Hello Katie
I have a few questions for you and maybe you could help me, i have built a 4'x12' raised 3 feet off the ground garden bed and have drilled holes in the bottom for drainage.
I am gong to paint the inside with non corrosive oil paint to try to preserve the wood and paint the outside with exterior latex paint for the look is this a good idea, then i will put geotextile at the bottom of the bed with old wooden tree trunks, then cover this with grass and plant residue from last years growth ,and in this residue there is some little cedar mulch, the question here is the cedar mulch bad for the plants that i want to plant.
After this i will put in top soil with compost ,and then cover it with sheep manure, then at the top i will be covering it with Cocoa mulch after planting the plants grown indoors .
The plants that i will be growing are tomatoes, peppers, green and yellow beans, radish, salad, cucumbers, carrots, zuccini.

Thank you in advance Robert

Hi Robert, I wonder if you'd be able to post a picture of your raised bed for us?

I'm having trouble picturing a raised bed that big but "raised 3ft. off the ground". i.e. is it a box with air underneath, or is the tallest side of the bed 3ft. tall (which makes sense to me with regard to not having to bend over).

I don't think the cedar mulch will be a problem, as long as it's finely shredded and mixed with other organic material. The only concern I'd have is starting up your bed with so much un-composted material in the bottom of the bed. While organic stuff is breaking down, it uses nitrogen out of the soil so it can 'rob' nitrogen from your plants. It also needs oxygen or it can become stinky and ferment instead of composting. Anaerobic vs. aerobic decomposition.

Yes by "residue" do you mean composted grass and plants? Is the sheep manure rotted? As Elaine says too much 'fresh' ingredients would be trouble I think.

Hello Elaine

http://garden.org/i/s/thankyou....

Thank you for your info,here are 3 photos of what i mean by raised bed garden.
i gather by what you say i will be putting to much scrap at the bottom .
So i take from what you say it is better not to put to much scrap.
At the bottom i will be painting with oil paint to protect the wood, then put geotextile all the way long the bottom and sides, then put in 24 bags of 50 litters garden soil with compost all ready mixed into the soil, then16 bags sheep manure all ready in bags of 30 litters to fill the garden what do you think.

thanks in advance
Robert

My first thought, after seeing your pictures is, it's going to be awfully heavy once you get it filled with soil, plants and start watering. I'd recommend you put in some cross-bracing to prevent the box from sagging outwards in the middle. You might also need more support underneath. Be sure you also have plenty of drainage holes - some out the sides as well as the bottom might be a good idea.

I have a 3ft. x 12ft. raised bed made of Trex that sits on the ground. When my friend built it for me, he put in X supports across at two points inside the box that are now covered with soil. They hold the sides of the box so it has not sagged outwards in 9 years of use.

Also, are you sure that composite board will hold up to the constant moisture of a vegetable bed? It might have been wiser to build it with marine plywood that is meant to be wet.

Last thought for right now, is the sheep manure thoroughly composted? It can be very high in nitrogen and salts, which can burn young transplants. Be sure you mix all your soil components thoroughly so that the manure doesn't come into too much direct contact with your young plants.

Robert, I agree with everything that Elaine said. I would never use this compressed fiber wood. The least bit of water will quickly destroy it. You could build it with marine plywood and treated lumber supports or perhaps the composite decking material that will never rot.

Perhaps you could treat the box with Cedar Shield. That might help preserve it from water. And I would think about bracing it - it will be very heavy once filled with soil. I learned a trick once, for filling large pots that you don't want to be too heavy -- place broken up pieces of styrofoam in the bottom and the soil on top of the styrofoam -- the roots will probably not grow that deep, but if they do, there will still be soil down there, in between the pieces of styrofoam. This would lighten the box considerable, and also keep the soil from compacting at the bottom. I have had very good luck doing this. Keep us posted!

I agree, Styrofoam chunks are useful when used to lighten large, soil-filled pots.

I have no suggestions for the raised beds but one thing I have learned is to keep Cocoa mulch away from dogs.
Good luck with the project; it sure looks beautiful.

greene said:I have no suggestions for the raised beds but one thing I have learned is to keep Cocoa mulch away from dogs.
Good luck with the project; it sure looks beautiful.

Thank you but why keep cocoa mulch away from dogs

If you use the key words "cocoa mulch theobromine dogs" you will find several answers. Chocolate/cocoa is bad for dogs even as mulch. (Who knew? )