With a cold frame, everything is in the green in the garden. Equipped with natural heating, young plants thrive here when there is still snow outside, or there is snow again. Reason enough for the home gardener to finally buy the magic box. These building instructions explain how to build your own cold frame out of wood.

Old windows are ideal as a cover for the cold frame

Material and tools - a list for bargain hunters

To add a cold frame to your garden, you can dig deep into your pocket and purchase a pre-assembled kit. It's cheaper and has a lot of fun if you get hold of wood and accessories from suitable sources and assemble them step by step according to these building instructions. This materials and tools list lists all the important components:

  • 1 or more disused windows with wooden frames (from a recycling center, flea market or demolition company)
  • 8 wooden boards at least 20 mm thick (ideally spruce, larch, Douglas fir or oak)
  • 4 squared timbers
  • Wood preservative with a brush (product with the 'Blue Angel' environmental label)
  • hinges
  • nails or screws
  • Hammer, saw, screwdriver, ruler, spirit level

Instead of installing wooden windows, you can also create the cover yourself. This can be achieved, for example, with round rods made of 6 mm spring steel or brackets for foil tunnels (€11.46) and weatherproof greenhouse film. (€15.90) At the end of these assembly instructions you can read how to proceed professionally with the assembly of this unbreakable alternative.

How to build a wooden cold frame - step-by-step instructions

In the first step, saw the wooden boards to size. Match the length of 4 boards to the length and width of the window covering. Paint the cut slats and the window frames with an ecological wood preservative to protect the construction from rot. How to proceed:

  • Cut the 4 boards for the front and back to a height of 35 cm at the front and 50 cm at the back
  • Cut the two upper slats of the side walls to match the gradient from the rear wall to the front wall
  • Screw the side walls, front and rear walls together to form a box using the squared timber
  • Attach the window or windows with hinges to the rear wall so that the cover opens upwards

The gradient from the back wall to the front wall makes an important contribution to the functioning of a cold frame. The oblique orientation optimizes the light yield, which is essential for planting, especially in spring and autumn. It is important to ensure that there are no gaps in the construction, so that the wind does not whistle around the floral ears of your plants.

Which dimension is practical?

For effortless care work without contortions, we recommend a maximum depth of 100 cm. In this way you can easily reach every plant from the edge. With a length of 200 cm, your cold frame has an area of 2 square meters, which is perfectly adequate for starting with lettuce, carrots and radishes.

Build a cold frame cover yourself - this is how it works

Can't find old windows, are new windows too expensive, or are you concerned about the risk of breakage? Then you can also build the cover for your cold frame yourself. Instead of using glass windows made of wood, use round bars made of spring steel or the brackets for a foil tunnel. This has the advantage that you can flexibly adjust the height to the desired planting. For example, tomatoes can also be grown in the cold frame.

Brackets for foil tunnels have the advantage that they already have loops for attaching a weatherproof greenhouse foil. The aluminum rods are stuck into the ground and the foil is pulled over them. Rubber mounts provide the necessary stability.

Choosing and preparing a location - How to do it right

A well-planned choice of location and correct soil preparation contribute significantly to the efficiency of a wooden cold frame. In order for seedlings and young plants to thrive here even in adverse weather conditions, the stand in the garden should be sunny and protected. Due to the sloping shape, the plants make optimal use of even the smallest amounts of light. Natural heating provides the necessary warmth. How to properly set up a cold frame:

  • Dig a 40 to 50 cm deep pit in a sunny, warm spot in the garden
  • Fill horse manure with straw bedding up to a height of 20 cm
  • Alternatively, use cow manure with straw or leaves
  • Put a 20 cm layer of garden soil and compost on top

The large crowd of busy soil creatures immediately gets to work and decomposes the nitrogen-rich horse manure. Within a week, this process develops a pleasant warmth that rises to the surface. Seeds sown and young plants used can thrive in the shelter of the cold frame while the garden is still in deep hibernation.

tips

The wooden cold frame is not only the ideal cultivation area for sowing, cultivating and planting. The protected framework conditions are perfect for hardening plants that have overwintered or been grown on the windowsill. For the purpose of acclimatization, small plants remain in the cold frame for 10 days, so that the drastic temperature change from the house to the garden is cushioned.

Category:

Garden design