time. Prettier than plastic.

-- Kevin in NC (vantravlrs@aol.com), April 14, 2001.

We have forty raised beds in the vegetable garden and a hundred and one in the wifes herb garden. Have had the vegetable garden for over 15 years and the herb garden for 5. We plowed the ground thoroughly then marked out the walkways and beds. Shoveled the loose soil out of the walkways onto the beds. Took down the strings and filled the walkways with leaves, straw, wood shavings, tree bark anything we could find. Even put a layer of newspapers under the mulch when we had them. Added what compost we had to the beds and planted them. Mulched around the plants as soon as they were big enough. Kinda a combination of French intensive gardening and Ruth Stouts heavly mulched gardens. We don't use anytype of retaining walls around the beds and with the mulching with straw have had no problems. About every four years I till up the composted walk material and add it to the beds. The beds in the vegetable garden are about 15 to 18 inches above the walk ways. We no longer have a compost pile for leaves and such we just compost it in the walks and then it is right at the bed where needed. I am 60 and don't want to try to haul several thousand pounds of compost from a pile to where needed in the garden. We have found that the beds raise so much that we are converting several of them over to perennials so we can quit planting some of the beds and will have flowers to enjoy. With the raised beds the rains don't interferer with the planting like a flat garden and with the mulch they don't dry out as bad when there is little rain. Here in North Alabama we have a lot of rain but the beds don't collapse like you think they would. We never step on the beds and never have to till or dig them up. Just let the earth worms do that for you. Try it you will like it. David

-- David (bluewaterfarm@mindspring.com), April 14, 2001.

Dave, Sounds like a great idea - is your land flat or hilly? Mine is hilly and I would be afraid that the beds would wash out after some of the heavy rains. I use raised beds as I have zero good soil under the first three inches of topsoil and tilling is practically impossible with all the rocks we have. So all my beds are raised, I start with about eight to 12 inches and raise them each year. The walls are made of rocks we pick up around the farm (we have some lovely granite, flat rocks). That keeps the soil from washing out when we have heavy rains. It is a lot of work on the back though and mine isn't quite the same after years of starting young horses. I like the look of rock though and I don't use concrete or mortar to hold them, just keep the bottom a bit wider than the top line. I use some (please don't bash me!)landscape timbers around the permanent flower beds, but none around the veggies. It is not a perfect system yet, but one that we hope to keep cultivating until all beds are 16 to 18 inches high. We don't walk on our raised beds either and I use sawdust between the rows with newspaper underneath. I have been using black plastic for weed control but hate the look and am thinking of going back to just newspapers with either sawdust or wood chips on top. Other than the landscape timbers, what do you think I could do to improve? Thanks

-- Cindy (colawson@mindspring.com), April 15, 2001.

Other years I have built my beds up, using old lumber, concrete blocks, saplings cut in short lengths and held up with stakes, even had a lot of that metal wire shelving given to me out of a burned house, and that worked well when I lined the inside with Spanish moss so the dirt didn't fall through. But our soil is very sandy, and dries out too quickly. Compost dries out even faster, just kind of disappears in the hot sun and humidity. Mulching helps.

But this year, after two years of very little rainfall, instead of raising beds, I dug troughs in the dirt, shoveled my compost into the trough, and set out my plants, then packed pine needles, leaves, or hay, whatever I had, around the plants. When I water, I pour it right around the plants. Every so often I add another layer of hay. It seems to be working. My strawberries have done very well. Cabbage and tomatoes, eggplant and squash seem to love it.

Also, instead of burying my potatoes, this time I just scooped out a spot, and sat the chunk of potatoe in it, and then covered the whole beds with thick hay. The potatoes came up through the hay, and I keep adding more hay. Just a short watering session about every three days, and the hay underneath stays damp. The plants don't even wilt in the sun. And it is already in the low 90's here almost every afternoon. There is no way I could ever water the ground enough to support the potatoes my former way. Of course, this is my first attempt at this method, so I will let you know if I get any potatoes.

I have finally learned one thing about gardening in Central Florida: There is no one certain right way, not even two years in a row. I have to be ready to change methods according to the rainfall.

-- Lela R. Picking (stllwtrs55@aol.com), April 15, 2001.

My husband's company sells trex (he's in recieving, so won't mind my forwarding his opinions here... Don't bother. Its supposed to be this great wonderful lumber substitute... HA!! According to Rich, even when used on a deck (its 'intended' purpose), you have to use lumber framing and the same supports, for all that extra money. I asked him if he'd use it to build my planter, as he gets a nice discount, and he wouldn't even consider it. It doesn't last like they say, and it is made using all sorts of chemicals. Most of which you knew... I know...

Is there any reason you aren't planting the sides??? It increases the plantable area by over half. If you plant on center instead of in rows, it can increase the yield unbelievably, also reducing water use and mulching.

What about good old=fashioned rock? Large ones (still within lifting ability, of course!) would hold without needing any mortar, they are free, and they are not going to add any unnecessary chemicals to the soil. Plus, they will retain heat and they last forever.

I don't think that the plastic in the forms would hurt the garden, but I am not up on those things.

-- Sue Diederich (willow666@rocketmail.com), April 16, 2001.

I'm thinking of hay or straw bales for the new garden here. Dig out a little for the bed and set the bales in around 'em. Turn the bales under for compost in a year and get some more. That and 15 or 20 dumptruck loads of stall cleanings may begin to get this nasty used up clay of mine back to where it oughta be.

-- John in S. IN (jsmengel@hotmail.com), April 17, 2001.

i have read a book,titled, lasagna gardening by patricia lanza, it had some good ideas i plan to put into action.plus it has tips on vegetables and flowers also.it is a good book to have in anypersonal library.

-- Valory Leonard (valoryvaleo@aol.com), April 20, 2001.