Your plan is to build boxes, 24" high, 2' wide and 12' long?

You have 2X12" in your post! :)

What is the problem with your native soil? The challenge in gardening has always been to take any soil and make it productive.

Sorry, I didn't want to bore anyone with all the reasons my native soil is not workable. But essentially, it's heavily compacted hardpan clay soil full of construction debris from excavating an addition last year. And the man who owned this property for 30 years before us was a jeweler who did all his projects on site... and I suspect he used the area where i am now growing as a sort of dump area. We cleared the area of old cactus and hedges it had a bunch of stuff "tossed" into the hedges, and I just don't want to take the chance he may have dumped some of his jewelry making waste (i dunno, metals, cleaning chemicals, etc) into the site. I just don't want to deal with the local soil... and I have a really great option of a mixed organic garden soil from a professional landscaping and soil company for about $35 a cubic yard in bulk. I can live with buying a few cubic yards of that stuff and amending it every year.

My main question is whether or not the 24" deep boxes would be overkill. Or structurally unsound. Or perhaps problematic in some way other than the initial set up cost, which I can live with.

Just in the process of thinking this through, I may just do 20" tall boxes, or even 16" boxes would be sufficient for my needs.

The boxes would 4' wide and 8' long.

Thanks!
-kmama

I built a 300 sf raised bed out of Allan Block on the south side of our house, the property slopes from front to back and the front depth is 14 in, the very back is 32 in; I have 100 sf at 32 in and 200 sf at ~18-14 in. It is a strong architectural statement as well as a huge heat sink. We can spend the money on these things, and there is zero problem with this bed, and I have a cold frame on it that produces all year. In Denver.

So, if you want to spend the money, there are definitely benefits to deep beds. But the weight is something you need to consider and your posts should be no more than 4 ft on center, preferably 3 if you can afford it. You don't say the l x w of your beds, but the cubic yards add up real quick. E.g a 4 x 8 bed at 2 ft deep is ~2.5 cy. That's $100 with delivery, easy. And this is manufactured soil, so some minerals will be missing and you'll likely need to add P and K. For something that size you'll need a box of greensand and your preferred P, which is 25.00 there. And you'll want blood meal or something mid-season. Just for the soil. Just a thought. If you can afford it, you won't be sorry.

Dan

kmama-

I had the same problem. Nwe construction, no topsoil, hard packed clay and God knows what else! I have 5 raised beds that are 16" deep, and one that is 24". The biggest problem I have with the deeper one ( actually with all of them) is settling. My soil is usually close to the top in the beginning of the planting season - March ( I can garden all year round). By Mid summer, I find that depending on the plant, I have exposed roots if I don't mulch deeply. It hasn't really been a problem, and I do add compost and mulch regularly. Just labor intensive at certain times. But the plants are healthy, productive, and I tend to have them closer together than normal. The roots have enough space to go down, which in drought times, makes this system work well for me.

Good Luck!
Kathy

g'day kmama,

yes raised beds and leave the natural soil and its structure as is, you mentioned gophers for one about the only way i can even imagine keeping them out of the beds is to use sides they can't climb up (can they clinb some?)( and then you would need to lay a sheet of mesh preferrably stainless steel under the bed and up the sides a bit so they can't tunnel in from underneath (they do tunnel don't they?).

you can make them as deep as you wish or can afford to fill. but generally most go to around 2' high 3-4' wide and generally 20'(6meters) long.

there are probably many things you can use, but one thing that might be more affordable (ok it won't look garden prize pretty but it will be functional), that is galvanised corrugated roofing, you make it your self using galvanised fencing star pickets or maybe talk to a rainwater tank manufacturer (we have people here who make and sell them, maybe you do to dunno?) and see if they would pre-fab bed frames in similar dimentions as above they may only be able to go 5' long?

so far i have not been able to google up a link so you can see what i am talking about but maybe you can?

len

Here is a link that might be useful: lens garden page

Hi everyone,
Thank you all for your feedback and ideas. The more I talk to gardeners, I learn there's no consensus on any one approach and I just need to get out there and start doing. I decided to make them 16" high (2 rows of 2x8's), and dig down with a rich amendment about 12" below ground. The deep growing things like tomatoes, they can grow down if the want or need to.

And I suppose if we want to make them deeper I can always add another row of 2x8s next year.

Thanks!
-k

My hubby and I built two long raised beds out front. Sure, they are only 12 " deep, but 12 ft wide and 2 ft long. We used landscape timbers, and filled with top soil (of course amended properly). It was actually relatively cheap, because we had Lowes deliver 2 pallets of soil, the mulch, and the timbers all at once so we only paid for one shipping charge. We have done this with our beds for years, and it has worked wonderfully! If you consider that each bag of top soil was less than $2, mulch is cheap (although you won't need mulch for veggies), bags of composted manure are about $2 to $3, and the timbers are about $3 a piece. We spent probably about $200 bucks to build the two beds I have. Not bad! And you can add whatever amendments you want. And think of it this way too, you won't have to bend down as much to work on the bed, and can sit on the side a little bit too! lol

kentstar