Horse manure in the cold frame is the ideal heating for growing vegetables. The bacteria in horse manure generate heat, which helps the plants.
Horse manure is considered the best "heating material" for the cold frame, because bacteria develop heat as the manure breaks down. This warmth helps to grow vegetable plants early in the year. Horse manure is available in packs from any garden center or garden wholesaler.
1. Dig and cover the pit
But first a 50 cm deep pit has to be dug. The cold frame should have a south-facing glass cover to take advantage of the heat. If the front of the bed is a little lower, the bed will be heated even when the sun is flat. So that no voles are up to mischief in the bed, it is necessary to tension a fine wire mesh on the bottom and the sides.
2. Fill the cold frame with straw and horse manure
The bed is now filled with approx. 10 centimeters of straw, which then has to be trampled down. This is followed by a 30 centimeter high layer of horse manure. This should also be tamped down well so that the remaining 20 centimeters of compost soil fit on it.
The fermentation of the horse manure creates a temperature of approx. 15 to 20 degrees; the best temperature to plant vegetables. However, you have to wait a week until the small biotope has enough warmth.