If you want to make your own potting soil from compost, you should steam the soil before use. This largely removes weed seeds and pathogens, as well as unwanted pests in the soil.
How can I steam homemade potting soil?
To steam homemade potting soil from compost, heat it in the oven at 90 degrees for 30 minutes, in the microwave at 600 watts or in a pressure cooker. Steaming kills weed seeds, pests and pathogens.
Make your own potting soil
Potting soil can be made yourself if you have a compost container. The compost contains plenty of water, few nutrients and the pH value is acceptable, in principle exactly the right composition. Since there is usually no “hot rotting” in the conventional compost box, that is, there are no temperatures between 60 and 80 degrees reached, remain in the earth
- Weed seeds
- Larvae and eggs of soil pests
- unwanted bacteria and viruses
- Mushroom spores
- Nematodes
Why steam soil?
When steaming the earth, hot steam is used. This successfully kills germs, fungi, etc. However, only as much soil should be sterilized as is currently needed.
Temperatures during steaming
Depending on which pests are to be controlled, the steaming temperature and time change. Viruses, for example, are killed at around 90 degrees, and fungal spores lose their ability to germinate at 70 degrees. Eggs and larvae of insects do not survive at 55 degrees. So steaming for half an hour at 90 degrees should remove most pests etc.
Three sterilization options
Potting soil can be sterilized in various ways.
In the oven
The oven is well suited for sterilizing potting soil.
- Preheat the oven to 100 degrees.
- Take a deep baking tray and line it with baking paper..
- Spread the soil on top.
- Moisten the soil a little.
- Cover everything with aluminum foil.
- Steam the soil for 30 minutes.
- Let them cool thoroughly before using.
If you do not use the soil immediately, seal it airtight in a bag. This means no new germs can penetrate.
In the microwave
Here you can sterilize small amounts of soil in a short time. The moist soil is heated in the microwave for 10 minutes at 600 watts.
In the pressure cooker
Soil in shallow bowls (preferably grill bowls), covered with aluminum foil, is placed in the steaming attachment of the cooking pot. Now water goes into the pot, then the steamer attachment. The pot is closed with the lid. If the water boils, the valve can be closed, creating pressure. The soil is steamed for 15 minutes. After it has cooled completely, the pot can be opened.
