Frost line considerations for food storage barrel

According to various sources, our frost line is about 31 inches.  I think that would mean that if I wanted to put a food storage barrel in the ground, the top of it would have to be below 31 inches, is that right?

I'm going to be building a 14'x20' greenhouse, so I can grow some food crops that wouldn't otherwise survive our winters.  I don't really want to take up space in the greenhouse for a barrel, so I was thinking of digging a hole for it to go in the ground.  

Does anyone know if the 'frost line' would still be the same?  Obviously, the air in the greenhouse would be warmer, but I'm not going to dig an insulated foundation (where you dig about 3-4 feet deep and line it with insulated foam board), so I'm guessing the freezing temperatures might  migrate into the soil inside the greenhouse, but that's obviously just a guess.

Thoughts?

If it's 31" I'd say that is the absolute worst case scenario, and mainly applies to water line freezing. I'll bet you could get away with the top of the barrel not being that deep, and get creative with your burrying/placement to where you have good access but it's well covered to ideally keep your lid area dry and clean, something you might have to lift up cellar-door style.

I'm not sure the benefits of a bit of extra warmth in the greenhouse is worth losing the plant space if your already skeptical of that. Is there a more convenient location where you can dig and maybe the ground is in a sunny area, too?

Concrete blocks are pretty cheap and might help you somehow incorporating them into your hole. Hollow ones can be packed with gravel and dirt. I'm thinking the access area would need dug out a little more and that's where the blocks might help.

So I guess the warmest part of the barrel would be the bottom where it's at that warm earth level, and heat rises so the whole barrel would benefit from having its sides and probably top insulated somehow more than anything. But I'd imagine that little bit of heat, and the stuff being stored in there will transfer and retain enough heat well enough inside a plastic barrel to where your stuff wont freeze even if done very primitively at the right depths and location.

That's all a theory in my life, haven't tried it myself yet but I plan on doing something like this when the ground isn't frozen or muddy here, too!

The greenhouse would have to be huge to have any effect at that depth so I don't think it would be worth putting it in the greenhouse for that reason, but it might be worth it if you get a lot of snow or even rain, it would be much more pleasant to get things out of the barrel if you don't either have to dig through snow or get soaked while opening it.

Skandi Rogers wrote:The greenhouse would have to be huge to have any effect at that depth so I don't think it would be worth putting it in the greenhouse for that reason, but it might be worth it if you get a lot of snow or even rain, it would be much more pleasant to get things out of the barrel if you don't either have to dig through snow or get soaked while opening it.

Good point about accessing it in the snow or rain.   I hadn't even thought about that aspect.  Thanks for the input about the (lack of) positive impact of the greenhouse.

Cole Tyler wrote:If it's 31" I'd say that is the absolute worst case scenario, and mainly applies to water line freezing. I'll bet you could get away with the top of the barrel not being that deep, and get creative with your burrying/placement to where you have good access but it's well covered to ideally keep your lid area dry and clean, something you might have to lift up cellar-door style.

I'm not sure the benefits of a bit of extra warmth in the greenhouse is worth losing the plant space if your already skeptical of that. Is there a more convenient location where you can dig and maybe the ground is in a sunny area, too?

Concrete blocks are pretty cheap and might help you somehow incorporating them into your hole. Hollow ones can be packed with gravel and dirt. I'm thinking the access area would need dug out a little more and that's where the blocks might help.

So I guess the warmest part of the barrel would be the bottom where it's at that warm earth level, and heat rises so the whole barrel would benefit from having its sides and probably top insulated somehow more than anything. But I'd imagine that little bit of heat, and the stuff being stored in there will transfer and retain enough heat well enough inside a plastic barrel to where your stuff wont freeze even if done very primitively at the right depths and location.

Thanks for the  input.   Sounds like both responses as of right now indicate not much positive benefit of locating it in the greenhouse.

I store my potatoes in a buried metal garbage can. Our frost line here is 30".

Here's what I did:

https://permies.com/t/140268/Garbage-root-cellar-success#1365397

Jan White wrote:I store my potatoes in a buried metal garbage can. Our frost line here is 30".

Here's what I did:

https://permies.com/t/140268/Garbage-root-cellar-success#1365397

Great info, especially the amount of detail. So far, I haven't been very successful with potatoes here, and the wild apples are too wormy to try to store.  But I'm going to keep trying to grow potatoes and especially sweet potatoes.  Good to see the update on your post.  

What crops are you planning to store in your bin? If they're not okay with high humidity, it might be worth putting in some ventilation.

Jan White wrote:What crops are you planning to store in your bin? If they're not okay with high humidity, it might be worth putting in some ventilation.

Not sure yet.   If I can get a good crop of potatoes and sweet potatoes, they will definitely go in there.  I'll have to research other crops.   At one time I grew onions, so I might store those in there.  I usually have a good crop of garlic, which I usually just braid and hang in my basement pantry.  Winter squash is also a possibility.

If I do something for ventilation, wouldn't it just let all of the outside humidity in?   I guess the only thing I'm thinking you mean is having holes in the barrel.  But with frozen ground, snow, rain, I would think having it be airtight would be better...???

Your food is going to give off moisture and you end up with condensation on the inside of the bin. If you have really wet winters, the ventilation might not make a difference I guess. Generally, the cold air outside is going to be drier than the warmer air inside the bin, though.

I wouldn't store onions or squash in a bin like this. Those like it dry. I think sweet potatoes might, too. Definitely not squash or onions, though. I tried storing a couple squash in a bin of wood shavings under the house for the first part of the winter when we weren't getting too much lower than freezing yet. I didn't have room inside for them, but they would have got  frost damage if I'd left them out in the open. It was a big bin of dry shavings and only two squash, but they still started going moldy pretty quickly.

When I grew onions, I braided them like garlic and hung them in an unheated but not freezing garage. It was a fairly dry climate that I was living in at the time. I still had a few onions going moldy where the tops hadn't dried quite enough.

For ventilation, I've seen a piece of PVC pipe with holes in it going up the middle of the bin and out the lid.

Jan White wrote:Your food is going to give off moisture and you end up with condensation on the inside of the bin. If you have really wet winters, the ventilation might not make a difference I guess. Generally, the cold air outside is going to be drier than the warmer air inside the bin, though.

I wouldn't store onions or squash in a bin like this. Those like it dry. I think sweet potatoes might, too. Definitely not squash or onions, though. I tried storing a couple squash in a bin of wood shavings under the house for the first part of the winter when we weren't getting too much lower than freezing yet. I didn't have room inside for them, but they would have got  frost damage if I'd left them out in the open. It was a big bin of dry shavings and only two squash, but they still started going moldy pretty quickly.

When I grew onions, I braided them like garlic and hung them in an unheated but not freezing garage. It was a fairly dry climate that I was living in at the time. I still had a few onions going moldy where the tops hadn't dried quite enough.

For ventilation, I've seen a piece of PVC pipe with holes in it going up the middle of the bin and out the lid.

Well, clearly I have a lot to learn about produce storage (other than the frig).  Thanks for the advice.

Some older homesteaders near me (48" frost depth) take old clay chimney liners (those square or rectangular tubes) and bury them in their yard with the top flush.  They fill them with root crops and cover them with a piece of styrofoam (or a board) and then a foot of straw or leaves.  The snow further covers them.  Then they go dig them up when they need the crops.  

They can only access it once because once the "blanket" is removed they'll freeze out.  So they prefer several caches that they can empty progressively through the winter.

Frost depth is for a cleared area like a driveway.  If you have good snow cover your ground probably doesn't freeze very deep at all.  Heck, go out there now and scrape away some snow to see if it's even frozen.

Also, this is likely only going to work well for true root crops of the northern latitudes - beets, carrots, potatoes, parsnips, rutabagas, turnips, etc.   Sweet potatoes will not do well down there, they need it warmer and dryer so your basement might work fine for them.  Onions can handle the cold but want it drier as well.  

I keep my winter squash in the house, they like it warm(ish) they are kept at about 65F in the utility room. there's only 2 left this year but they have been there since September so 5 months they normally last 7 months just sitting on a shelf there.