Cool in summer and warm in winter
Crater beds are little secret weapons in the climate garden. They store heat and moisture and protect sensitive plants from winds. Thanks to these special properties, they ensure that plants thrive better. Vegetables in particular benefit from this. We show what a crater bed can do and how it is built.
Crater beds are still quite unknown in our regions. In areas that regularly experience long dry periods in summer and lots of downpours in winter, people have long been relying on the crater-shaped beds to garden successfully despite difficult weather conditions. In America and Canada, too, some gardeners have already tried hard and can achieve good results. Since the weather tends to reach extremes due to climate change, a crater bed can also be a good alternative to conventional beds in our gardens.
Advantages of the crater bed
Crater beds are particularly beneficial for growing vegetables. The advantage of the crater bed is that plants that are sensitive to frost can also be used. With a cover in spring, the crater bed can also be used as a cold frame and late frosts have little effect on the sensitive plants. In addition, the temperature inside the crater is higher when it is cold than outside and when it is very hot, the temperature inside the crater is lower than outside due to evaporation.
A crater bed is divided into several zones. Through these different zones, the crater bed meets the different requirements of the different plants, because each zone has a different degree of soil moisture and different levels of solar radiation. Vegetables and herbs can be grown here in mixed culture (linked to mixed culture page). Since planning a mixed culture is already a bit of a challenge, and now the sun and water factor are added, you shouldn’t be too demanding in the first year and try something out first. Mistakes are allowed and teach the correct handling of the crater bed and the correct planting.
Cross section with plants
The zones: which plants for which area?
In the middle of the crater, the ground is moist and there is little wind movement. The water therefore collects and can either seep away or be collected in a small pond. This has the advantage that more water is available for the plants that are grown. The small pond and the more humid soil also create evaporative cooling in summer and heat storage in winter. Temperature fluctuations are compensated.
Alternatively, the bottom of the crater can be laid out with stones. These store the sun’s heat throughout the day and release it at night. This variant is suitable in areas with many days of frost and it extends the season.
In this zone, frost-sensitive and heat-loving plants can be grown, which do not mind a higher level of humidity. There is also space for tall plants. You get enough water, while the tall shoots can dry off with a little air movement. Tomatoes and peppers can grow well here. Edible aquatic plants can be grown in a small pond.
The slopes of the crater are drier, the drought increases towards the top. Warmth-loving plants that like to have dry feet are in good hands here. The slope of the bed has a shadier and a sunnier side. The northern side of the crater is always sunny due to the path of the sun.
So that the slope is not washed down by the rain, it can be terraced with stones and thus secured. In the course of the season this is done by the roots of the plants. If soil is washed from the slope into the crater, the slope is too steep and should be touched up again. When creating the crater, it can simply be left unplanted for the next rain, so you can see whether the earth is slipping and, if necessary, make improvements. Especially the downwind side of the slope is calm. Plants can grow here that have a moderate need for water, do not like it too frosty and cannot tolerate strong sun, such as salads.
Whether vegetable plants or ornamental plants: everyone decides what goes into the crater bed, of course. Vegetables or herbs can be grown in the form of a mixed culture. Local perennials can also be planted, so you can do something for insects and birds. Tomatoes, peppers, aubergines, French beans or the sensitive aloe vera can also be grown in cooler locations in Germany. Like cucumbers, zucchini, basil, celery and strawberries, they are sensitive to frost. This can occur at the beginning and at the end of the season. The warmth in the crater bed can soften these frosts and thus extend the season. Tomatoes, cucumbers and aubergines also need a little more water, especially at the beginning of cultivation. Therefore, the location inside the crater is ideal for them.
The slopes are well suited for vegetables with average demands. Radishes, parsley and strawberries can grow here. French beans, lamb’s lettuce, onions and carrots can also be grown well in these transitional areas. They also tolerate somewhat drier soil. The wall is the driest area and is therefore also suitable for herbs such as sage, thyme, origanum and lavender. In addition, this area is particularly suitable for native wild perennials. Mallow, chicory, adder’s head, meadow sage, catnip, wild carrot, horn clover and other survivors magically attract insects and make the crater bed a hot spot for biodiversity. Upholstered soapwort, cranesbill, and gundermann also look beautiful and form decorative carpets around the crater.
Trees can be planted behind the wall that can tolerate drought. So something can be harvested even in hot years.
Sea buckthorn, rock pear, and sloe are also useful for insects and birds. Wild roses look beautiful and after flowering they have rose hips, which birds are very fond of. As a post-crop in late summer and autumn, lamb’s lettuce or phacelia are suitable. So the ground is protected over the winter.
This is how a crater bed is built:
Step by step:
- 1. Find a suitable location (sunny, at least two meters in diameter).
- 2. Put a piece of wood or a stake in the ground to which a one meter long cord is attached.
- 3. Now mark a circle with a radius of one meter.
- 4. Dig the soil in a cone shape within the circle. The deepest point should be 20 centimeters below ground level.
- 5. Mix the excavated material with humus.
- 6. Apply the excavated humus mixture around the crater and on its slopes. The northern side can be built higher. The wall should be 20 to 30 centimeters high.
- 7. Now a small staircase should be built at the southern end of the crater. There is a stepping stone in the middle of the crater. A small pond can also be used here if there is enough space.
- 8. Now comes the slide test: Either wait for the next rain or water the crater with a garden hose. Is the earth sliding down? Then the wall is too steep and it has to be improved, the slope must be flattened.
- 9. If everything is firm and secure, the plants can be planted and watered.
- On the north side, tall shrubs or trees can be planted as wind protection.