Compost is nutrient-rich and therefore ideal as growing soil. However, the soil from the composter often still contains fungal spores, bacteria and other pests that can be dangerous to seeds and young plants. One way to sterilize the substrate is to steam the compost.
How to steam compost?
Steaming compost is an effective method for producing germ-free potting soil. The compost soil is heated in the oven, microwave or steamer to kill germs, bacteria, weed seeds and pests. The steamed earth should then cool down thoroughly before being used.
Steaming compost for germ-free potting soil
Seedlings and young plants need nutritious but germ-free soil to really thrive. Of course, you can use potting soil (€6.00 at Amazon) from a hardware store. You can also make the substrate yourself by steaming the compost.
The compost soil is heated to kill germs, bacteria, weed seeds and pests.
Only steam as much soil as you actually need. The heating also kills many useful microorganisms. They don't play as big a role for young plants as they do for later plants that you want to fertilize with compost.
How to steam compost
There are three ways to steam compost:
- Oven
- Steamer
- Microwave
Pour the soil into a fireproof container. If it is very dry, spray it with water and then cover it with aluminum foil. Use the microwave for steaming, do not use aluminum foil, but use special containers.
Steaming compost in the oven
Set the oven to the desired temperature and steam the compost for about ten minutes.
Steaming in the microwave
The earth is heated at 600 watts for around ten minutes. The earth must steam.
Steaming in the pressure cooker
Fill the pot with water as directed and hang the container with the soil. Steaming takes place at high pressure for about 15 minutes.
What temperatures need to be reached when steaming?
The temperatures depend on what you want to use the soil for later. Most bacteria and germs are killed at around 70 degrees and ten minutes of steaming time.
For tomato and tobacco plants, you should steam the substrate at over 100 degrees. Under no circumstances should it get hotter than 200 degrees.
Tip
The steamed earth becomes very hot and retains heat for a long time. Allow them to cool thoroughly before handling and using them. Store unused substrate in a well-sealed plastic bag.
