Building an air prune bed

I’m exited to give this plant raising protocol a try. I’m looking forward to follow up and learn how to turn the dormant plants into bareroots and heel them for the winter, but let’s not get ahead of ourselves here…

I’m going to make 2’ by 3’ boxes. the total height will be 10.5" tall, 9" top to mesh, about 8" soil depth. The question that I have is; how much air gap should I build in? If it is say, one inch, is there a chance that the root will try to jump such gap?


If it was very very high humidity like maybe a greenhouse I would encourage more than an inch

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I’m wondering if there has been a systematic look at the ideal air gap amount. A lot of the info out there seem to be folks repeating one another.

Heck I’m going to build two, one out of cedar, one out of plain pine. I want to see how the pine one fares over time compared to the more water resistant cedar.

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What are you planning to grow in them?
This would be a factor on how deep to build. I’ve used mine for Persimmon and Pecans so far, Pawpaws next.
I started out with a couple 2x2.5’ ,2 2x6’s stacked for 11” depth. I built the next generation a 2x4 higher.
Between it sinking and debris, grass, leaves etc. I don’t think an inch will cut it for the air gap.
Here is my first attempt, after a few years of use.

Repurposed old wagon for wood. The boards sticking up were for a chicken wire fence to keep squirrels out of the Pecans. Little buggers swiping nuts as I built the fence.

Latest prototype, 30”x56”x16” tall wood. Got the metal rack on Marketplace added some supports and tabs to hold the hardware cloth up and the wood in. Hoping to get some soil in it this weekend.

Looking forward to seeing yours!


I really like your original design; very practical and elegant based on the dimensions of the materials at hand.

I have a few nice pieces of 3/4" thick and fairly wide pieces on both cedar and pine. I also have 2x4 in cedar and pine. I’m going to build a box each of those materials; as a side experiment I want to see how well pine holds compared to cedar. Hopefully I’ll be able to post a few photos by Sunday.

How is water retention on these? I guess it depends on the soil but do you find that they dry out fast? I don’t use perlite a lot but it with these it seems that a healthy amount of it should help.

Mark I is going to be 10 1/2" tall based on the width of three 2x4 pieces, actual inside working depth will be around 9 1/2". As stated this is Mark I; I’m looking forward to learn on these and that alone is a win. I’m sure even if I have need for something deeper that these would serve well for some plants, or even seeds.

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This is one I built for rootstocks. I planted last year and I am just getting ready to graft. 2x12s for depth and straw bales over winter to keep from root damage when below 0. Top to keep squirrels and birds off the grafts.


Very nice!
My gen 1’s didn’t have enough support on the outside edge of the hardware cloth. Seems like your design covers that. That much dirt gets heavy.
Looks like your rootstocks did really well.
@don1357 Holds moisture pretty well. The outside dries out the fastest and plants too close can suffer the consequences. I’ve been using native soil with Peat mixed in to lighten it up a little.

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Yes, that is a lot or weight in dirt. You could move it with a skid loader and pallet forks, but there isn’t no moving it around other than that. Graft this year and next spring take off two side boards on one side and start separating them out to transplant. I’m anxious to see what those roots look like.

I built my Mark I boxes, these are 12" x 30" inside dimensions. I’m thinking that eventually I’ll standardize to 18" by 24", based on where I want them, ability to move them, and to double duty them as cold frames.

At first I wanted to use the 6" mesh but what they had at the hardware store was garbage; ridiculously thin and rusted enough to be structurally unsound. I walked around until I found something I could use, which was fiberglass rods you stick on the ground. The actual mesh just rest on the bottom so I can change it if I don’t like how it is working.

I also built one out of cedar, another with plain white pine.i want to see how much a difference it makes.


I put some hay at the bottom to help hold the mix, about 30% loamy screened soil, 50% well cured horse compost, 20% perlite. It soaks water and drains like a champ. I then proceeded to load 50 Willow cuttings and about 15 second-tier haskap cuttings, the ones with sub standard root development that were not potted earlier. They can swim or sink there.

I picked Willow because even with sub standard effort I should get a high survival rate. I want to see what sort of growth I get in one season, both for top and root development. Part two of the experiment is to pull them all once they go dormant and to heel then as a bundle for potting next spring.

While I have some haskaps there I don’t think that they are well suited for an air prune setup, their root system is more shallow and mat-like. Then again I’ll get a chance to see what they do.


I made some small 1x2 air prune boxes last year and fall sowed a bunch of various seed I had. I then covered the tops with hardware cloth to keep the rodents out and buried them in a wood chip pile for the winter. This spring I have seen some decent germination.

I like the small size so that I can easily carry them around, they also stack up neatly. I’ll prop them up on rocks and/or bricks to get the air gap.



Nemaguard peach

American plum




That looks nice!

We have a super short season here, I want to do a small scale backyard nursing, and I’m trying to develop techniques, equipment, and a workflow that will work with those parameters. The plan is to have a variety of suitable trees doing a first year on these boxes, then pulling them out and bunching them so they can be heeled for the winter. The boxes are then loaded again with the next year’s batch. Once the next spring comes both boxes and bareroots (to be potted) are brought into the greenhouse for an early start.