The soil willingly makes itself available to each seed. More often than not grows in the garden than we have sown. Pathogens that we have long forgotten can also survive in it. So that it doesn’t get that far, you can sterilize the soil and make it sterile. It is heated up and unwanted life potential is nipped in the bud. It still remains fertile and allows our seeds to grow well.
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Much can accumulate in the left to itself earth, which can damage our plants and in the worst case also destroy them. This also applies to the self-made compost, which is gladly and regularly distributed as fertilizer in the garden and put in the flower pots. For example:
- Viruses
- Fungal spores
- Insect owner
- unwanted weed seeds
Use hostile temperatures
Every life needs an optimal ambient temperature in order to be able to survive. This also applies to all life that the gardener does not want in his soil.
- there is an extended tolerance range
- beyond that, it becomes critical
- the simple cell structures are quickly destroyed
- even at temperatures around the 100 ° limit
- usually 30 minutes are enough
So if you want to get rid of the pests, you have to heat the earth so much and so long that it is destroyed. The disadvantage, however, is that the heat does not spare the beneficial soil organisms in the compost. Therefore, the benefits must be weighed carefully.
Sterilize the seed compost at home
The soil that benefits the most from the heat is certainly the seed soil. Or rather we are the ones who benefit because the sterilized soil allows our seeds to grow optimally. It no longer contains harmful germs that could pose a serious threat to the young plants. Since the sowing soil is usually required in smaller quantities, it can be made germ-free at home with the help of two household appliances:
- oven
- microwave
It does not matter whether you bought the seed compost in stores or mixed it yourself. Heat both of them for good results.
Free from germs in the oven
Always heat the potting soil just before use. If there are a few days between sterilization and sowing, store the cooled soil in an airtight place. So no unwanted germs can get into them.
- Preheat the oven to 200 ° C top and bottom heat.
2. Slightly moisten the potting soil.
3. Spread the potting soil flat in a fire-proof container.
4. Leave the container in the oven for 30 minutes at the same temperature.
5. Stir large amounts of soil in between.
6. Let the finished result cool down well before continuing with the sowing.
If the capacity of the container is not large enough, you can heat the desired amount in several passes.
Sterilize the soil in the microwave
When sterilizing in the microwave, heating for ten minutes is sufficient. Set the microwave to the highest level, which is usually 800 W. Here, too, you can make larger amounts of soil sterile in several successive runs.
Carry out the cress test beforehand
You cannot see with the naked eye how strongly any earth is “contaminated” with harmful germs, spores, seeds and the like. On the other hand, heating large quantities in a space-limited oven and microwave is a tedious job. The cress test can clearly show us when it is really important to sterilize soil and when it can be dispensed with.
- Fill a small saucepan with it
- look at it with cress seeds
Everything is fine only if the cress seeds germinate within three days and then develop healthy, white roots. Otherwise, soil should be made germ-free in the oven or microwave.
White dots are not a cause for panic
When the earth goes black in the oven or microwave and comes out again with white dots, the amazement is great. But there is a logical and understandable explanation for this. Inside were small worms or insect larvae, most of which consist of protein. The egg white has taken on a white color as a result of the action of heat and has only become visible through this. Earth with white dots is “harmless” and can be used without restriction. The worms and larvae certainly did not survive the heat.
Sterilize compost and large amounts of soil
Hard-working gardeners make their own compost from plant waste. The concern that unwanted germs could also be found in it awakens the desire to make it germ-free with heat to be on the safe side. That needs to be carefully considered:
- Compost is very much alive
- full to the brim with beneficial microorganisms
- these continue to work after the compost fertilizer has been applied
- with their work they improve the soil
If the decision to sterilize is not made, this is theoretically feasible with the devices described above. The capacity of an oven quickly reaches its limits here. For the sterilization of larger amounts of soil in the private sector, special earth dampers are available with which larger amounts of soil can be sterilized more easily.
Let third parties steam the compost
If you don’t sterilize soil too often, it may not be worth buying an earth steamer. Not only the cost-benefit ratio could play a role, the space for its storage is also a decisive argument.
Just ask a large local nursery if they can steam your compost for you. It can of course be the case that they ask for a contribution to the costs, but the bottom line is that it can be worthwhile.
Conclusion
Viruses, fungal spores, insect larvae, they all lurk in the garden soil and in the compost and wait to thwart our work. We can defend ourselves against this by heating the earth before use and thus rendering all undesirable germs harmless. This can also be done well at home.
