In a mixed culture, the influences of different plants have a positive effect on each other [Photo: Irina Fischer/ Shutterstock.com]
Mixed cropping was invented on farms in the early 19th century. Century. Because unlike what the "peasant garden" in many botanical gardens conveys to us, peasant gardens before the 20. In the nineteenth century, the crops were by no means neatly divided by box hedges, sorted according to aesthetic criteria and neatly tended. In fact, these were fields where crops for humans and animals grew together without separation, forming a diverse community of life. In this way, positive influences of the plants on each other were used and space, water and fertilizer were saved. Overall, the yield of the area was increased, while the expenses for the food and feed produced remained low. In return, such an area had to be cared for and maintained somewhat more intensively so that it did not run completely wild. Today, this type of cultivation is called "mixed cultivation" and can be found in organic cultivation guidelines, z.B. in Demeter cultivation, again. We introduce you to the mysterious world of mixed plantings.
What are the advantages of mixed crops?
No wonder that nature is also one mixed culture. Through competition and selection, highly efficient ecosystems develop in nature. If you take a look around in untouched nature, you will not discover any pure or monocultures. In fact, mixed cropping systems are teeming, because the more diverse a system, the better use can be made of every available resource. Introducing mixed crops into your own garden offers all kinds of advantages:
- The total yield per area increasesIn mixed cultures plants are planted next to each other, which have different demands. Thus, under a tall, sun-loving tomato (Solanum lycopersicum) a small and shade-tolerant lettuce (Lactuca sativa), making the best use of the space and the shade provided by the higher species favors the other one. Incidentally, this principle is also used in agroforestry systems. For example, sun-loving banana plants are grown among more shade-loving coffee plants. However, one should not only consider the above-ground form, but also the root. While some species are deeply rooted and thus draw their nutrients from deeper soil layers, others remain rather close to the surface. Planting them next to each other has the advantage that they do not compete with each other. The space can thus be optimally utilized in all directions.
- The susceptibility to pests is reduced: Mixed cultures are by far not limited to the space requirements and the demands of the plants, but also make use of plant defense strategies. Many plants have a particularly intense smell, for example cabbage (Brassica), rosemary (Rosmarinus officinalis) or sage (Salvia). These odors originate from substances in the plants that are supposed to repel pests and pathogens. Thus, essential oils of herbs are nothing more than plant defenses. If you now combine certain plants with each other, you can use this ingenious development of the plants. An effective combination here, for example, is tomato with basil (Ocimum basilicum) or strawberries (Fragaria) with garlic (Allium sativum) can be combined against mildew or even roses (Pink) with lavender (Lavandula) to reduce aphid infestation. In addition, mixed cultures attract pests less and encourage more beneficial insects through more diverse habitats.
- The vegetables taste better: In fact, when properly combined, the very additional ingredients that often serve as plant defenses can affect the taste of fruits. There is no general reason why this is so. What is certain, however, is that savory (Satureja) has a positive effect on the taste of common beans (Phaseolus vulgaris) when it grows underneath.
- Less fertilizer is neededBecause there is less bare soil in a closely planted mixed culture and it is also interspersed with a dense network of plant roots at different depths, fertilizer losses are much lower. Nutrients washed out downwards can be absorbed by deeper-lying roots. There is hardly any "outgassing" of nutrients, because those compounds that could volatilize are absorbed immediately. In addition, all plant species have different nutrient acquisition strategies. That is, they have different tactics for releasing nutrients from the soil and making them available. If plants with different tactics grow together, this also increases the fertilizer utilization. The reason for this is that each individual plant has, so to speak, a much larger arsenal of options available to it for dissolving nutrients from the soil.
- More biodiversity: A greater diversity of crops and better mixing not only benefit the plants themselves. Numerous animals also benefit from this, as it provides them with many more habitats and food sources.
- Improved soil activity: The new diversity of plants and therefore the increased diversity of plant residues will not provide the soil with a one-sided supply of organic material. What one-sided organic residues can result in extreme cases becomes clear in pure coniferous forests, where the soil becomes acidic due to the countless needles. In a mixed forest, on the other hand, accumulating needles are not a problem. The diverse remains balance each other out in their extremes. Not only does this have a positive effect from a chemical point of view, but it also increases the biodiversity of soil organisms, as more food sources are available. The increased three-dimensionality and density of the plants also makes better use of the space immediately on the ground, thus increasing ground cover. The result is that erosion is reduced and the soil remains moist, which also promotes soil life, resulting in higher soil fertility.
What to consider with mixed culture?
Since mixed crops are an incredibly complex system, because plants influence each other in a wide variety of ways – both positive and negative – the whole thing seems quite difficult to figure out at first. Fortunately, through centuries of experience, we humans have figured out which plants go best together. Planting tables are available for this purpose, showing how well one plant goes with another. Sticking to these will therefore give you a good opportunity to orient yourself. For the basic structure, the following can be said:
- The three-dimensional structure of the space was to be used to the best advantage, so tall and sun-loving species were to be combined with smaller and shade-tolerant ones. The same applies to the combination of deep-rooted and shallow-rooted species.
- Plants with an intense smell – such as various herbs, bulbous plants, but also, for example, tagetes (Tagetes) – usually have a deterrent effect on various pests and pathogens. These species can be combined with susceptible species.
The chosen combinations should be checked against the planting tables to eliminate possible incompatibilities between the plants.
Which plants go together?
Plants can affect each other both positively and negatively. We tell you which plants are mutually beneficial as plant neighbors and which you should rather not plant next to each other.
Some plants can protect neighboring plants from pests and pathogens by intensely smelling ingredients. In the following table, we have compiled some favorable combinations for your consideration.
|Aphids||General||Tagetes, garden cress, parsley, mint|
|Lettuce and cabbage||Chervil|
|Roses||Lavender and sage|
|Cabbage white butterfly||Cabbage||cut celery, sage, rosemary, thyme|
|Miscellaneous||Potatoes, cabbage, tomatoes, strawberries||Tagetes|
|Snails||Edge planting with hyssop, tansy, chervil|
|Bacteria and fungi||Garlic and other leeks||Strawberries, roses|
|Powdery mildew||Tomatoes, cucumbers, cabbage||Basil|
|Column rust||Currants and jostaberries||Wormwood|
|Monilia||Cherry and peach trees||Horseradish|
Good neighbors, bad neighbors
Which plants have positive effects on each other and which combinations have rather negative effects, you will find out in the following overview.
Expert Tip: Although less fertilizer is needed in mixed cultivation – as already explained – fertilization should not be completely dispensed with. The reason for this is that when vegetables are grown, many nutrients are removed from the soil. A high quality fertilizer such as Plantura Organic Universal Fertilizer is excellent for your bed.