The basic principle of mixed cropping is to create plant communities based on nature, whose synergistic effects are beneficial for plant and soil health. To defend and protect themselves, plants produce chemical messengers called phytoncides. The emission of the messengers serves to inhibit the growth of other plants competing for light or nutrients and to repel pests. Phytoncides can have a positive or negative effect on other plants. This interaction among each other is called allelopathy. For example, if one plant emits scents that attract certain pests, but the neighboring plant releases scents that distract the pests, mass spread is not as easy.

Since when has there been mixed cropping?

In the classic cottage garden vegetables are planted together with flowers. Here, mixed cropping has a long tradition. Hans Molisch has written down approaches to mixed cropping already 1937 in his work „The Influence of One Plant on Another-Allelopathy“. However, only with Gertrud Franck in the 1940s, mixed cropping was taken to a new level. Marrying farmer Hannfried Franck in 1935, Gertrud became an estate wife. On her estate in Baden-Württemberg, she planted a 1-acre vegetable and fruit garden, which also became the site of her mixed cropping experiments. The basis of the experiments were Gertrud’s observations that some plants thrive better in certain neighborhoods. Gertrud developed her own row-mix culture system that took into account interrelationships and compatibility among vegetable, fruit, herb, and ornamental varieties. Her concern was to provide rural women with a viable and energy-efficient horticultural system that they could use for self-sufficiency. From her decades of observations and experiments, she developed lists of plants which were mutually beneficial and which were not. In 1957-1965, the „Soil and Health News Journal“ published a series of articles on Gertrud’s mixed-cropping system. With the German version of her book „Companion Planting: Successful Gardening the Organic Way“, she shared her knowledge with the public in 1980.

Probleme der Monokultur

"A country that destroys its soils, destroys itself."

Franklin D. Roosevelt

In agriculture, the standard is monoculture. In monoculture, farmers can acquire good specialized knowledge, they do not need a great deal of machinery, and they can market the products profitably in large quantities. However, land farmed in monoculture is quickly depleted by the one-sided cultivation and the many (mineral) fertilizer treatments. This promotes soil erosion, i.e. erosion of the soil by wind and rain. Soil erosion is already leading to crop losses on 70 % of agricultural land in developing and emerging countries. A 2015 study shows that 33 % of the world’s arable land has been lost over the past 40 years due to overgrazing and intensive farming, among other factors! According to the Food and Agriculture Organization, about 90 % of soils could become unusable for agricultural use by 2050! Mixed cropping could be a possible solution to prevent this.

Is mixed cropping sustainable?

In arable farming, mixed cropping still plays a subordinate role. Reason for this is the still poor research on the fundamentals and applications of mixed cropping. Studies are complicated by the fact that countless factors (e.g. soil, weather, care) influence the results. In a long-term Nature study conducted as part of the EU project „DIVERSify“ in 2021, the research group led by ETH professor Christian Schöb demonstrated that mixed cropping in arable farming produces higher yields than monoculture. At their trial site in Zurich, they already obtained 21 % more seed yield with a two-species grain mixture. The plants were more vigorous and suffered from less pest pressure.

According to Prof. Schöb, mixed cropping has great potential in agriculture. However, more studies are needed, and it is necessary to invest in training and advisory services for farmers, optimize seeds and provide technical aids.

Mixed cropping plan - When choosing neighboring plants, pay attention to:

„Cruciferous plants“: Plant family that includes cabbage, leafy vegetables such as pak choi, Asian lettuce, and arugula, as well as radishes, radishes, and cress.

Advantages of mixed cropping

Plus the advantages of a permanent ground cover (mulch):

But:

Mixed cropping needs to be well planned and requires extensive research and knowledge about which plants go together, when to sow and harvest, and much more. But, don’t worry, we will help you plan! Just let us know what your needs and preferences are, and we will provide you with an optimized mixed cropping plan!

Common mixed cropping practices - Cultivation plan

Mischkultur Hochbeet Pflanzplant - Mischkultur Gemüse Tabelle

These plants have a beneficial effect (due to essential oils):

Basil

e.g. for cucumber, cabbage

  • Keeps whiteflies and mildew under control
  • Improves aroma

Dill

e.g. for carrot, lettuce

  • Promotes seed germination
  • Keeps pests away

Coriander

e.g. for potato

  • Improves aroma

Marigold

e.g. for cabbage, tomato

  • Protects against nematodes
  • Repels whiteflies and aphids
  • Loosens soil
  • With flowers attracts bees for pollination

Calendula

e.g. for leek, potato

  • Protects against nematodes
  • Keeps slugs away
  • Loosens soil
  • With flowers attracts bees for pollination

Chamomile

e.g. for celery, strawberry

  • Promotes resistance against fungal diseases
  • Improves aroma
  • With flowers attracts bees for pollination

Bean

e.g. for tomato

  • Brings in symbiosis with nodule bacteria nitrogen from the air into a plant-available form

Onion/ Garlic/ Leek

e.g. for tomato, strawberry

  • Promotes resistance against fungal diseases
  • Repels whiteflies and aphids
  • Keeps slugs away

These pairs of plants have a positive mutual effect:

Carrot & Leek/Onion

  • Carrot repels onion fly
  • Leek/onion repels carrot fly

Celery & Cabbage

  • Celery keeps away cabbage pests
  • Cabbage protects against celery rust

Pea & Lettuce

  • Lettuce grows much faster and can be harvested before the peas start gaining growth momentum 

In any case, these plants should not be planted together in the mixed cropping plan:

Also be careful not to put bad neighbors next to each other, as they emit acids and gases that hinder neighboring plants! They also attract the same pests and diseases.

Cruciferous plants

Do not grow cruciferous plants together, especially if they remain on the bed for a long time! Cruciferous plants are particularly sensitive to pest infestation.

Solanaceae

Solanaceous plants are often affected by late blight, the pathogens of which are spread through the air. Therefore, tomatoes and potatoes, for example, should also not be placed in the direction of the wind to each other.

„Solanaceae“: Plant family that includes tomatoes, potatoes peppers, and chilies.

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