Companion planting

I am sure most gardeners have heard about "companion planting" and it makes sense, to think about different combinations of plants.

So before you get planting, it is worth while to check how the crops are arranged. There can be good and beneficial neighbour hoods, or neutral but some combinations are bad and neither crop will florish.

There are a number or reasons, why good companion planting make sense.  

A   to protect from certain pests

B   to provide shelter

C   to  release certain nutrients  

These combinations are not always symbiotic or mutually beneficial and sometimes there is just one crop which benefits the neighbourhood of the other but not  necessarily the other way round.

Well known combinations are carrots and leeks. In that case the leeks (it also could be onions) are deterring the carrot fly and the carrot the onion fly through releasing a scent not attractive to the pest.

Another combination in the garden are roses and lavender, It just doesn't look good, but the lavender is protecting the roses from green flies.

Strong smelling Herbs are often beneficial because they release a scent which is not attractive to certain pests or sometimes they influence the taste (caraway,coriander with early potatoes) 

(caraway,coriander with early potatoes)

IF you plant a few tomatoes between your cabbages, the chances that the cabbage white butterflies go to your neighbour to lay the eggs. (dill,sage, thyme and leaf celery work also) are a lot bigger. In that case, you "sacrifice" the tomatoe for the benefit of the cabbage

Garlic is another good plant to plant between other crops as it is good to prevent fungi and  bacteria.  

 You also can use other plants to protect more sensitive plants. For example grow runner beans to protect cucumbers or grow any tall growing plant to provide some shade (salads, spinach)

Grow plants with big leaves to protect the soil(like a layer of mulch) For example grow spinach between rows of potatoes, or grow courgette between sweet corn to cover the otherwise bare soil. Courgette, sweet corn and  climbing beans are a good combination.

Other plants release certain  chemicals below the surface (like Tagetes/French marigold deter some nematodes) and others (beans/peas, lupins or clover) collect nitrogen which are needed by brassicas. 

Combinations to avoid are

Salad/lettuce next to parsley
Dwarf beans next to onions
Potatoes next tomatoes
Cabbage next to onions
Tomatoes next to peas  

Good companions are

dwarf beans next to cucumber, potatoes, brassicas, beetroot,salads and tomatoes
carrots        next to leek, garlic, onion, rosemary, sage,dill,  tomatoes, peas
courgette     next to sweet corn, climbing beans, nasturtiums, beet root
potatoes      next to spinach, caraway, nasturtium,chamomille,mint, tagetes