Above Ground Garden Depth?

[OldGuy43]

This seemed to be the place to ask even though it's not exactly about indoor or greenhouse. How deep does an outdoor above ground vegetable garden need to be? I'm guessing, but I think that the corn would have the deepest roots?

 

[catjac1975]

I'm guessing this is not a raised bed?

This seemed to be the place to ask even though it's not exactly about indoor or greenhouse. How deep does an outdoor above ground vegetable garden need to be? I'm guessing, but I think that the corn would have the deepest roots?

 

[OldGuy43]

No, it 's going to be a raised bed. Sorry, didn't make myself clear.

 

[catjac1975]

I would say 6 inches is enough but some of mine are 12".

 

[897tgigvib]

It does depend some on if the above ground soil is on top of a solid hardpan layer, or if there is some transitional mixing with decent soil underneath. Things like Grapes and Blackberries will push their roots through the hardest hardpan.

Beans can get by with 5 inches of rich compost. So can Amaranth. Corn will want 18 inches at least, and that would be for the shorter varieties, like the 6 footer varieties. One of my patches of little knee high Gaspe Flint Corn I tried in a shallower 10 inch bed, and it did just as well as the Gaspe in my deepest bed, close to 30 inches deep. Both My Japonica Flint were in 20 inch deep beds and did very well. Those are 6 footers, but this year grew to 8 foot.

Tomatoes prefer it deep. Mine are both doing well, slightly shaded to hide from Gophers, companion planted with the not recommended Beans, in soil somewhere over a foot deep. The Safeway Cluster is a medium sized indeterminate, and the Big Rainbow is a full sized indeterminate. Tomato roots spread pretty well in compost, and I'm pretty sure some go into the subsoil.

My subsoil is hard as diamond clay. I could use it for pottery if I knew how! Since I had to have excellent drainage, I levelled and graded it to several underground seeps I made. Channels with wood chips and organic stuff in them, some places covered with old wood, others with stones over them. These channels lead to the ravine. They are very effective slow seeps during winter rains. These, and the rest of my garden's base is covered with plastic netting to reduce gophers. Over that is a layer of old Leaves and partial burn from the burn pile. That was 1 to 4 inches deep. I'm sure it has settled by now. Over that are my raised beds, all which will be raised more this winter. Compost shrinks.

You can start with a shallow depth like 6 inches for most things if your soil is mostly rich compost, and build it deeper in following years. For the things you want to grow that want deep roots, make those beds deeper the first year.

That's the other old guy's way of doing it! Not everything all at once like a youngster!

 

[Smiles Jr.]

Yeah, it looks like we need to know if you're talking about a raised bed where the soil in the bed is directly on the earth. Sometimes when a person says "outdoor above ground vegetable garden" it could mean a garden on top of a platform or bench and the soil in the bed does not come in contact with the earth. What say ye?

If you're talking about a typical raised bed (on the ground) the depth is not nearly as important as a table-top garden. The roots in a raised bed can go as deep as they want because there is soil under the bed. Not so with a table-top garden.

I personally like to have a raised bed made of 8" to 12" tall walls. Don't ask me why as I think a 4" or 6" bed would be fine too. If you use 4" to 8" walls amend the soil under the bed prior to filling the bed. If you're going with anything taller (or deeper) than 8" soil amendment under the bed is not so important. Make sense?

 

[catjac1975]

I visited an old very well know daylily hybridizer in Florida last spring. He had his beds up on platforms. He showed me how the tree roots from very far off infiltrated his beds that were not raised up. What challenges they had to overcome!

Yeah, it looks like we need to know if you're talking about a raised bed where the soil in the bed is directly on the earth. Sometimes when a person says "outdoor above ground vegetable garden" it could mean a garden on top of a platform or bench and the soil in the bed does not come in contact with the earth. What say ye?

If you're talking about a typical raised bed (on the ground) the depth is not nearly as important as a table-top garden. The roots in a raised bed can go as deep as they want because there is soil under the bed. Not so with a table-top garden.

I personally like to have a raised bed made of 8" to 12" tall walls. Don't ask me why as I think a 4" or 6" bed would be fine too. If you use 4" to 8" walls amend the soil under the bed prior to filling the bed. If you're going with anything taller (or deeper) than 8" soil amendment under the bed is not so important. Make sense?

 

[OldGuy43]

They soil under the bed is poor since it was at one time an asphalt tennis court. The asphalt is pretty well broken up but...? I'm planning on laying cardboard down on the bottom since there are a lot of rhizome weeds growing there now.

 

[897tgigvib]

Oh. Use plenty of that cardboard, and I would go with deeper raised beds with easy working mainly compost. A foot minimum. Don't let those weeds pop up between the beds.

:weight

:mow

:tools

Try to design your beds so they will be easy to use. 5 foot wide beds are for those who enjoy yoga and stretch exercises. 3 foot wide beds are so much easier!

 

[catjac1975]

You're not leaving the asphalt are you?

They soil under the bed is poor since it was at one time an asphalt tennis court. The asphalt is pretty well broken up but...? I'm planning on laying cardboard down on the bottom since there are a lot of rhizome weeds growing there now.

http://i185.photobucket.com/albums/x91/OldGuy43/For EasyGarden/More Weeds/GroundWeeds1.jpg