Creating a cold frame - instructions for the perfect structure

Creating a cold frame - instructions for the perfect structure

Simple functionality - different model variants

The cold frame works like a miniature greenhouse. So that seedlings and plants can flourish here from February / March, sun rays and a special filling ensure sufficient warmth, which is held in place by a movable cover. Those who only rely on the sun's rays as a heat source can use side panels and covers made of transparent material, such as double wall sheets. If you integrate natural heating into the structure, the side parts can be made of wood. The following models are suitable for cold frames:

  • Wooden frame with disused windows as a cover
  • Frame and cover made of glass or plastic
  • Aluminum box with plastic lid
  • Cold frame tunnel made of weatherproof, transparent film

also read

  • How to build a cold frame from pallets - DIY instructions
  • How to properly fill a cold frame - instructions for practitioners
  • How to build the cover for a cold frame yourself

If you correctly lay out your cold frame in a box shape, use a model with a slight incline towards the south. This means that your plants can still benefit from the light even when the sun is low. In addition, rain runs off more quickly. For good ventilation it is important that you can open the lid. Currentless ventilation openers automatically provide fresh air when a certain temperature level is exceeded.

Flexible dimensions - you should pay attention to this with the width

The structure of a cold frame depends on the dimensions of the space available. The more space is available, the longer the box or foil tunnel (€ 9.92 on Amazon *) can be. The width, however, should be limited to a maximum of 100 cm so that you can easily reach all plants from the edge.

The heart of the structure - filling as natural heating

A cold frame functions as a cold box when the sun is the only source of heat. By integrating an ingenious filling as natural heating into the structure, you can optimize your cold frame into a warm frame with an extra long service life for up to 365 days. Before setting up the frame structure in the garden, prepare the location as follows:

  • Dig a 50 cm deep pit in the sunny location
  • Line the sole with vole wire and a 5-10 cm thick layer of leaves
  • Fill in a 20 cm thick layer of horse manure
  • Put a 20 cm thick layer of garden soil, compost, green cuttings and horn meal on top

The decomposition process of the filling generates a heat of 18 to 22 degrees Celsius in the tightly closed cold frame within 8 to 10 days. These are the ideal conditions for sowing and planting while it is still bitterly cold outdoors.


Upcycling of Euro pallets (€ 16.99 at Amazon *) is very popular in order to conjure up furniture or flower boxes (€ 13.19 at Amazon *). Resourceful home gardeners simply build a cold frame themselves from old or new pallets. With a little manual skill, the wooden transport documents are converted and provided with a transparent cover.