Not only do delicious cakes succeed in the oven, the heat there is also good for the potting soil if it is infested with pests and germs. Heat treatment in the oven is a simple method to prevent the infestation of fungi, larvae, etc.
Potting soil can be heated in the oven to 200°C and made germ-free
Potting soil from the discounter or from your own compost
Both variants are feasible, although using your own compost involves a little more work, since this soil also has to be sieved.
Both soils should be free of weed seeds, larvae, mold and pathogens to give seeds and young plants a good start. All these "soil additives" are not visible to the human eye and one might think that an expensive or self-produced potting soil would be optimal.
Most of the time this is not the case. Germs, fungi, etc., cannot withstand much heat and should die off in the compost container during hot rotting (60 to 80 degrees). Unfortunately, such high temperatures are not reached in private compost.
Make potting soil sterile in the oven
Heat treatment in the oven is a good way to combat plant-damaging soil organisms. Always carry out the treatment just before using the soil. If you decide to stock up, store the sterile soil in an airtight bag to keep it sterile.
- First, heat the oven to 200°C.
- Pour some water over the soil, but not so much that it drips.
- Place the potting soil in a fireproof container or spread it out flat on a tray.
- Place the tray/container in the oven for 30 minutes.
- Larger quantities should be stirred once.
- The sterilized soil must cool down well before it is used.
- If you need a larger amount of soil, you should sterilize several portions.
Optimum temperatures for pest control
Very high temperatures in the oven are not always necessary. Most viruses are already killed at 90 degrees, fungi are already destroyed at 70 degrees. Most insects and their larvae do not survive 60 degrees.
If you sterilize your soil in the oven at 70 degrees for about 30 minutes, most weeds, fungi and pests should be killed.