15

Looking for advice on building a raised garden bed for vegetable gardening. Will be building two beds. Was planning for 1' deep beds, using either 2"x12" or 2"x6" (2 stacked) boards, but is that depth necessary?

Also looking for advice on best types of wood to use. Have been told to avoid treated wood, because the chemicals can seep into beds/plants. Cedar and redwood have been suggested.

All in all, trying to keep costs relatively low, as this is primarily meant to be a fun little hobby and a way to eat a bit healthier. Any advice/resources greatly appreciated.

migrated from diy.stackexchange.com Mar 27 '12 at 14:40

This question came from our site for contractors and serious DIYers.

  • 2
    Check this out, Gardening by the Foot. I've never done this but from what I understand its a pretty good do it yourself project that is pretty easy. This site has videos and lost of how to's on it help. – lqlarry Mar 27 '12 at 0:59
  • How high to raise a bed will depend also on what part of the country you are in. Where I grew up in Ohio, they were not necessary. In Texas it is a very different story, and varies across the state. Your local ag extension center may be able to offer some guidelines. I took a class through my local Arboretum. – user2020 Mar 15 '13 at 2:12
8

The raised bed is for convenience more than anything, so as for how high to make it, it's really up to you. The higher it is, the less you need to bend over. But also the more materials and effort that will go into building it.

You definitely want to avoid any sort of treated lumber, or creosote railroad ties or the like. Cedar would be a good bet.

There's lots of plans out there if you google. Here's one:

http://www.sunset.com/garden/perfect-raised-bed-00400000039550/

7

We went with galvanized water troughs. Mostly 2' tall. Easy to sit on the edge and don't have to bend as far. No digging holes for corner/side supports for the wood boxes that the dirt can bow out.

We designed the garden like this.

  • Layer of hardware cloth 1/2"x1/2" (We have lots of gophers)
  • A layer of gravel (3-4") for pathways, etc.
  • Bought several size water troughs, (You can get ones that leak at a discount!) some are 1'Hx2'Wx4'L ($70) 2'Hx3'Wx8'L ($220) 2'Hx6'Diameter ($220)
  • Drilled several holes in the bottom of the trough for drainage.
  • Placed another 3-4" of drain rock in the bottom of the trough.
  • Covered rock with TrenchWrap/landscape fabric
  • Filled to top with Organic Veggie Potting Soil.

For watering we trenched in 3/4" water pipes to each location and cut out a hole in the trough for the water line. All the water lines are controlled by sprinkler valves. 6 Valves for 15 Planters.

We went with the hardware cloth over everything so the gophers won't come up through the pathways. The gravel under AND in the troughs was to help with drainage of the water. The less standing water on the bottom of the troughs the longer the galvanized metal will last.

Here are some pictures.

Hardware Fabric and Gravel

Mostly done, 4 more 8' units to go

  • Neat project. I especially like the evidence of little helpers -- the "heavy equipment" in the top photo... – bstpierre Mar 30 '12 at 2:38
  • Oh yes, There were two, a 3 and 7 year old. They really got into it. Instead of filling wheel barrow he filled his dump truck and moved rock and dirt... We'd be done if it was not for the rain. We need it though... – scooter133 Mar 30 '12 at 14:14
5

Cedar would be the best, but it's expensive, and you may have a hard time finding it at your local big box store. Arsenic is no longer used for PT lumber, so at least from the few sources I've found PT wood appears to be safe for raised garden beds. You certainly don't want untreated wood since it will rot in no time.

For assembling, I'd used coated deck screws. Nails will pull out, and anything other than a hot dipped galvanized nail would react with the PT chemicals and corrode. The other advantage of screws is that you can remove them to disassemble the box in the future, especially if you need to replace one or more boards.

The deeper you build it, the more soil you need to fill it with, but the less you bend over. Make sure when sizing it that you don't make it so large that you can't reach part of the bed without stepping in it.

  • 4
    Note that that article is referring to CCA lumber, not the newer ACQ. ACQ is also highly corrosive to steel, so while hot dipped fasteners is a good start, you may want to go for the 'ACQ approved' which tends to be a bit more heavy duty. – DA. Mar 27 '12 at 3:56
  • @DA01 thanks for the details. Time to go read the info on all my screws now. – BMitch Mar 27 '12 at 11:24
4

As DAO1 has stated avoid any chemically treated wood.Two twelve inche boards will be fine,the deeper the soil the less it will dry out in the sun.Also be careful of the source of your soil.Many municipalities offer free compost from their yardwaste composting centers.Avoid it for anything you will consume.Many times it contains street sweepings,lawn fertilizer and pesticides.Use soil from a known source,mixed with composted manure.Prior to it being regulated painters would scrape the exterior siding and let the chips fall on the ground,the lead would be absorbed by the soil.If your home was built before 1978 don't place it to close to the house as there is a chance of lead contamination in the soil.

4

I used 2x6 pine - it was cheap. They lasted a number of years before I removed them because I wanted to change the orientation - I went back to just a flat garden.

For me rebuilding every 5 years or so is not a problem - So I went with the cheaper wood.

6" height is more than enough - I would say 12" is overkill. But it is not bad - if you have the time, money and extra soil go for the deep one, but I'd just go with 6".

I would stay away from treated lumber. I think test show that stuff leaches into the soil but I have not study yet that confirmed that it entered the food. (It seems to make sense to me that it could - so to be safe I just avoid all PT stuff anywhere near my garden)

  • +1 for the point about the arsenic treatment leeching into soil. – Lisa Mar 29 '12 at 23:48
1

See my answer to a similar question for an alternative to building any kind of structure. Unless you have really awful soil and you're unwilling to invest some time in improving it, building enclosed beds is mostly just a matter of style.

To answer your question about the depth, 1' deep isn't strictly necessary, but the deeper you have loose soil for plants to grow into, the better your results will be (generally speaking).

As a middle ground between building 1' high edges and having no edges and just gardening in the ground, you could loosen the soil about 8" (about the depth of a garden fork), work in an inch or two of compost, and build your beds with 2x6s above that.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy