Creating a Mixed Culture in Your Garden

Here's what's ahead:

• What does "mixed culture" mean, exactly?

• Botanicals: natures's pest repellant

• Simple mixed cultures to try

• Mixed cultures in a raised bed

• Mixed cultures with perennial plants

What does "mixed culture" mean exactly?

In a mixed culture, different plants are grown side by side at the same time, which offers a number of advantages:

• The available space is used more efficiently (height, width and depth of your bed)

• Dense planting keeps moisture in the soil and helps avoid weeds

• Certain plants benefit each other (e.g. pest defence through fragrances)

• Light, water and nutrients are more ideally and naturally distributed

As with crop rotation, it is also important in mixed cultures to ensure that members of a plant family are not cultivated directly next to each other, since diseases and pests can spread more easily within families.

You should also alternate deep and shallow roots, since deep roots can access nutrients and water from deeper soil layers. On the other hand, you should not combine fast-growing plants with slow-growing plants, as the ones that grow taller faster will take up more light and food than the stragglers.

It would be ideal to mix heavy, medium and weak consumers in one bed. The difficulty here: If you want to create a colourful mixed culture, it becomes very complicated to also stick to a proper crop rotation, both in terms of nutrient requirements and plant families.

But there is a simple trick you can use to do this: In your mixed culture, focus on planting plants with similar nutrient requirements in the same bed. This will allow you to keep track of your crop rotation and create space for a colourful mix of different plant families when planning the bed.

Some examples:

Year 1: Mainly heavy feeders (cruciferous: cauliflower, cucurbit: zucchini, umbellifer: carrot)

Year 2: Mainly middle feeders (Foxtail family: beetroot, nightshade family: eggplant, leek family: onion, umbellifers: oat root)

Year 3: Mainly weak feeders (lepidoptera: peas, composites: lamb's lettuce)

Year 4: cover crops (various flowers)

Botanicals: Nature's pest repellant

Sufficient space, water and nutrients are usually safe in a colourful mixed culture, but a perfect plant partnership is not only based on appearance and basic needs. So what does a plant look for in order to find its soulmate?

The key is a word you’ve probably never heard before: Phytoncides!

Now this doesn't sound particularly romantic, but it is very relevant for you as a gardener, if you are looking for good partners or neighbours for your plantbabies.

Phytoncides are odorous or liquid excretions that plants use to have a positive or negative effect on other plants. These include, for example, saponins. Saponins ("substances that foam like soap") have a growth-promoting effect on recurring cultures. Plants that secrete these substances are, for example, spinach, orache, potato, beetroot, tomato, primrose, pansy, globe flower, peony and delphinium.

In symbiosis with nodule bacteria, papilionaceae bind nitrogen in the soil, and also secrete a substance called heteroauxin, which promotes root growth, particularly in fruit trees. Like we said…romantic. We dig it.

Flowers such as marigolds promote plant health and boost your plant's version of an immune system. These planty pheromones kill rootlets, small animals in the soil that prefer to eat roots.

Many herbs have a positive effect on vegetable plants with their essential oils:

• They improve taste: New potatoes taste better with thyme and coriander, carrots with dill, radishes with cress.

• They ward off pests: Cut celery protects cabbage crops from flea beetles and caterpillars; Thyme, sage and peppermint protect your cabbage plants from the cabbage white butterfly and its voracious caterpillars; Along with beans, savory acts as a shield against lice; Basil, nasturtium and garden cress protect tomatoes from black psylla.

• They promote growth: Dill allows carrots, onions, peas and cucumbers to thrive better, chervil will help your salad grow.

• They attract pollinating insects: Borage is a natural matchmaker between insects and cucumbers or zucchini.

Unfortunately, the world of plant compounds remains very under-explored, and it is largely up to us gardeners to discover new worlds of favourable bed partnerships. Ahoy!

Simple mixed cultures to try

Now there are some very established and popular mixed cultures that we want to share with you. These are some that you can easily try out, even as a garden newbie:

• Cabbage and lettuce: The lettuce keeps flea beetles away from the cabbage.

• Carrots and onions or leeks: The conflicting scents of these plants confuse invading pests as they approach. It is best to combine early carrots with onions and late carrots with leeks. Late carrots and onions do not go well together, because carrots need a lot of water in late summer to prevent them from bursting, while the onions should be dry on the bed during this time.

• Tomatoes and basil: Not only do they go great together in an Italian-style dish, but both like it moist. The tomatoes protect the basil and the soil around it from drying out, whereas the basil keeps aphids away from the tomatoes with its scent.

• Corn, beans, and squash – also known as the "Three Sisters": This hybrid culture was practiced by the Maya and Aztecs centuries ago. The corn serves as a climbing aid for the beans, which in turn enrich the soil with nitrogen for the other two heavy-eaters. Serving as a ground cover, the pumpkin suppresses weeds and retains moisture in the soil. Its fruits only ripen in the autumn sun after the beans and corn have already been harvested. Corn and squash should be planted or pre-planted a few weeks before the beans in spring.

• Cucumbers and dill: The John and Paul of your mixed bed. The cucumbers keep the soil moist, whereas the dill keeps pests away and encourages growth. And after harvest, this dream team will harmonise perfectly in your salad. All you need is looooove…in your garden…

Mixed cultures in a raised bed

Now if you are growing in a raised bed, you are probably going to end up with a mixed culture on a de-facto basis, since everything has to be placed next to each other in such a small space. For permanently high yields, you should also ensure that you provide a “good neighbourhood” and sufficient crop rotation.

If you are creating a new raised bed, you can plant heavy and medium feeders such as peppers, broccoli, cucumbers and lettuce in the fresh and nutrient-rich humus soil. Remember to mix different plant families. In the second year then, you can then sow seeds from other plant families such as carrots and beetroot. For example, you can usually plant lettuce several times in a row without any problems. As always, be careful with your cabbage. Don't plant white and red cabbage, cauliflower, broccoli, kohlrabi, radishes, rocket, mustard, etc too close together, and be sure to avoid letting them follow each other.

If you notice any disease or pest infestation, you should take a break from raised bed gardening to sort out the infestation, and make a note not to grow members of the same plant family for a few years. Mould spores and the larvae of many pests overwinter in the soil and will return to your bed with a vengeance in the following year, so don’t assume that pests leave with your plants! Alternatively, you can swap out your soil to keep out new aerial invaders with dense crop protection nets.

Mixed cultures with perennial plants

In a mixed culture, it makes sense to also grow perennial plants. These are better adapted to their location, sometimes allow multiple harvests, are easier to care for, and are able to reach deeper nutrient reservoirs with their roots. Some plants also like to self-seed and remain in the same location for many years. Others only form flowers, fruits or seeds in the second year and will therefore stick around longer in your bed…just like you on a lazy Saturday morning. Here you have to adapt the mixed culture accordingly and only choose those annuals and perennials as bed neighbours that get along well with each other.

In the case of perennial plants that require a lot of nutrients, such as rhubarb or asparagus, you can plant beans, marigolds or phacelia in a mixed culture to provide them with sufficient nutrients and keep pests away. However, after a maximum of seven years of cultivation, you should allow your soil to recover from the perennial heavy feeders for a few years and only plant light and medium feeders during this time.

So let’s get cracking!

So that's Mixed Culture 101! Don’t forget to let us know in the comments below what YOUR experience has been with mixed cultures! What have your successes or “learning experiences” been? Remember, plants are fun, and trying new things is the best way to get to know our beautiful plant-friends even better.

So as always, have fun and happy gardening!