What do I need to know about using a winter shelter?

[IllinoisSam]

I'm putting a shelter together, identical to the attached photos. I have about 40 plants. I'm in Zone 6, almost Zone 7, and can expect 0 degrees F once or twice a winter. For the last few years I would just set my trees on the ground and pile up pine needles over the pots, which seemed to work fine but I thought I'd up my game a little. Once I'm finished building, the plants will be under cover, in an area partially shaded by pine trees.

So, how do I manage this crude greenhouse? Do I just put them in, cover it and bring them out at the end of February? Should I open it up on warm days? What about watering? I would appreciate anyone's experience.

Thanks.

 

[Colorado]

I’d be worried about the plants drying out way too much if you just leave them in there until February.

 

[rockm]

If it ain't broke don't fix it.

Seriously, "upping your game" with an enclosure isn't really helping your trees. It's complicating things for no real reason. Watering will be a big issue as will heat gain on warmish days, as will rodents I'd bet. If you've had success with mulching them on the ground why shift to a completely different untried "solution?"

 

[penumbra]

Is that fabric covering your hoops?

 

[dbonsaiw]

Seriously, "upping your game" with an enclosure isn't really helping your trees. It's complicating things for no real reason. Watering will be a big issue as will heat gain on warmish days, as will rodents I'd bet. If you've had success with mulching them on the ground why shift to a completely different untried "solution?"

What he said. I've used a pop up greenhouse in the past and not sure it really did anything other than protect from wind. It was a walk in, so watering was easy, but other than that no real purpose. I have a similar amount of trees and would need to purchase an even larger greenhouse this year. I experimented and followed Rockm's advice and mulched some of my trees in last year without the tent. They sat outside unprotected and even covered in ice for a long period. They were all fine come spring. (Had issues with some of the trees in the tent, but I did so many things wrong that I can't blame it on the tent).

Here's my setup for this winter. I've got maples, elms, redwoods and other species in there. I went a little crazy with the mulch - its 14'X8'Xalmost 10". Trees are buried in there at different depths depending on the size of the pots.

Winter still freaks me out and I try to remind myself that they are trees and have evolved to be fine outside (even in a pot, with some adjustments). For what it's worth, my son did nothing with his trees last winter. They just sat on a folding table and experienced winter. They all woke up and grew nicely this season.

I would recommend mulching the pots and then using proper covers at night or when it's brutal cold, uncovering them otherwise. Not sure what you have covering them, but some sort of breathable frost cloth would likely work and not interfere with airflow and watering.

 

[penumbra]

In defense of fabric like frost blankets for your hoops or enclosures, there are many plants I could not grow otherwise. I don't coddle my plants but when I am growing many zone 7 plants in a zone 6 environment, I offer them a little extra. I will be covering my hoops this afternoon and tomorrow with fabric. I also put fabric on the lids of my coldframes to help moderate temperature swings and help to control heat build up. It has been working for me now several years and I expect it will this year as well.
I am curious as to what the op has used to cover his hoops. It looks like fabric. However, looking at his plants before covering, there are a lot of things there that I feel should not be covered and should be heeled in mulch, leaves etc. Now if I saw a group of young Japanese maple and a group of Satsuki azaleas, I would feel it is a good choice. I am covering my young maples and satsuki now.

 

[IllinoisSam]

In defense of fabric like frost blankets for your hoops or enclosures, there are many plants I could not grow otherwise. I don't coddle my plants but when I am growing many zone 7 plants in a zone 6 environment, I offer them a little extra. I will be covering my hoops this afternoon and tomorrow with fabric. I also put fabric on the lids of my coldframes to help moderate temperature swings and help to control heat build up. It has been working for me now several years and I expect it will this year as well.
I am curious as to what the op has used to cover his hoops. It looks like fabric. However, looking at his plants before covering, there are a lot of things there that I feel should not be covered and should be heeled in mulch, leaves etc. Now if I saw a group of young Japanese maple and a group of Satsuki azaleas, I would feel it is a good choice. I am covering my young maples and satsuki now.

Those beautiful trees belong to one of the guys in our club, they are not mine. I'm just monkey see - monkey do. He has been doing bonsai for 40+ years. He normally stacks the pots and covers it all with a frost blanket and poly but this is his first year with a "greenhouse". He keeps his trees under an overhang in the winter, and says he only has to water once or twice in the winter. He uses a fungicide with the first watering before he covers them.

And regarding the pine needles, for some reason I don't have very many this year, so not my home grown mulch is not available anyway this year.

 

[Deep Sea Diver]

Whoa thar folks!!

Frankly I wouldn’t nay say any idea for wintering over. Each has its place and can be effective. But one has to understand the limitations of each design and accommodate accordingly.

In fact it takes a couple three years of experience to understand how to maximize each design. We have a cold frame, greenhouse, trees mulched in the ground, trees in the garage and trees just in pots growing in the ground. I’ll still learning the nuances of each method to e end up with that are unharmed by winter, robust and ready to work for a full Bonsai year.

Hoop house designs work. @Pitoon has many of his trees in a homemade hoop house and @kale actually uses a window vent.

OP is giving an honest and decent try. so let’s not shoot him down, but work to provide helpful ideas on how to assist him with the nuances his design.

Here’s a resource document that will help you understand some of the planning needed and designs used. Use the index once you download.

https://www.bonsainut.com/resources/overwintering-bonsai-–-theory-planning-and-case-studies-azalea-focus.49/

Cheers
DSD sends

 

[dbonsaiw]

OP is giving an honest and decent try. so let’s not shoot him down, but work to provide helpful ideas on how to assist him with the nuances his design.

Ditto. Definitely not my intention to shoot anything down. I'm pretty lost on this myself and open to any ideas.

And after seeing frost cloth advertised as good down to 38 degrees, well I'm even more lost considering things freeze below 32.

 

[Deep Sea Diver]

Normally frost cloth is used as a bridge for crops between fall and winter, also from winter to spring. It lets rain and heat in, trapping the long infrared rays at night, delaying frost. It’s very effective.

It shouldn’t touch the crops though, to be most effective.

I can see it also used by Bonsai hobbyists to moderate to local climate, taking the edge off of the the weather, and easing trees into winter dormancy. Likely only good for spring frost coverage on the other end once trees are out of dormancy…

Other Thoughts?

Cheers
DSD sends

 

[penumbra]

Normally frost cloth is used as a bridge for crops between fall and winter, also from winter to spring. It lets rain and heat in, trapping the long infrared rays at night, delaying frost. It’s very effective.

It shouldn’t touch the crops though, to be most effective.

I can see it also used by Bonsai hobbyists to moderate to local climate, taking the edge off of the the weather, and easing trees into winter dormancy. Likely only good for spring frost coverage on the other end once trees are out of dormancy…

Other Thoughts?

Cheers
DSD sends

I appreciate your thoughts. While I am not analyzing it, I have always been pleased with the results I am getting. I appreciate that it does help hold in some heat but the most valuable thing about it IMO is the temperature moderation. Covered all my smaller JM again like in years past. I haven't done the satsuki bed yet because I ran out of clips. I will finish on Friday.

 

[sorce]

You reckon the trees are having conversations about wrapping our heads in plastic bags?

They need all those senses to not be confused, they need to feel it all, see the sun from the same angle, feel the fronts coming in.

Don't deprive them of their necessities, or they'll die!

Sorce

 

[Colorado]

You reckon the trees are having conversations about wrapping our heads in plastic bags?

Sorce

Only some of us!

 

[Pitoon]

Wintering hoophouses do work and are extremely easy to set up and take down, at least mine is. I keep all my young stock and not so cold hardy plants in mine over the entire winter. On warmer days I open one side to vent it out. I water maybe once a month.

The most important thing to keep in mind when using a hoophouse over winter is to use an opaque plastic sheet. Preferably a wintering opaque plastic 5mil film, these will last you 3-5yrs easily maybe more if the plastic doesn't get beat up. Clear plastic will allow the light to pass through converting your hoophouse into a greenhouse. Don't use fabric as a covering for your hoophouse. The fabric will allow rain and wind to pass through.

 

[Deep Sea Diver]

Those beautiful trees belong to one of the guys in our club, they are not mine. I'm just monkey see - monkey do. He has been doing bonsai for 40+ years. He normally stacks the pots and covers it all with a frost blanket and poly but this is his first year with a "greenhouse". He keeps his trees under an overhang in the winter, and says he only has to water once or twice in the winter. He uses a fungicide with the first watering before he covers them.

Sounds like you have some expert local area advice. Likely you can’t go too far wrong following it. @penumbra has good points about the tree hardiness and care and has experience with frost blankets too.

Personally I would water a just tad more and error on the side of at least mulching in the lot under that cover. Yet his trees, his rules .

I appreciate your thoughts. While I am not analyzing it, I have always been pleased with the results I am getting. I appreciate that it does help hold in some heat but the most valuable thing about it IMO is the temperature moderation. Covered all my smaller JM again like in years past. I haven't done the satsuki bed yet because I ran out of clips. I will finish on Friday.

Awesome!

Can you please shoot some photos either here or by PM of your set up? I’m interested in checking out your layout. Apologies if you’ve previously posted these.

cheers
DSD sends

 

[kale]

Thanks for the mention @Deep Sea Diver! Here’s my window well this year. The trees are lots bigger this year so pretty crammed in there. I cut off long shoots otherwise they’d be hanging out but it wouldnt be a problem if they were.

 

[Shogun610]

Most of the stuff is in a wire fence to keeep critters out .. also set traps .. next to house to get that head form home and ground, some in-n-out delicates/climatizing tees , and some that are fine where they are. Use your best discretion.. snow helps .. hoop house works just keep eye on watering more often than if left uncovered. Leaves help too.. which is my already final phase. Good luck

 

[Potawatomi13]

Relocate to Zone 8! No worries.

 

[penumbra]

Relocate to Zone 8! No worries.

How are your larches and firs doing?

 

[Potawatomi13]

No Larch. Doug Fir okey dokey.