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Trees in a Hoop House

Posted by Micah Helser 
Trees in a Hoop House
February 24, 2022 11:46PM

Living on the edge of 5b, some stone fruits have shown not to survive our occasionally harsh winter. About six years ago, in an effort to ensure winter survivability and to make use of the awkward inside edge of a hoop house, I planted and trellised peaches, nectarines, cherries, and apricots. Survive they did; fruit they did not. Despite their vigorous vegetative growth, the lack of early season pollinators, and even more troublesome, early blossoming, has lead me to reconsider the location of these trees. It seems just a single layer of plastic overhead is enough to break buds early, but not provide adequate thermal protection overnight. Further, expanding root growth into adjacent beds has begun to compete with my annuals. I'd happily make that concession with an armful of peaches, but that has not happened.

I'd like to share these findings so that others who may be considering this system might benefit, and to solicit advice on a way forward. I do not want to heat the hoop house, and covering the trees with row cover is not feasible. So barring any strokes of wisdom from the community, I've decided to test winter's fate and transplant the trees outdoors. So what recommendations might one make to transplant relatively mature trees by hand and possibly the assistance of a tractor loader from a tight space that is climatically one-month ahead of the new transplant site? How heavy should I prune to minimize evapotranspiration? What's the minimum amount of root I could take? When should I do this? Thanks.

P.S. I can share pictures if someone can direct me to instructions.

Saint Ignatius, MT

Edited 2 time(s). Last edit at 02/24/2022 11:49PM by Micah Helser.
Re: Trees in a Hoop House
February 25, 2022 03:42PM
Hi Micah,

I've had a hand in transplanting larger ornamental crabs (dolgo, thunderchilds, etc) that stayed too long in the nursery. I wouldn't move them until their new home is warm enough. How much root to take is always as much as you can. That will depend on machine access, stubbornness and extra hands. A shovel handle all the way around is a great goal but will be hundreds of pounds if you have good soil and lots of hair roots.

Sharpen your tree spade (ideally it's a spade that's one piece of metal. the brand we use is King of Spades. Wooden handles can break when used this way) so it will cut through roots cleanly when you slam it into the ground wearing your sturdy boots. Use the spade to cut all around the tree. When you have the root ball loose all the way around and as deep as you can get it, put two spades in on the same side of the root ball and pry it up. This is where those extra hands come in. While two or three folks are holding the spades to the ground and the root ball is tipped, you get in there with your hand pruner and clip any roots going past the edge of your ball. The goal is to lift the ball out as cleanly as possible and those extra roots have a way of making your root ball fall apart if you leave them cuz you want all the root you can get. Ask me how I know...

Okay, that side of the root ball is free, your pals have kept it up in the air the whole time. Now you slide your tree movers underneath. These can be purchased but are expensive for a one time project. What works just as well and you or one of those extra hands may have lying around is a set of tire chains. Work those in under the spades as close to the center as you can get them. Remove the spades and repeat on the opposite side of the root ball.

Now you lift the tree out of the hole using the tire chains onto an extra large piece of burlap that you prepped right next to your hole. Tie the burlap around the root ball, two corners on one side the trunk and two corners on the other side of the trunk. We sometimes reinforced with twine or arbor tape. It depends on the sturdiness of the root ball.

If I could, I would do the digging and wrapping while the trees were dormant and cover the burlap wrapped root balls with wood mulch and leave them until the permanent holes were prepped. With enough mulch that's kept damp those trees can live quite a while in the transitory home. When you go to plant them, untie the burlap but do not remove it. You will do root damage if you do. Just tuck it into the hole. The roots will grow through it and it will break down.

Oh yeah, they make a specialized root ball mover. You can mimic it with a hand truck and some boards. This is not a complicated project. All it takes is enough friends during, cider and pizza afterwards and maybe some ibuprofen tomorrow.
Re: Trees in a Hoop House
February 25, 2022 09:42PM
Micah, I have done some testing in high tunnels and my opinion is that it is certainly possible but has more to do with the interests and personality of the grower. I did experimenting with a bunch, but mostly apple and grape. You may want to look at Hope Farm in Hereford (UK), where Andy Hunt grows 30 miles of sweet cherry under tunnels. Not a typo, 30 miles. Not sure if this is a good thing or not, but clearly it can be done well. Also, Shane has a good method above for moving them, but I will add that you can tease out almost every last length of root if you are patient when transplanting. A fork is a good tool for this. It takes a good long time, and ideally an overcast day but it means less tree shock. The method is similar to an archeological dig. When you do this of course, you will need a wider (though shallow) hole for the final location. Back when I was only using hand tools I was able to take out 5 inch caliper shade trees with a pick axe and manure fork while retaining most of the root system.

Edited 1 time(s). Last edit at 02/26/2022 02:41AM by Todd Parlo.
Re: Trees in a Hoop House
February 26, 2022 01:56AM
The dynamics of hoop trees involves allowing enough chill hours so the trees break dormancy with fruiting intentions. The most extensive fruit planting under plastic I've been in was in New Mexico, seems like a couple acres' worth, this when visiting different farms in the Southwest with Gordon Tooley. And then homestead style plantings from Virginia to California. All these were aimed at avoiding blossom frosts and lessening brown rot on stone fruit. Interesting discussions followed as to how to utilize cover crops rather than ubiquitous landscape fabric in order to retain fungal connection. Micah's goal in Montana is what you'd expect in more northern zones, and that's the hope of keeping tender cultivars alive for the next growing season. I for one would love to hear more insights about meeting any of these particular horticultural challenges. It may well be that moving those unproductive trees isn't the only option.

Lost Nation Orchard
Zone 4b in New Hampshire

Edited 3 time(s). Last edit at 02/26/2022 06:20PM by Michael Phillips.
Re: Trees in a Hoop House
February 26, 2022 04:18PM
Ah yes, the orchard in a hoop house trick. When I worked at Red Jacket in Geneva NY we had 2 long Haygrove high tunnels that had cherries, apricots and a few plums in them. There were a lot of issues with them principally that they were not installed on the right site (not the tunnel's problem) and the taking down/putting up of the plastic, plus wind, caused huge expenses and labor problems. As well, the plastic filtered out certain wavelengths of light that didn't allow the fruit to color properly. There were also pollination problems. And they did nothing to protect from cold temperatures per se, only frost. The tunnel were 26 x 200' long I believe, 18' high at the peak, and so there also issues with the trees hitting the top of the tunnel even though they were on the most dwarfing rootstocks we could find and pruned to short squat stature.

That said, I was always in love with the hoop house idea, it just needed to be executed properly.

- put it on a good site with well-drained soils.
- make sure the tunnels are sized to what you want to grow. With many more dwarf rootstock options for apples, I could see apples making a better fit, or cherries (but even on G5 roots were too big), but not anything like 'cots or plums on myrobolan.
- optimize the production space - the tunnels aren't cheap and even with a wide spacing you have to account for the ability to work in them, allow for air flow, light penetration, and production. What you lose in vertical capacity needs to be made up for in horizontal capacity, and even in a seemingly spacious tunnel can make for a tight fit.
- irrigation, esp in warm dry climates. What you gain in frost and rain protection, you lose in natural rainfall.
- the plastic should only be on from bud break to fruit set - after that you run the risk of increasing certain fungal diseases (powdery mildew) and not allowing for good air flow or light penetration. **note: there are plastics that do not reduce full spectrum light penetration, but then they also increase shortwave radiation from the sun causing the temperature in the tunnel to skyrocket, so roll up sides or fans can also be a nice addition.
- do not leave the plastic down all winter, wind, snow, rain, etc can really do damage and reduce the overall life span. As well, many plastic do break down in UV and so should be rolled and stored in black plastic.
- Pollination - honeybees and native pollinators do not like to go inside. Using boxed Bumblebees was an option we used, but now I don't recommend that except in closed greenhouses since they can spread viruses and interfere with natural pollination.
- Winter protection: personally I don't think tunnels provide much protection in very cold climates unless there is some modicum of heat applied; and for this reason, in cold climates achieving enough chill units isn't an issue regardless of how you manage the covering.
- Cornell - had a bunch of experiments going to moderate climate issues, some were true tunnels, other were fabric coverings, etc. all interesting, all with some merit, none ever implemented to a great extent in NY.

Anyway, I was very optimistic about using tunnels for tree fruit production, but not so much anymore - at least not from my experiences. They are expensive, time consuming, and add management challenges. Plus I think trees like being outside. Those are my experiences.

Mike Biltonen, Know Your Roots
Zone 5b in New York
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