Mixed cropping and crop rotation have proven their worth in agriculture since the Middle Ages. You can also use these principles in your vegetable garden to create optimal growing conditions for your vegetables.
Why should you consider crop rotation and mixed cropping when growing vegetables?
Different vegetables require different and different amounts of nutrients. In turn, they also release different metabolites into the soil. Therefore, there should be a regular change between different plant species, a crop rotation.
If you always grow the same type of plant on the same area, what often happens is that monocultures are criticized: You stress the soil in a very one-sided way. Eventually, it will suffer from a lack of nutrients and the plants will also become more susceptible to pests and diseases. Alternating planting, on the other hand, favors nutrient exchange. In addition, different plants root through the soil to different depths and intensities, improving soil aeration.
Therefore, it is not only sensible but even necessary that you do not plant the same species every year, but alternate between crops. Otherwise, your crop yields will decrease over the years because the soil will eventually become depleted and will no longer be able to provide your plants with optimal nutrients.
By the way, this principle has been known since the Middle Ages. Even back then, farmers developed strategies for vegetable cultivation in which they grew the various crops in rotation on three fields: The so-called three-field farming.
The difference between crop rotation and mixed cropping
There are several options for rotating different crops:
- You can grow your crops in a specific crop rotation. Crop rotation means that you plant different crops one after the other within one season. For example, you start early in the spring with a pre-crop, followed by your main crop as soon as you have harvested the pre-crop. Often you can even plant a second crop. You can often bridge the waiting period until the next crop grows with an intercrop.
- Crop rotation is probably the most common method of cultivation: Crops that rotate every season are referred to as crop rotation. This means that in the first year you grow the first type of plant, then a second in the next, and so on. This involves alternating between weak feeders, medium feeders, strong feeders and green manure.
- A third option is mixed cropping, where several crops grow simultaneously on the same area.
- Note: Often the terms crop rotation and crop rotation are not neatly distinguished. Therefore, sometimes when crop rotation is mentioned, it actually means crop rotation.
Green manure, weak growers, medium growers & strong growers in crop rotation
With crop rotation, you rotate the plants you grow each year. A cycle lasts four years – NABU has summarized it in a clear graphic (see above). You usually always start with a high-yielding plant, i.e. a plant with high nutrient requirements. In the next year, you plant a medium crop, and in the year after that, a low crop. In the fourth year, you let only one green manure grow on your planting area. You can also do the cycle the other way around, starting with a green manure crop and ending with the strong eaters.
Which plants belong to the strong, medium and weak eaters differs in part depending on the source. Cucumbers and carrots, for example, are sometimes counted as strong eaters and sometimes as medium eaters. The same applies to beet and spinach.
According to Bio-Gärtner and Mein Schöner Garten, the strong eaters include, for example:
- Various types of cabbage
Suitable as medium growers are:
- Swiss chard
You can grow the following plants as weak growers:
- Many herbs
- Lamb’s lettuce
In the fourth year, green manuring takes place. It has many important functions for the soil: with their roots, green manure plants loosen the soil again, they ensure that nutrients such as nitrogen accumulate in the soil again and are often also a good food source for bees. The most popular plants for green manuring include, for example:
- Red clover
- Bee lover
You then work the plant remains of the green manure into the soil either in the fall or in the spring when they have died. This allows them to decompose into humus afterwards. Some green manure plants are also hardy. This means that they do not die over the winter and form a protective layer against soil erosion during the cold months. They can then be worked into the soil in the spring. You can also leave plants that are not winter-hardy on the surface until spring: The dead plant remains also form a protective layer on the soil.
Planting in crop rotation
A major advantage of crop rotation is that the soil is covered most of the year. This protects it from drying out and soil erosion. The principle is similar to that of crop rotation in many respects: For example, after a high-yielding crop such as potatoes, you plant a low-yielding crop such as lettuce.
In addition to the nutrient requirements of the individual plants, the season plays a decisive role in crop rotation: The growing season in our latitudes usually lasts from April to November. Therefore, you start with a pre-crop – Bio-Gärtner.de recommends lettuce or spinach, for example. Cucumbers, tomatoes or celery, for example, can then be used as the main crop. Spinach, lamb’s lettuce, lettuce or autumn beets are suitable as a second crop.
Even if a crop is not yet completely harvested, you can already start sowing the next crop. This is the ideal way to use the time. Intermediate periods can often be bridged with intercrops of radish, cress or lettuce. Intercrops sometimes also have the positive side effect of preventing or at least reducing weed growth.
Especially with your main crop, make sure that there are at least three years in between until the next cultivation, so that the soil also has a chance to regenerate and is not depleted unilaterally.
To make your vegetable garden a green success and to succeed in crop rotation, here are a few more tips:
- It’s best to keep a growing plan. In it, you note down exactly what you planted on which beds in which year and plan in advance what you want to plant there next year. That way you won’t lose track of what you’ve planted.
- Mixed culture and crop rotation can also be combined well: You can plant different plants in the same area in the same year and the same combination the next year one bed further. In this way, you ensure an even more balanced use of your soil.
- As a basic rule, plants in the same plant family usually have similar nutrient needs. You should therefore never grow them in the same area in two consecutive years.
- You must also pay attention to the right site conditions when growing in rotation: In particular, soil type, sun and temperature play an important role in determining which plants you can and cannot grow.
- Cultivation with crop rotation has another advantage: it makes fertilization almost superfluous. It is usually enough to apply fresh compost to your planting area at the beginning of your planting season. More fertilizer is not necessary.