Modify Chest Freezer to Hold at 32-34 Degrees F

I want to modify a chest freezer for long term storage at 32-35 degrees F.

Any techies out there who can help.


A thermostat linked below looks like a good place to start.


Maybe not what you are looking for, but I bought a Cool Bot controller and a new 12,000 btu window ac and made a cold room for storing nursery stock. Only have 1 year of experience with it but complely satisfied so far.

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I have the one Fruitnut linked to… It works great. I use a small chest freezer i know longer need. I fill it with apples and/or pears.

We have also converted a huge chest freezer for use as a refrigerator. Best thing ever. We use a external thermostat.

I have used an external thermostat similar to the one Fruitnut linked in a chest freezer before. Works well, except that you need to plan on removing the condensed water which will build up every so often.

One thing I’d suggest/did, is get the electronic version of that thermostat. A bit more expensive, but it has wires to an electronic sensor instead of the fluid filled bulb and thin copper tube, quite a bit stronger and can take more flexing. Regardless of which you choose, duct tape the sensor wire in place on the freezer, that will keep it from falling out sometime with dire results (freezing).

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I have not tried it, but I understand that home brewers do this frequently and you will find a number of suggestions and tutorials from that community. Here is one example

Thank you all for all the information.


Use one without auto-defrost and get a thermostatic power shut-off from a company that sells brewing supplies. It will automatically shut off your freezer at the temp you set but there is more than ideal range (before the freezer turns back on) but it’s the best you can do on a low budget. Actually, I have one I could sell you. I bought a chest freezer for the purpose, but ended up using it to store frozen fruit instead. It is half full with blueberries and getting the rest of the way with nectarines. I keep enough apples to get me through winter in a small fridge.


Other than the temperature and humidity setting and requirements (that was going to be my next set of questions) what else is there to consider?

Thanx, but I already have the freezer and will be looking at one of the digital controllers.



No, it is the thermostatic controller I have in surplus. I need the freezer! I don’t know anything about humidity setting- I have a cheap freezer that needs annual defrosting.

I want to revive this topic and ask some additional questions about storing fruit/veggies in converted freezer.

  1. What is the best controller? I see several types on amazon ranging from $25 to $65 and they all have about 4% of one star review with scaring stories about killed eggs, plants and fish. So it is kind of difficult to decide which one is better.
  2. Where in the freezer you put the probe? Bottom, middle, top?
  3. Do you store your produce in tight freezer bags or somehow else?
  4. Is it OK for the produce(In the bags or not) to touch converted freezer bottom or walls, or you need to have some air between the cooling part of the freezer and produce?
    We just bought 3.5 cu foot freezer for $30 on Craig’s list, now I need to convert it to storage.

Galinas, I only used the set up for apples when I had two freezers (one for apples at 32-38, one for meat at -19). The apples (mostly Arkansas Black, some Goldrush) did touch the inside walls and there was no damage well into May. I can not promise it, but what FN suggests above works well. These are near passive instruments, really difficult to break. Mine was bought at a brewing store. My guess is that a freezer with this mod. would work equally well for winter storage of roots and cabbage (but do not mix them with apples).

On another matter since you are from there: with my daughter we are thinking of going to the World Cup. Where to go? We want to see country life and monasteries, but we will also be based in Moscow. I can read russian and spit out some broken sentences.

ps. it does not matter where you put the probe. the apples were in paper bags for easier extraction, but to fill gaps I put also apples in direct contact with the wall.

If you ask me, I would definitely go to St. Petersburg - I love this city much more than Moscow, though I lived in Moscow. There is a train that can bring you from Moscow to St. Petersburg in just few hours, but you will need a place to stay there - there are more things you want to see there than you can see in one day. If you want to stay in and around Moscow you can take bus tour on “Golden circle of Russia” - it is a set of smaller towns around Moscow with monasteries and museums. Some tours include one-two nights stay in the hotel on the road. In Moscow itself, if you like art - visit Pushkin’s museum, and Tretiyakov’s Gallery. There are also a lot of working churches in Moscow. If you want to see “insider’s” Moscow or suburb, I can ask my daughter(she leaves there now, assuming she still will be there) to take you for a day excursion. Send me PM when you ready, and I can help you more…

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I use the thermostat Fruitnut linked. I have it set to 34F. The temperature fluctuates between 32 and 41 since it’s an on/off type control. I put cardboard against the freezer walls since the walls get colder. So far I’ve got apples, pears, pecan, persimmon, honey locust, jujube, hican, pawpaw and mulberry growing fine with scion wood stored this way. The freezer was free from a coworker so it worked out great for me. It’s about 30 years old and I bet there are another 30 years to go.

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You will be very happy with the freezer solution. I bought a 5.5 cu ft last year and this year I’ll probably add a 7.5 cu ft. and keep the 5.5 as a true freezer for all the nectarines I hope to save from all the “rots”. (You hear @alan ? I was able to eat one frozen nectarine this winter and my mouth is still watering )

An Optimist ain’t I? :blush:

  1. I use the Johnson Control which worked very well and is easy to set up. If you search you will find many others ( see below for a sample)

  2. I suspend the probe in the lower third of the freezer hanging in the middle equidistant from the walls. Some people drill a hole in the side of the freezer and push it through. I don’t think that is necessary. I just hung it over the top and the lid closed tight enough. The probe’s wire is pretty thin… I would not drill.

  3. I bought some small “milk crate” storage cases. I would not put the fruit in sealed bags of any type. Keep in mind that a freezer chest is NOT “frost free” so it does not dehydrate the contents. I took a cereal bowl and put a wet Bounty paper towel in it to keep the humidity level up and as an easy test to see if the freezer was drying out. After three months the paper towel was still good and damp Some of the moisture will escape or freeze up onto the sidrs so the wet towel releases moisture as needed .I kept mine at 34-36 degrees and some of the moisture did freeze out onto the walls at the bottom. The wet paper towel kept the humidity level up enough so the fruit was not affected. NOT necessarily the “scientific method” to insure proper humidity but more like the “it makes sense to me” method . Easy humidity control & test.

  4. I would NOT let the produce touch the walls as the walls do get colder than the air as they absorb the heat to expel it.

NOTE : I will ( didn’t do it this year) add a small circulating fan to keep the air moving so as to equalize the temperature. I did get some freezing of the fruit on the bottom most layers of the boxes. Without the circulating fan, the bottom get much colder than the upper reaches.

Hope this helps



Yes, it does! A lot of great ideas! Thanks!

I’d be cautious about drilling a hole in the sides. Most chest freezers have their cooling coils running around the sides. It’s where the frost collects when you turn it on in freezer mode. You don’t want to hit those coils/tubes or the freezer is toast.

A safer bet is to run the temp sensor wire in thru the top edge when the lid is up, and duct tape it in place. The lid seal is usually flexible enough to handle the slight bump that will make.


I want tone day build a walk-in and use a cool bot.

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