cold frame

horticulture

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Last updated

June 24, 2026

Quick Summary

A cold frame is a simple horticultural structure used to protect plants and seedlings outdoors. It is typically a low, enclosed bed covered with a removable glass or plastic sash.12

The primary function of a cold frame is to create a microclimate that is warmer than the surrounding environment. Sunlight passes through the transparent cover, warming the soil directly. At night, the cover traps the heat that has built up, preventing it from escaping and allowing the soil to release its warmth gradually, thus protecting the plants from cold temperatures and frost. This allows gardeners to start plants earlier in the season or grow plants that might not otherwise survive the local climate. When supplemental heat is added, these structures are known as hotbeds.23

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horticulture
Structures
Cold frames, used to start plants before the normal growing season, are low enclosed beds covered with a removable sash of glass or plastic. Radiant energy passes through the transparent top and warms the soil directly. Heat, however, as long-wave radiation, is prevented from leaving…
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Cold frames, used to start plants before the normal growing season, are low enclosed beds covered with a removable sash of glass or plastic. Radiant energy passes through the transparent top and warms the soil directly. Heat, however, as long-wave radiation, is prevented from leaving…
Read More