building new planter boxes

[mr_yan]

I just obtained some 1x6 redwood which is real 4 quarter thick which I would like to build some new veg planter boxes out of for my patio.

14 or 16 inches wide is all I can go and about 3 feet long will be the most efficient use of the wood based on the lengths.

Any thoughts on planter depth. My thoughts are 15 deep - rip off 1.5 inches from the top and bottom horizontal pieces for use these as trim frame.

 

[RonsGarden]

15"s might be a bit short....
I'd go at least 18"s deep.

 

[Markymark]

I would say 18 inches is important for vegetables like carrots. But most root-balls are near the topsoil and is only around 6 inches below the surface. So I don't see why 15 inches would hurt anything. Now don't ask me about flowers and those types of plants because I don't really grow them due to edibility (of course many are).

 

[millert25]

Being that you are referring to veggies I second that opinion to go at least 18 inches, maybe 16 at the very least.

 

[drivepirate]

My first boxes were only 8" deep. I followed the square foot gardening book and used good rich soil. The first year was great. Tomatoes, lettuce, green beans all did awesome. The second year wasn't as good. I think if you keep it watered that 15" will be fine.

 

[Randy]

I know you didn't ask about this, but I bought some pressure treated lumber a few weeks ago to redo the deck in my utility trailer. I have seen posted several times that you shouldn't use pressure treated lumber for raised beds. But there was a tag on the lumber that was contrary to that and it said the lumber was okay to use for gardening purposes. In the past, pressure treated lumber was treated with an arsenic compound and that would not be okay for gardening, but they quit using that compound and you won't even find it available any more. I believe there is a certain amount of arsenic in the soil anyway, but there is no way for the average person to tell if and how much there is.

 

[mr_yan]

Modern treated lumber uses ACQ - Alkaline copper quaternary. Really it is just a compound of copper and ammonium. As I understand it plants in general don't like copper and the insects don't like the ammonium and fungi don't like either. The data I've seen on lumber treating chemicals leaching out into the surrounding soil and also entering the plant has been inconclusive at best. Most people who say you shouldn't use treated because of chemicals aren't able to site a reason beyond it has "chemical" in the name.

Treated lumber will still break down though. From everything I have read standard lumber lasts 4 to 6 years if using 2x stock while treated will get you 6 to 8 years for about twice the cost and cedar will get you 8 to 10 years for a stupid level of cost. As I see it buying anything beyond standard lumber is just a false economy savings. This is the reason I use regular dimensional lumber.

I'm making this out of 4/4 redwood that my neighbor had as scrap and was trashing and will be using 2x stock for the structural members to attach to and random ply for the bottom.