Cold frame - looking to purchase

[Mikea454]

zone 6b - new england, first winter with bonsai. looking to buy a cold frame (had planned to make one, but running out of time).

any recommended brands or models or sites to use?

I'll need about 48"x24x24 to fit all my conifers
I'll keep the deciduous in the garage.

thanks for the recommendations!

 

[Aaron the Great]

Good question, I have been thinking about making a cold frame so I will keep track of this post. This is a really great place to be for starting out with bonsai. So much valuable information freely shared within these threads.

 

[cody94withrow]

If not I'm seeing people using hay bales to border and putting old windows over top of it, but I may end up framing some greenhouse plastic between some planks. It seems like it'd be super easy.

 

[Bonsai Nut]

If not I'm seeing people using hay bales to border and putting old windows over top of it

You don't need a window - in fact a window would be bad. Just use a piece of plywood, metal roofting, etc.

 

[cody94withrow]

You don't need a window - in fact a window would be bad. Just use a piece of plywood, metal roofting, etc.

idk all the ones I saw on google used like scrap windows, single panes i think

 

[Paradox]

Im going to second what @Bonsai Nut said.
Do Not put a window over your cold frame. That might be ok for someone starting veggies early but could create a huge problem for bonsai
The glass will act like a greenhouse and could warm up the cold frame too early in the season causing trees to leaf out too early. This followed by a freeze can kill your trees.

As for purchase, I am not aware of any prefab cold frames that I would use for bonsai. A hoop house has the same problem as the piece of glass, they tend to heat up too much. All the ones I see online have glass/plastic tops or sides that will act like a greenhouse. Great for starting veggies early, VERY BAD for bonsai.
Mine is made from cinder blocks that form a box against the north side of my house. North side because I do not want sun on those trees in the winder for the aforementioned problems with warming it up too much when I want the trees to stay dormant.

A fast cold frame can be as simple as hay bales that form a box covered with plywood when you need to. I dont cover mine unless it will drop below 30, which could easily happen in Mass.
The problem with hay bales is that you will probably only get one season out of them as they will fall apart but will work in a pinch

Other methods are plywood walls held in place with stakes. However plywood will only last a year or two as it will eventually delaminate when it gets wet

Just get whatever you can for now and try to plan better next year.

Here is my cold frame:

 

[cody94withrow]

Im going to second what @Bonsai Nut said.
Do Not put a window over your cold frame. That might be ok for someone starting veggies early but could create a huge problem for bonsai
The glass will act like a greenhouse and could warm up the cold frame too early in the season causing trees to leaf out too early. This followed by a freeze can kill your trees.

As for purchase, I am not aware of any prefab cold frames that I would use for bonsai. A hoop house has the same problem as the piece of glass, they tend to heat up too much.
Mine is made from cinder blocks that form a box against the north side of my house. North side because I do not want sun on those trees in the winder for the aforementioned problems with warming it up too much when I want the trees to stay dormant.

A fast cold frame can be as simple as hay bales that form a box covered with plywood when you need to. I dont cover mine unless it will drop below 30, which could easily happen in Mass.
The problem with hay bales is that you will probably only get one season out of them as they will fall apart but will work in a pinch

Other methods are plywood walls held in place with stakes. However plywood will only last a year or two as it will eventually delaminate when it gets wet

Just get whatever you can for now and try to plan better next year.

Here is my cold frame:

View attachment 573102

ohhh I got it I didn't think it'd get so warm it'd keep them from going into dormancy.

I like the bales idea because I can use em in my compost.

 

[Paradox]

ohhh I got it I didn't think it'd get so warm it'd keep them from going into dormancy.

I like the bales idea because I can use em in my compost.

Its more like it could keep them from getting proper dormancy and/or force them out of dormancy too early

 

[cody94withrow]

Its more like it could keep them from getting proper dormancy and/or force them out of dormancy too early

fair enough in fact that makes it easier anyway.

 

[MoriLZ]

Any suggestions to place under the plants if you have to keep them on concrete (townhouse)?

 

[Mikea454]

Any suggestions to place under the plants if you have to keep them on concrete (townhouse)?

I was just gonna layout a sheet of cheap weed guard, then put then a little mulch under and around the pots. hoping the weed guard will make easy cleanup.

 

[Mikea454]

Im going to second what @Bonsai Nut said.
Do Not put a window over your cold frame. That might be ok for someone starting veggies early but could create a huge problem for bonsai
The glass will act like a greenhouse and could warm up the cold frame too early in the season causing trees to leaf out too early. This followed by a freeze can kill your trees.

As for purchase, I am not aware of any prefab cold frames that I would use for bonsai. A hoop house has the same problem as the piece of glass, they tend to heat up too much. All the ones I see online have glass/plastic tops or sides that will act like a greenhouse. Great for starting veggies early, VERY BAD for bonsai.
Mine is made from cinder blocks that form a box against the north side of my house. North side because I do not want sun on those trees in the winder for the aforementioned problems with warming it up too much when I want the trees to stay dormant.

A fast cold frame can be as simple as hay bales that form a box covered with plywood when you need to. I dont cover mine unless it will drop below 30, which could easily happen in Mass.
The problem with hay bales is that you will probably only get one season out of them as they will fall apart but will work in a pinch

Other methods are plywood walls held in place with stakes. However plywood will only last a year or two as it will eventually delaminate when it gets wet

Just get whatever you can for now and try to plan better next year.

Here is my cold frame:

View attachment 573102

thank you for all the good advice. we've had some really mild winters here in mass, maybe a couple weeks all winter under 30, and maybe 1-4 days a year that dip under 15F. My question is, my my pines, junipers, jap. Holly, and cedars - if I get 5-10 days in a row that are 20F, can I really keep them covered without sunlight for all that time?

 

[Paradox]

thank you for all the good advice. we've had some really mild winters here in mass, maybe a couple weeks all winter under 30, and maybe 1-4 days a year that dip under 15F. My question is, my my pines, junipers, jap. Holly, and cedars - if I get 5-10 days in a row that are 20F, can I really keep them covered without sunlight for all that time?

Yes you can keep them covered for a couple of weeks.

Before I built the cold frame, I kept my trees in a dark garage all winter. I've also kept the cold frame covered for weeks with no issues

 

[Mikea454]

i was going to keep my deciduous the garage, but shocked you can put the japanese pines in there. thanks again buddy, really appreciated

 

[Paradox]

i was going to keep my deciduous the garage, but shocked you can put the japanese pines in there. thanks again buddy, really appreciated

I stopped using the garage and built the coldframe because the garage stayed too warm and my tree leafed out too early

 

[Mikea454]

luckily my unattached shed has a screen door and a window. I actually just picked up a new thermometer to start tracking the garage temp - may have been one you recommended - one of the smart nutters