How to Build a $10 Underground Cooler for Year-Round Harvest Storage, by Hayden Walsh Food Storage on YouTube. 12 min 27 s.
- Video length
- 12 min 27 s
- Time to do it
- 4 hours
- Difficulty
- Medium
- Steps
- 9
What you need
Steps
Choose a shaded, well-drained spot that stays cool in summer and does not collect rainwater. Dig a hole wide enough to leave about 6 inches of soil around the container on every side.
Keep digging until the top of the container will sit below your local frost line. In most temperate regions that means 18 to 36 inches deep, so check your county frost depth chart first.
Add a 2 inch layer of gravel to the bottom for drainage, then lower the container in. Check the rim with a spirit level in both directions and pack soil firmly around the sides.
Spread a 2 inch cushion of dry leaves or straw in the base. Brush loose soil off your produce and let roots cure for a day or two before they go in.
Fill the container in alternating bands of produce and dry leaves, starting and ending with leaves. Keep each produce layer thin so air can still move between the items.
Put storage apples on top of the pile, never mixed in with the carrots. Apples give off ethylene gas that makes roots sprout and turn bitter.
Stop filling about 4 inches below the rim so the lid does not crush anything. Set the lid on and pile roughly a foot of dry leaves over the top.
Wrap the lid edge and any vents with quarter inch hardware cloth to keep mice out. Press the leaf mound down and weigh it with a board or a few bricks.
Check the store every 2 to 3 weeks. Pull out soft or mouldy items, add dry leaves if the inside feels damp, and top the mound back up after wind or snow.
Tips and common mistakes
Keep a thermometer in the store and aim for 32 to 40°F. Ground below the frost line sits near 50 to 55°F, so the leaf layers and lid insulation are what keep the swing small.
Dry leaves are the insulation. Wet leaves rot and let the cold through, so swap them out if they get damp.
Leave out anything that has to be truly frozen for safety, plus water-heavy crops like cucumbers, tomatoes and summer squash, which go to mush.
A foot of leaves on the lid is the step most people skip, and skipping it is what freezes a whole harvest.
Questions
How deep does the hole need to be?
Deep enough that the container top sits below your local frost line, usually 18 to 36 inches in temperate regions. Your county extension office can tell you the frost depth for your area.
What crops can go in the cooler?
Carrots, beets, turnips, parsnips, cabbage, potatoes kept in the dark, and storage apples. Keep apples on top and away from the roots.
Will my produce freeze in a cold snap?
The ground below the frost line holds a steady temperature and the leaf layers buffer sharp swings. Check with a thermometer after cold nights and add another foot of leaves if needed.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
