Interactive lesson

Storage without electricity, step by step

Interactive lesson: why stores spoil, the three storage groups, cold and damp without a fridge, what must not share a room, preparation and safety in the cellar.

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This lesson is general guidance, not professional training. Local regulations and expert advice always take precedence. Read our disclaimer.

The whole lesson as text

1. Why stores spoil

A lifted potato, a carrot and a picked apple are still alive.

Produce breathes — It uses up sugar and starch and ages. That gives four reasons for spoiling: respiration, water loss, rot and frost.
Warmth speeds it up — For every 10 °C warmer, spoiling runs roughly 2–3 times faster. A carrot that keeps five months at 1 °C keeps a few days at 20 °C.
Water loss — Root vegetables are 85–90 % water. Once they lose 5–10 % of their weight they turn shrivelled and rubbery, even though they are not rotten.
Frost — Most vegetables and fruit freeze at around −1 °C (30 °F). After thawing they turn soft and rot.

Why: Once cut off from the plant they go on breathing: they use up sugar and starch and give off heat, water and CO₂. Slow their breathing with cold and hold their water with humidity, and they last for months.

A good store should smell of earth, not of mould. A sour or musty smell means rot somewhere or too little air.
Your nose is the first instrument, but it does not replace a thermometer.

2. The three storage groups

Not all winter stores can share one room.

Cold and damp — 0–4 °C (32–39 °F) and 85–95 % humidity: carrots, beetroot, celeriac, cabbage, apples, pears, quinces. Place: cellar, clamp, pit.
Potatoes a little warmer — Potatoes belong to the same group, but at 4–6 °C (39–43 °F). Do not keep them below 3 °C.
Onions cold and dry — Onions and garlic: 0–4 °C and 60–70 % humidity. In a damp cellar they sprout and rot. Place: a cold spare room, hallway, or the loft as long as it does not freeze.
Squash warm and dry — Pumpkins and winter squash: 10–15 °C (50–59 °F), 50–70 % humidity. Below 10 °C they suffer. Place: an unheated room, under the bed.

Why: Split them into three groups and find a place for each. Most want cold and damp, onions cold and dry, and squash warm and dry.

The conditions are approximate and apply to sound produce of late (maincrop) varieties.
In your first winter, measure the temperature in every possible spot in the house, then place your stores.