raised bed garden?

[anthonyk]

Another question for any of you serious farmers or gardeners:

My land is mostly clay. By that I mean real clay. 4 inches of topsoil, then 30 feet of that grey thick clay that if it gets wet, sticks to you like road tar.
I've dug down about 25 feet with the backhoe doing the pond, and never broke out of it.

So my problem is that it's hard to plant anything.
I'd like a small garden next spring, maybe 20x20 and I was wondering if a raised bed would be the way to go.

If so, how high should I make it? I was picturing a box frame made of 2x12's and filling that with load of good dirt or topsoil. Then fencing the whole thing.

Any tips, suggestions or ideas would really be appreciated.

Anthony

 

[ToadHill]

If you want raised beds, think of how deep the roots of the plants you plan to grow will penetrate. Carrot and potato's will need deeper soil than beets or melons.
That said, 2x12 should be more than enough. If you are going to fill the beds with purchased soil have a soil sample done before you purchase it. I'd suggest mixing compost with the soil, along with a little sand. It's easier to amend the soil before it gets into the bed.
Consider making several beds 4' x 24' with a walkway between them, that way you can weed the beds without compacting the soil.

Have fun in the garden!

 

[anthonyk]

thanks, that 4x24 idea never crossed my mind.
that's a good point

anthony

 

[ScottOkla]

Landscape timbers have been on sale at the big home improvement centers this summer for about $2.00 per piece. I bought 105 of them and just finished constructing 7 raised beds that are 4' wide by 16' long by about 9" deep. (each timber is about 8'x5"x3", so 15 were used for each of my beds.)

I spaced mine about 2.5' apart, parallel to each other. My good soil was about 4" deep, so I was able to use the soil from between the beds to add inside the beds to bring the levels up to nearer the top of the beds. Compost and sand will make up the rest the soil in the beds.

In between the beds, I am using some scattered 12" square pavers that I got very cheaply at an auction, with sand spread around the pavers and landscape fabric beneath.


It all sounded like a good idea when I started, but between the cost of all materials and the time needed to level the ground and the timbers, it became expensive. I spent most of my free time in August working on it. Looks great so far though, and it should last 8 or 10 years. My heavy soil cost me much of my garden the last two years due to excessive rains that killed the seedlings.

 

[TedLaRue]

I think ToadHill's and Scott's posts provide a pretty comprehensive reply. For emphasis I'd like to repeat the suggestion of "making several beds 4' x 24' with a walkway between them". The initial cost for the lumber is quite a bit higher, but it's worth it. It's much easier to access your plants with the walkways in between the beds, and, as ToadHill says, you don't compact the soil by tromping on the soil the plants are growing in (especially when the soil is damp after a rainy spell and you really need to pick those beans).

There's controversy about whether it's ok to use treated lumber for your boxes. Personally, I would use treated lumber, but I'd avoid growing root crops (carrots, potatoes, etc.) where they might be near the treated lumber, at least for the first year or two.

One other suggestion: Tie your 2 x 12's at the corners with straps. You can buy galvanized steel reinforcements (Simpson Strong Tie is a well known brand, but cheaper brands are available, ask for "joist hangers" at your local "home center" and you'll find the corner reinforcements nearby) or you could buy a roll of strap for hanging pipe in the plumbing department (this might be copper or at least copper plated which might look nice in your garden). Fold a piece of the strap around the outside of the corner where the 2x12's meet and nail the strap to the 2x12'. Use galvanized nails (preferably the galvanized joist-hanger nails). All of this hardware should be available at your local builder's store or big box (Lowe's or Home Depot, etc.).

For a reference, to fill a 4' x 24' bed 11" deep would require about 3-1/4 cubic yards of topsoil. A single 20' x 20' bed 11" deep would require 13.6 cubic yards.


Totally off topic, but... Never burn treated lumber!! The smoke can cause serious breathing problems. I've personally seen this happen to an individual.

 

[VABlue]

Another option is railroad ties. Several of my nieghbors have built beds out of them. I can get them for around $7-8 each here, but have no idea what your cost might be.

 

[dmccarty]

The other alternative is to use retaining wall blocks. Its more expensive but it won't rot.

Later,
Dan

 

[charlz]

You could dig some of the clay out where the beds are going to go to get soil more depth. Say down 12" with a hole and up 12" with boards and you have 2feet of soil for root crops. This can save you some $$ on boards. Downside to this is that if that clay does not drain at all then it would turn into a bathtub under your raised beds.

Fall is coming and you could treat those empty raised beds as trench compost piles. Just start throwing all the grass, leaves etc you can in there. Being where you are it should break down nicely all winter long with some watering to keep it moist and a little turning/tilling. Come spring throw on some soil, till it in and you should be good to go.

Charles

 

[bigtiller]

thanks, that 4x24 idea never crossed my mind.
that's a good point

anthony

I like them 3 feet wide. With 4 foot wide ones the center of the bed is 2 feet away. To reach the center you have to put a foot in the bed or suport your body some how because you will be leaning out past your center of gravity.

 

[Chuck52]

I'm using concrete blocks. The holes in the blocks turn out to be useful for holding pcv pipe sections, as for a cold frame, or sections of cattle panels to support vining crops, etc. My wife wants to plant marigolds and other insect repelling flowers in the holes. The blocks last basically forever, and are cheaper than the decorative blocks. You may find used ones, but I went to a local producer and bought seconds for about 60 cents each. For a 4x24 bed you need 42 of the 8x8x16 blocks (or the 6x8x16 if they are cheaper). You could always stack them if 8" isn't deep enough, but I'd probably just amend the soil under the bed to make it as deep as I thought I'd need with one layer of blocks. My dirt is actually pretty good, so good in fact that I have lots of weed problems. I find that having a defined raised bed not only gives me the benefit of amending the soil, but also makes weeding easier when needed. As a last resort, when the weeds in a bed got away from me, I simply covered the whole bed with plastic and let the sun do the weeding for me.

Chuck