Overwintering in a greenhouse?

[Eckhoffw]

Biggest concern is - will it be able to be used for growing vegetables this year, or will it get so hot they torch? We will see...

Also my wonder.
I’m thinking of just making mine a hot loving plant house. Cactatarium + succulent home.

 

[Colorado]

I have a heater on a thermostat at 3-5 c so things don’t freeze.

What heater and thermostat are you using? Sounds like a great setup!

 

[Robertji]

What heater and thermostat are you using? Sounds like a great setup!

I have an Inkbird 308 temperature controller and a 1500 watt portable heater from a local big box store. Both have worked well for three years now. I have a backup heater just in case and for when it gets really cold. We get a couple nights a winter of minus 30c temps and with both heaters I can keep the greenhouse right around zero.
Canada Bonsai has a great handout called Winters in Canada in their resource section of the website that I referenced when I was setting up. I found it a big help.

 

[Eckhoffw]

So far, nothing is moving in the greenhouse. Some maple are swelling and perhaps the forsythia. I’m hoping that is a good sign as we are into spring now.
Plenty of below freezing days to come I imagine. - Low of 14 F. Tomorrow night-

I continue to put snow on the pots as needed. So far, most pots are still frozen to the ground.

 

[Deep Sea Diver]

David Crust came over to the shop today to donate the Hoover Larch. We chatted a bunch about his “cold house” and other stuff.

This discussion reminded me that David and Ryan N recently had a great discussion on Asymmetry in which he described his winter care and work flow. If folks in the cold haven’t yet heard this interview, it was a good one!

cheers
DSD sends

 

[badatusernames]

I've taken the greenhouse opaque sheeting off of mine now to get a little more light in and have it sitting around 45 degrees since everything was flushing out

I still have shade cloth up but debating taking it down until hotter suns come

 

[Eckhoffw]

Ok. I’m going to use a life line here and ask @Deep Sea Diver if this Peking cotoneaster needs to get more protection now that it’s begun to leaf out. ??Temps will get well below freezing for awhile here. I could put it in my temp controlled cold frame?
Thanks

 

[Deep Sea Diver]

Gosh Peking Cotoneaster is rated at -40F.

So it’s going to depend on if you did any root work on it or it’s showing signs of Ill health,

If you are uncertain. Protect.

Cheers
DSD sends

 

[Eckhoffw]

Gosh Peking Cotoneaster is rated at -40F.

So it’s going to depend on if you did any root work on it or it’s showing signs of Ill health,

If you are uncertain. Protect.

Cheers
DSD sends

Thanks. Yeah. No repot recently. I was just not sure if any new growth would be susceptible to die back.
Night Temps are in the 20s still for awhile. the greenhouse provides protection, but temps still reach outside temps in the middle of the night.

 

[Deep Sea Diver]

I get it. It’s-a tweener thang.

Likely you are best off just playing it safe and tossing the tree in the greenhouse. If there is room. At the least it will moderate the temperatures and keep it out of the wind and weather, which will help a real lot.

Cold frame would be next option for similar reasons.

Cheers
DSD sends

 

[Eckhoffw]

After the 6” of wet snow 10 days ago, we now have beautiful weather (65-80 F.) for at least a week.
Greenhouse plants were pulled from their beds and placed outside on the benches or up on the benches in greenhouse.
So far things look good.
My BIG question at this point is, can/would it be beneficial to leave some of the deciduous trees in the warmer greenhouse?
Im weighing the UV protection of the greenhouse VS. the high heat inside.
Today it hit 80 F. But was 93 in the greenhouse.
Is this toooo hot?
Thanks!

 

[Eckhoffw]

It occurs to me that I need to get fans if I plan on anything surviving in there over the summer.
I plan on getting a solar powered fan to be installed in the south peak. Also, a battery op floor fan.
Wish I could run power out there, but I would have to get a new breaker panel to do so.

 

[Deep Sea Diver]

After the 6” of wet snow 10 days ago, we now have beautiful weather (65-80 F.) for at least a week.
Greenhouse plants were pulled from their beds and placed outside on the benches or up on the benches in greenhous
So far things look good.
My BIG question at this point is, can/would it be beneficial to leave some of the deciduous trees in the warmer greenhouse?
Im weighing the UV protection of the greenhouse VS. the high heat inside.
Today it hit 80 F. But was 93 in the greenhouse.
Is this toooo hot?

Well done!

Yes it is not so good. once the temps creep into the 90’s most trees slow down… likely a bit before that…

Most of our azaleas are in the greenhouses or cold frame right now. during the days the doors are open and fans continue their 24/7 duties. (btw a fan is a must have… doesn’t have to be fancy) I took some of the azaleas out…they are 2+ weeks ahead of those in the cold frame and 2 more vs those outside. Then the nighttime the temps dipped again. Forecast to be the same low temperatures for the next three days, so in they go.

Maples are a different story. You can keep them in the greenhouse as long as the temperatures are decent inside and you’ll gain a couple weeks or so growing out in spring. Same in fall unless the fall ampunt of daylight trigger overrides the temperature trigger. Once the temps outside are decent, not much advantage.

Wondering if you left the greenhouse door open during the day? Ours are open during daylight now.

cheers
DSD sends

 

[Eckhoffw]

Well done!

Yes it is not so good. once the temps creep into the 90’s most trees slow down… likely a bit before that…

Most of our azaleas are in the greenhouses or cold frame right now. during the days the doors are open and fans continue their 24/7 duties. (btw a fan is a must have… doesn’t have to be fancy) I took some of the azaleas out…they are 2+ weeks ahead of those in the cold frame and 2 more vs those outside. Then the nighttime the temps dipped again. Forecast to be the same low temperatures for the next three days, so in they go.

Maples are a different story. You can keep them in the greenhouse as long as the temperatures are decent inside and you’ll gain a couple weeks or so growing out in spring. Same in fall unless the fall ampunt of daylight trigger overrides the temperature trigger. Once the temps outside are decent, not much advantage.

Wondering if you left the greenhouse door open during the day? Ours are open during daylight now.

cheers
DSD sends

Very good information! Thanks soo much for all your help!
Yeah, doors were/are almost fully open.
I gotta get the fan, and perhaps with the shade cloth put back up, it will hospitable for the spring at least.

 

[WNC Bonsai]

I am currentky considering a small greenhouse too. Not so much for overwintering as much as for protecting trees in late winter/early spring. I am expecting to have to repot about 2/3 of my trees this year and need a way to protect them from freezing afterwards. We also now regularly see extended warm spells in late winter/early spring which kickstart the trees to break dormancy and bud out. This is now commonly followed by the dreaded polar vortex outbreaks which drop temps down into the upper 20s leading to extensive damage even on trees in the ground. I have gotten to the point where doing the bonsai two step is taxing so need some way to protect them. Finally I am transitioning to smaller shohin sized trees which with their smaller pots need more protection. So this thread has been a big help for ideas on keeping a winter green house cool.

 

[Eckhoffw]

I am currentky considering a small greenhouse too. Not so much for overwintering as much as for protecting trees in late winter/early spring. I am expecting to have to repot about 2/3 of my trees this year and need a way to protect them from freezing afterwards. We also now regularly see extended warm spells in late winter/early spring which kickstart the trees to break dormancy and bud out. This is now commonly followed by the dreaded polar vortex outbreaks which drop temps down into the upper 20s leading to extensive damage even on trees in the ground. I have gotten to the point where doing the bonsai two step is taxing so need some way to protect them. Finally I am transitioning to smaller shohin sized trees which with their smaller pots need more protection. So this thread has been a big help for ideas on keeping a winter green house cool.

Thanks for the heads up/reminder to check this thread.

To reply to this post, I will happily say that I’ve noticed good things in terms of early dormancy and protection.

I feel that having The trees on the ground and mulched in with wood chips, Has done a good job At regulating the rootball temps.

I’ve made sure that they were moist before freezing, and have watered them when warmer temps come around. The mulch gets watered as well at this time.

Currently, I’ve been keeping an eye out for anything starting to push.
We’ve had abnormally warm weather for the last three weeks, And so far so good!

55 degrees tomorrow! February in Minnesota.

 

[JackHammer]

Thanks for the heads up/reminder to check this thread.

To reply to this post, I will happily say that I’ve noticed good things in terms of early dormancy and protection.

I feel that having The trees on the ground and mulched in with wood chips, Has done a good job At regulating the rootball temps.
View attachment 527522View attachment 527525View attachment 527526View attachment 527524View attachment 527523
I’ve made sure that they were moist before freezing, and have watered them when warmer temps come around. The mulch gets watered as well at this time.

Currently, I’ve been keeping an eye out for anything starting to push.
We’ve had abnormally warm weather for the last three weeks, And so far so good!

55 degrees tomorrow! February in Minnesota.

... are those conifers stying in the greenhouse?

I have a slightly smaller greenhouse and while it stays warmer, I found it really hard to regulate the temperature and watering conditions. The hose is frozen over, and all my buckets are bricks of ice. I opted to keep my trees outside the greenhouse after trying it for a few weeks.

I am starting to move my trees back to their spots in the middle of the yard. The sensitive trees are still hanging out under the bushes.

I was most worried about my azalea(s) and it looks like those did ok without the greenhouse for the second year.

 

[Eckhoffw]

... are those conifers stying in the greenhouse?

I have a slightly smaller greenhouse and while it stays warmer, I found it really hard to regulate the temperature and watering conditions. The hose is frozen over, and all my buckets are bricks of ice. I opted to keep my trees outside the greenhouse after trying it for a few weeks.

I am starting to move my trees back to their spots in the middle of the yard. The sensitive trees are still hanging out under the bushes.

I was most worried about my azalea(s) and it looks like those did ok without the greenhouse for the second year.

My smaller conifers are in there. Probably not necessary with the warmer winter.
However, 3 -4 weeks ago it was -10 to -15 degrees actual temps for a week straight.
I’d rather keep trees in small pots mulched in the greenhouse than having them buried in the yard. Also. We have no snow. 2” total so far this winter. Therefore, nothing to bury them in and protect from drying winds.

 

[JackHammer]

My smaller conifers are in there. Probably not necessary with the warmer winter.
However, 3 -4 weeks ago it was -10 to -15 degrees actual temps for a week straight.
I’d rather keep trees in small pots mulched in the greenhouse than having them buried in the yard. Also. We have no snow. 2” total so far this winter. Therefore, nothing to bury them in and protect from drying winds.

It isn't the cold, I would be afraid of the heat in the greenhouse. But I guess it depends on the situation.

 

[Eckhoffw]

It isn't the cold, I would be afraid of the heat in the greenhouse. But I guess it depends on the situation.

Definitely. Precautionary measures have to be made. I do believe that the moist mulch (wood chips) I have surrounding the pots, is a huge factor. It Freezes at night, and keeps the Soil and roots cold during the day.