The interesting thing about trying to garden with a little more intelligence than it previously required means that you find out fairly obvious things that really you should have thought about before.  Companion planting, it is suggested, helps other plants to grow with a little more vigour.  How this occurs is not always spelt out and probably has not been fully investigated.  We just have not really needed to know because we could slap on several nasty chemicals so that the plants could survive without the help of other plants.  Now that we cannot get lots of these chemicals we have to look at other methods of controlling pests and diseases in crop plants.  Companion planting must be a method of gardening that is ripe for serious research but in lieu of this there must be enough anecdotal evidence to convince people, that would like to garden with the help of nature, that there may be something here.  It costs nothing to a good grower except a few packets of seeds. 

If we accept that this could be a good way of growing, then it might bring with it other benefits.  We avoid the monoculture of growing the same plants close together.  Anyone in the
UK will tell you that their brassicas have been devastated this year with cabbage white butterfly caterpillars.  Maybe if I had put some companion plants between them, there would not have been such a problem.  What we are looking at is a more cottage garden type of planting system that allows flowers and vegetables to be interplanted. 

From my experience with tagetes this year I would suggest that there is a benefit to growing onions interspersed with it.  Grow the small French marigolds rather than the big African ones because some of the onions got a little shaded out this year.  So is this due to exudates from the roots of plants?  Is it due to their pungent smell?  Is there some other effect that might be coming into play?  I don’t know. 

If we are actively trying to improve the fauna and flora of the soil, a companion planting system may attract a more diverse range of organisms, which would encourage a more natural food chain.  If we add to this mychorrhizal fungi and allow an even more intimate soil community to develop then we may well achieve a more fertile response from the soil.  Using this fungus with green manures may also help to lock nutrients into the soil. 

The fragility of the mychorrhizal fungi is evident by their scarcity in our soils.  I sometimes see them around weed plants like dandelions but rarely anywhere else.  I am going to use dandelions as a companion plant next year. 

The comfrey plants on the allotment are going to be replanted during the winter and they will get a good dose of these fungi together with the moved rhubarb. 

A further advantage of using companion plants is that they attract insects that may predate garden pests.

To continue…

There are many sites that are really good at suggesting a variety of different plants for companion planting.  I have no idea if they work or not but I am going to check them out.  These plants are also good for introducing mychorrihizal fungi into the soil.  So if they are grown from seed in the greenhouse then pricked out with fungi, they can be planted in the garden next to vegetables or flowers. 

Possible advantages of companion planting.

• Plants that produce pest controlling chemicals either from their leaves or roots.  These could include tagetes and the herb plants.
• Plants that form a particularly good association with mychorrhizal fungi and will enable the fungi to form an association with crop plant roots. 
• Plants which have flowers that attract insect preditors such as hoverflies and lacewings. 
• Plants that could also act as annual or perenial green manures such as comfrey, nettle and sweet cicely and also do some of the above. 
• Plants that just make the allotment more attractive.   

I am going to list them here mainly as an aid memoir.

• Yarrow
• Monkshood (Aconitum)
• Bugle (Ajuga reptans)
• Borage - possibly with strawberries and pumpkins.
• Dill (Anethum gravellens) particularly with cabbage, lettuce and carrots.
• Chamomile (Anthemis) I grew this this year and will grow it again.  In some books it describes chamomile as the “doctor plant.”   Did well with my onions.  Also with cabbages.
• Chives around the base of fruit trees.
• Flax with carrots and potatoes.
• Hyssop with potatoes and grapes.
• Marogolds (Tagetes) It is really the main pest deterrent.  It suposedly keeps the soil free of nematodes, discourages many soil insects and looks quite good too. 
• Nasturtium with radish, cabbage, cucumber, fruit trees, and all the curbits.
• Petunia is good with beans.
• Rosemary is good with carrots, beans and cabbage.
• Columbine (Aquilegia)
• Pot Marigold (Calendula officinalis) Grew this this year and need to make sure that I give room to it.  It can shade out low growing vegetables.   
• Crocus.  I have just planted some in the allotment - without realising their potential.  They have been planted with mychorrhizal fungi.  I also planted grape hyasinth and snowdrops (Galanthus.)
• Californian Poppy (Eschscholzia californica)  This was planted and seemed to have an effect.  It is not a really long lasting plant and goes over very quickly. 
• Fennel (Foeniculum vulgare).  I don’t have any fennel at the moment but I might plant some next year. 
•  Hardy Geranium and Crainesbill.  I think I get these as weeds on the allotment. 
• Candytuft (Iberis) 
• Dead nettle (Lamium) with potatoes
• Lavender.   I grow this at home so it will not be a great problem to put them onto the allotment. 
• Poached-egg plant (Limnanthes douglasii) Now of all the companion planting this year, I think that this was the least sucessful.  It was planted under the apple tree but even so it could have made a better effort.  The upsetting and irritating thing is that it flowered for years alongside my allotment as an escape from one of the gardens.  Not on my allotment though. 
• Lobellia
• Honeysuckle
• Poppy (Papaver)
• Phacelia tanacetifolia
• Primulas
• Lungwort(Pulmonaria) This is growing alongside my allotment on the trackway. 
• Sedum
• Golden rod (Solidago)
• Periwinkle (Vinca) I have both the varigated and the wild one in my garden. 
• Dandilion is not usually included in the lists I have seen but I have dug up long taproots this year covered in mychorrhizal fungi.  
• Grass ?  I have just been weeding and a lot of the grass has mychorrhizal fungi growing on their roots. 

More information but without research evidence Tone:

http://juliesedwick.com/CPG1.aspx

 I don’t really mind if these plants do not have any affect on the vegetables in the allotment.  If I do interplant next year, they will brighten up the allotment a little.   

This entry was posted on Wednesday, October 8th, 2008 at 10:49 pm and is filed under companion planting, mychorrhizal fungi, allotment. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.