Hoop house for winter storage

[WNC Bonsai]

OK, my growing collection is starting to encroach on my truck in the garage where I am overwintering them. So thinking ahead I am considering adding a hoop house for winter storage. Anyone have any designs, suggestions, photos of hoop houses that would do the job?

My gerneral design idea is an unheated and hopefully more or less self-sufficient house that does not need me to daily open and close vents, etc. I have been looking at various self opening vents to install in the top so as to allow excess warm air to vent and of course I expect to periodically go in to see what needs watering.

Other than that it would be built of 1/2-3/4” PCV pipe and poly sheet held on with clips designed for this puropse. Instead of doors at each end I would just gather the excess poly sheet and clip it together. Pots to be placed on the ground and mulched with leaves would help insulate the roots.

Suggestions, comments?

 

[rockm]

Depends on what you're planning to keep in it. I'd bet most of the stuff you've got is probably hardy enough to be overwintered under mulch in the back garden bed...

 

[LanceMac10]

If you do use something of this nature, I would make sure that it has close to zero sun exposure.......


@rockm is pretty accurate in regards to any material you have and it's hardiness.
Went to an overwintering presentation once, the lead was "move to North Carolina"......

 

[WNC Bonsai]

I thought that too but the last couple years we have had these polar outbreaks and our temps have dropped down near 0 at night for almost a week. I start dragging them inside when temps are projected to drop below 20, especially elms and small stuff with very thin branches. The junipers and hinokis I am not concerned about that much as they have stayed outside all winter until last year. Now with this Florida cypress added to the collection I figure it probably needs to have special protection. Out at the arboretum they keep their collection in a big hoop house so I figure if it works for them it should for me, just not as big. Here is a photo:

 

[GGB]

I've made them with a base frame of 2x4s and a few simple ribs of pvc piping. You can get elbows at 45 degrees and +shaped connecteds for a "roof beam?" for added support. that leaves the option of staplng greenhouse plastic to the 2x4 base. In the past I've predrilled and screwed togeteher the pvc. In spring you can back out some screws (or all of them) and store the pieces until next year. You might not have to secure the pipe togther if it's sheltered from the wind but why risk it

 

[WNC Bonsai]

I made a small one for my wife a few years ago when she was germinating some garden seedlings. Used essentially the approach you described with the cemter ridge pole. Inused rebar driven into the ground to stabilize the uprights. We found some clips online that are designed for clipping poly sheet to the poles.

Right now I have a spot next to the house where I keep them when it is not real cold. Brick wall radiates heat and I pile up leaves deep enough to cover the pots. However when it gets this cold I am afraid that the water int the pots will freeze. Maybe a leanto or a slit trench against the house would work as well as a hoop house.

 

[rockm]

I thought that too but the last couple years we have had these polar outbreaks and our temps have dropped down near 0 at night for almost a week. I start dragging them inside when temps are projected to drop below 20, especially elms and small stuff with very thin branches. The junipers and hinokis I am not concerned about that much as they have stayed outside all winter until last year. Now with this Florida cypress added to the collection I figure it probably needs to have special protection. Out at the arboretum they keep their collection in a big hoop house so I figure if it works for them it should for me, just not as big. Here is a photo:View attachment 176281[/QUOTE

Regardless of what the Arb uses, I don't see the need for something like that for anything other than (possibly) the Fla. BC.

I get just as cold as you and I keep everything elm, trident and J maples, hornbeam and other stuff under mulch beds. Have done that for 25 years and we've had sub-zero F stretches in that time. All my BC made it through those extremes, as did cedar elm and some other more southerly trees under mulch in a cold pit with a wood lean to cover open to the air.

The US national arb has a concrete bunker for the most vulnerable bonsai, but leaves a lot of their trees (maples, beech, hornbeam, elm) out on benches in the display area (which is covered by plastic tarps, but still gets pretty cold in there.

The problem with small hoop houses is they are subject to a lot of heat gain in the winter. That would be a problem in your area, as you are also getting the same veryt warm stretches along with the cold.

 

[rockm]

I made a small one for my wife a few years ago when she was germinating some garden seedlings. Used essentially the approach you described with the cemter ridge pole. Inused rebar driven into the ground to stabilize the uprights. We found some clips online that are designed for clipping poly sheet to the poles.

Right now I have a spot next to the house where I keep them when it is not real cold. Brick wall radiates heat and I pile up leaves deep enough to cover the pots. However when it gets this cold I am afraid that the water int the pots will freeze. Maybe a leanto or a slit trench against the house would work as well as a hoop house.

the water in the pots is SUPPOSED to freeze. That isn't going to hurt anything and may even provide some protection against the worst of the cold.

 

[CasAH]

Park the truck in the driveway. Problem solved.

 

[JudyB]

The problem with small hoop houses is they are subject to a lot of heat gain in the winter.

This is a problem that almost all types of overwintering structures have. Even in our colder climate here, I can have issues with warmer sunny days. And my cold house has a actual roof, so to keep the sun heat buildup from being too much of an issue. I also have vent fans and louvers that open an pull colder air thru when it heats up in there. I can't imagine trying to keep a hoop house cool when you have temp swings like you'll have in your area.

 

[cmeg1]

This too,is a question I often ask myself.I thought maybe white plastic to let in light,especially for conifers.Being cold and shut down is probably more important with conifers.
At the new place here I am really just growing a bunch of things out so will just be overwintering in a deep bed of peat moss,always wanted to try this.
Eventually after nursery hoppin’ and actually having bonsai I am kind of leaning on having a shed with electricity going to it for some type of heat and perhaps propane as backup?
Or the white plastic hoop house structure with bonsai sunk in a bed of peatmoss?.......I know you can lose zelkova fine twigs when exposed.
I will have to come up with something eventually.

 

[WNC Bonsai]

This is a problem that almost all types of overwintering structures have. Even in our colder climate here, I can have issues with warmer sunny days. And my cold house has a actual roof, so to keep the sun heat buildup from being too much of an issue. I also have vent fans and louvers that open an pull colder air thru when it heats up in there. I can't imagine trying to keep a hoop house cool when you have temp swings like you'll have in your area.

Yes, I know that warming is an even bigger issue with small structures than larger ones—I ran the biology department green house when I was in college. There are a number of automatic vents made for small greenhouses that work on the principle of expanding gas that drives the pistons and opens the vent, needing no electricity. Maybe I’ll put one of my junipers outside against the hiuse (brick wall) with a leaf blanket and monitor the soil max and min temps for the next month just to see how bad things can get. I can contend with keeping a few sensitive plants in garage, just not a whole collection.

 

[Dav4]

Yes, I know that warming is an even bigger issue with small structures than larger ones—I ran the biology department green house when I was in college. There are a number of automatic vents made for small greenhouses that work on the principle of expanding gas that drives the pistons and opens the vent, needing no electricity. Maybe I’ll put one of my junipers outside against the hiuse (brick wall) with a leaf blanket and monitor the soil max and min temps for the next month just to see how bad things can get. I can contend with keeping a few sensitive plants in garage, just not a whole collection.

Most junipers would laugh at a typical Asheville winter. My RMJs among others have sat on their stone benches this winter without protection from the temps that have fallen near 10F and have stayed below freezing for weeks without issue. Personally, I think a hoop house would be nice to get a head start on cuttings and re-pots but is unnecessary for general winter protection unless you plan on working your trees through the winter or you're keeping borderline hardy material like the FL grown cypress (which would still be fine mulched up against the northern foundation of your house).

 

[GrimLore]

Suggestions, comments?

Build or buy a nice shelf system to increase the capacity of your garage... Far more stable then a Hoop House and healthier for the plants. In your area I am pretty certain a hoop house will invite other problems such as fungal...

Grimmy

 

[JudyB]

Yes, I know that warming is an even bigger issue with small structures than larger ones—I ran the biology department green house when I was in college. There are a number of automatic vents made for small greenhouses that work on the principle of expanding gas that drives the pistons and opens the vent, needing no electricity. Maybe I’ll put one of my junipers outside against the hiuse (brick wall) with a leaf blanket and monitor the soil max and min temps for the next month just to see how bad things can get. I can contend with keeping a few sensitive plants in garage, just not a whole collection.

I used to have a passive greenhouse too, warmed with tubes of sun heated water, and cooled with auto vents, they were driven by beeswax that expanded and contracted in the heat/cold. Unless you have a way to drive the hot air out, I don't think that vents work very well, and not at all if the outside air temps are above the temp you want to keep for dormancy. Even here I've been thinking of doing a cool bot, (think like a simple chiller cooler) but thankfully this winter has not had the warmer temps that we've had the past few years.

 

[M. Frary]

the water in the pots is SUPPOSED to freeze. That isn't going to hurt anything and may even provide some protection against the worst of the cold.

Mine are frozen right now. Have been since Thanksgiving and will stay that way until April sometime.
No problems.

 

[boonefrog]

What did you end up deciding for this @Cofga ? I'm also in Asheville area and have been doing tons of cuttings, germination, buying plugs and working with other small containerized material where I think a low hoop structure or some other kind of winter wind protection might be necessary. My bigger stuff I'll likely continue to heel into the ground a bit under the deck but for this new stuff I'm grappling with some of the same questions you did...

 

[WNC Bonsai]

What did you end up deciding for this @Cofga ? I'm also in Asheville area and have been doing tons of cuttings, germination, buying plugs and working with other small containerized material where I think a low hoop structure or some other kind of winter wind protection might be necessary. My bigger stuff I'll likely continue to heel into the ground a bit under the deck but for this new stuff I'm grappling with some of the same questions you did...

The last few years have increased the number of times we get warm spells in mid winter and early spring deep freezes that result in widespread damage to plants in this area. Consequently I more frequently am having to haul my trees in and out of the garage after they break dormancy or are repotted plus my back is not getting any better. So I finally have decided to put up a small green house. Costco has a nice 6’7” x 9’7” cedar framed kit with double pane polycarbonate glazing that is reasonable and they will deliver for free. So as soon as I decide where to put it I will hit the buy button. It will likely only be used for trees that are marginal and for those that break dormancy in late winter/early spring and after repotting. The reality of this hit me a few weeks ago when we were expecting that first big freeze. As I was lowering a big bald cypress to the ground I pulled a muscle in my thigh and ended up sitting on the ground with the tree in my lap. Hauling it and a few other big boys and girls up and down the hill to my garage several times each winter was not going to work anymore so the search began in earnest on YouTube for a solution and this greenhouse kit won out. I figure I can add a small solar powered fan and more vents for extra cooling, and black plastic jugs filled with water for heat retention when needed. Its either that or sell my collection.

 

[Deep Sea Diver]

Seems a wise step. At the very least it will save a hernia operation. One of our friends just had to get one- caused by humping his trees up and down hill.

We’ve a couple 8x6 cold greenhouses running with remote temp/humidity sensors. Also fan/heater on thermostat switch/auto vents. (btw @Pitoon self constructed a hoop house. Both are shown in this resource in ‘case studies.’

Seems to add about 1.5 - 2 months to the growing season. Allows us to work trees later in the year and protect these afterwards… and spaces out the work similarly.

imho ours save an awful lot of issues, including fine branch loss from elements.

Just my two bits..

cheers
DSD sends

 

[Pitoon]

@Deep Sea Diver I just built a larger one a couple of weeks ago. This one is 49in tall x 6ft wide x 20ft long. It's about 90% filled now. Today I closed the sides as we're expecting below 32° these next couple of days. Once I see the temps go back up I'll open the sides again.