With a cold frame, the windowsill is finally freed from countless seed containers for growing plants. You can build the practical box yourself in the garden and use it in early spring to grow ornamental and useful plants. The right filling ensures pleasant warmth without electricity. Find out how to do it here.
How do I fill a cold frame correctly?
To properly fill a cold frame, you need horse manure with bedding, humus-rich garden soil, compost and horn shavings. First place vole wire (€15.00 on Amazon) and a layer of leaves or straw in a 50 cm deep pit, then 20 cm of horse manure and on top of that 20 cm of soil-compost mixture. Annual replacement of the filling is required.
Preparing the warming filling – this is how it works
The special advantage of a cold frame is the natural development of heat. Seeds can germinate and young plants can thrive here when there is still snow in the garden. The natural heating results from the following filling:
- Horse manure with a third of straw or leaf litter
- Humose garden soil, enriched with mature compost and horn shavings
Horse manure has the task of developing heat as a result of its decomposition. This rises into the compost soil to vitalize the soil organisms there. Seedlings and young plants benefit from this interaction because they already thrive when the garden is still in deep winter dormancy.
Filling the cold frame – how to do it right
Place the prepared fillings within easy reach at the designated location for the cold frame. How to proceed step by step:
- Dig a 50 cm deep pit
- Line the bottom of the pit with fine-meshed vole wire (€15.00 on Amazon)
- Lay a layer of leaves or straw on top
Fill the horse manure on the base to a height of 20 cm. This is followed by the prepared mixture of garden soil and compost, which also forms a 20 cm thick layer. If you don't want to take the soil from other parts of the garden, you can of course use the excavated soil for filling.
Renew filling every year
The contents of the cold frame only fulfill its function as a natural heat source for one season. To reap the benefits next year, dig up the filling in the fall and fill the pit with fresh horse manure in the spring. You can use the decomposed organic material to provide nutrients in ornamental and kitchen gardens.
Tip
Give the filled cold frame a week to develop sufficient heat under the closed cover. Only then can you sow seeds or plant the plant in the ground. Please note that the filling must be replaced every year so that the natural heating works.
