Steaming soil from compost: instructions

The soil in the garden is contaminated with viruses, fungi or bacteria, the compost should be germ-free or potting soil is required for new plants. Here it is helpful to warm up the compost used accordingly and to kill off everything harmful that is in it. Buying an earth steamer is not cheap and often not necessary if only a small amount of material is to be dampened. But there are other types and one or the other self-made earth damper, if this does not have to be used constantly.

Steam compost, why?

Compost soil is used as a fertilizer to help the plants grow well and produce a lot of yields. If it is mixed under the earth, it should therefore germ-free so as not to infect the garden soil with bacteria, fungi, pests or viruses. Because during composting, all possible plant parts from the garden come together, which could also be covered with fungal spores or bacteria. Pests, on the other hand, such as white grubs, are spread by the beetles that lay their eggs here in the compost heap. If the fertilizer is then mixed into the garden soil in the beds, the plants can quickly be threatened with extinction. These pathogens can be killed by moist heat, heating the soil and the compost to around 80 ° C in connection with moisture in the form of steam is sufficient here. There are the following possibilities to build earth dampers or to use other devices for this, which are also not expensive:

• Grill and aluminum pot
• Use the microwave (for small quantities)
• Use the oven (also small quantities)
• Steel barrel or barrel with lid

Note: A commercially available earth steamer, for example a steam wheelbarrow, consists of a wheelbarrow with a built-in electric steam generator, grate, thermometer, filter and lid. However, these devices are very expensive with a purchase price of 1,600.00 euros.

Grill and aluminum pot

If you don't want to steam large amounts of compost every day, then buying an earth steamer from a specialist retailer is usually too expensive and does not pay off. Should a little compost be steamed under the garden soil before mixing it in, then the conventional grill is suitable for this, irrespective of whether it is electric, gas or coal or a corresponding one Pot. The instructions for self-construction are very simple and can be quickly dismantled and stowed away afterwards. The following materials are required for the barbecue earth damper:

• grill
• Gas bottle, socket or coal
• Aluminum pot with lid
• matching steam insert
• cloth
• possibly thermometer

For example, the large steam juicers, which already consist of four parts, are suitable for the aluminum pot. The water is poured into the bottom pot, the steam escapes via the collecting pot for the juice, the compost to be steamed is in the top pot and the lid is placed on top. The old canning pots, which usually even have a thermometer in the lid, are also suitable.

tip: It used to be common to use a saucepan to extract juice. Often these old pots are still in the grandparents' basement, you could also find something here for little money at a flea market or an Internet second-hand goods site.

Instructions for self-construction

If you want to build the earth damper yourself, you should follow these instructions for building it yourself. If the above-mentioned materials have been procured, the earth damper can be assembled as follows:

• Fill the lower part of the aluminum pot with water
• Place a cloth on the steamer rack
• then comes the compost
• can be slightly moistened
• loosely place the lid on the pot
• Plug in the thermometer
• put everything on the heated grill

Once the pot has warmed up to 80 ° Celsius according to the inserted thermometer, it remains on the grill for about 30 minutes. However, if the temperature rises significantly, the lid should be lifted in between. Because at higher temperatures, the nutrients in the compost can also be damaged.

tip: As an alternative to the grill, if you don't have one, you can also heat the pot on a stove and put it under steam.

microwave

The microwave is only suitable for very small portions, but it also does its job well as an earth steamer. The steam time can also be shorter with the microwave. When using the microwave for sterilization, you can proceed as follows:

• Use a microwaveable bowl
• Do not use them in the kitchen later
• Fill in the desired, small amount of compost soil
• moisten them well
• Give up the lid
• Steam for ten minutes on the highest setting
• let cool down well

tip: The advantage of steaming the soil is that it is in the compost Release trace elements and nutrients immediately and not after a few weeks, so these the plants immediately benefit.

oven

The oven is also suitable for sterilizing small amounts of composted soil, for example if you only want to fill individual pots or a balcony box. To do this, proceed as follows:

• Fireproof bowl that is no longer needed in the kitchen
• Fill about ten centimeters high
• Lay the aluminum foil loosely over it
• alternatively pierce a few holes
• Steam must be able to reach the earth
• Fill the drip tray with enough water
• Set the oven to 80 ° C
• Note the heating time
• then leave in the oven for 30 minutes
• Turn off the oven, open it and let it cool down

Note: If the smell bothers you, you can also use a roasting tube into which you pour the soil. Then you have to moisten the composted soil well beforehand, otherwise there will be no germicidal steam in the well-sealed hose.

Steel barrel or barrel with lid

The advantage of the steel barrel is its size, because it allows a large amount of compost to be sterilized at once. In order to use the steel barrel on a fire pit, you need to take safety precautions:

• looking for a safe place
• no trees or bushes in the immediate vicinity
• Put stones on the ground
• Build a small wall of stones all around
• The fire can burn safely in this fireplace
• use a sturdy grid as a cover
• later the heavy bin will stand on it

tip: If the fireplace is securely set up, it can be used for steaming the compost but also for other purposes at any time. So you can build seats around the place and sit comfortably by the campfire in the evening.

Steaming in a steel barrel

When it comes to steaming the compost in the steel bin, you should always work in pairs. Because the bin alone is already heavy and you have to put it on the grate on the fireplace. After that, you can fill in the soil. The advantage here is the large amount that can be sterilized in a single process. You have to moisten the filled soil with a hose beforehand. Then proceed as follows:

• ignite a fire
• Put the lid on the bin
• Plug in the thermometer
• If the temperature becomes too high, remove the cover
• so steam can be released
• leave for 30 minutes from a temperature of 80 ° C
• then put out the fire
• Let the earth cool down
• then remove from the bin and recycle

As a thermometer, a boiling thermometer can also be used here, which is large enough to put in the top of the bin. Alternatively, you can drill a sufficiently large hole in the lid into which the thermometer can be inserted.

Note: So-called thermal composters are also available in stores. However, these are not recommended for disinfecting the soil. Because the steam required for this cannot form here due to the lack of ventilation slots and therefore With this composter, the clippings decompose faster, but bacteria, pests, viruses and fungi remain available.