Companion Planting Research

I'm researching the practice of companion planting and I'd appreciate your input/answers to help me better understand this practice.  I've begun building a tool to help with companion planting planning, but want to have a more informed understanding from this group on the topic.  Answers to any/all of these questions or any other insights/wisdom would be appreciated.

1. What role does companion planting play in your yearly planting activities?  Do you see it as important in your planning activities?
1a. Do you consider C.P. once you've picked out what you want to grow to optimize placement?
1b. Do you consider C.P. to consider additional annuals you'd like to incorporate into your garden?

2. Is C.P. pretty limited in application to just personal/home growers, or is it applied in commercial/larger scale growing as well?

3. It seems to me that C.P. is focused on annuals, and you're looking at Guilds when you approach perennial/permanent plant planning.  Both are related to the practice of employing polycultures with objective of improving growing outcomes.  Is this accurate?

4. How do you source your C.P. wisdom?  I've seen various charts/grids from various locations.  Even Wikipedia has a substantial amount of relationships defined for C.P., with sources/citations on some of their C.P. info.  How do you know what is legit, and what is unproven/anecdotal?  Do you trust some sources more than others?

5. Do you have specific objectives/categories of benefits in mind when considering C.P.?  What are they?  eg, insect repellent, general benefits, etc?

6. What resources/tools do you use to assist in C.P.?

Thanks everyone!

Hi Jeremy. Welcome to Permies.

1) I companion plant guilds of annuals that support primary and secondary crops, and act as such themselves. One example with which I usually have great success is the interplanting of tomatoes with basil and oregano. Not only do the herbs act as scent distraction for pests looking for tomatoes, they also go well in tomato sauce. I like to add at least one type of allium in close proximity, and marigolds on the perimeter of every block.

I tend to not only plan out guild plantings of annuals, but their succession throughout the season as well. If there is a convenient slot into which I can drop another compatible crop of annuals, I like to do so, yes, and I do tend to keep in mind the specific mechanics by which companion planting works.

2) This thread addresses that question, and I have supplied the link that is the subject of the thread as evidence of companion planting informing planting decisions in a commercial setting.



3) Whatever the lifespan of the organism involved, the ideas remain the same. If I were to grow tomatoes in a 4-season hothouse in which tomato vines were a perennial, the details might change, but the reasons for my choices and the theories behind them would remain constant. Scent distraction, sacrificial trap-crops, predatory insect support, none of the issues or the tools we use to address them change.

4) I started mining the internet for my companion planting knowledge, and happened upon Wikipedia's List of Companion Plants, on which I still rely as a rough guide. Other than that, I like to keep a seasonal log, and if I have an idea, I test it out and observe. I try to use my mind to analyse whether or not the claims made make sense in light of species-specific data that I use to correlate datapoints.

For instance, if all sorts of claims are being made about, say, the nitrogen-fixing bacteria-hosting capabilities of buckwheat, I like to look at articles and studies that focus on that particular trait of buckwheat.

Also, keeping track of why the specific plants are supposed to offer the benefits that are being ascribed to them can be helpful. That way, you can place the scent distractors in the right place with regards to the normal prevailing wind, and the pollinator-drawing species that rely on dozens of visually stunning clusters of tiny flowers filled with bee and butterfly food can also be appropriately located.

5) The specific objectives and categories of benefits and their priority in my planning depends largely on what problems exist with the site. If I have a need for predatory wasps because of some pest species they like to prey upon, that will probably come first. If the site lacks pollinators, or if my neighbour plants a lot of a single crop that draws an excess of one particular kind of pest, such that normal control methods are overwhelmed, I might accordingly either focus upon pollinator shelter and habitat, or I might actively avoid plants in the group that my neighbour is growing, so that there's no draw to my gardens for those pests.

6) On a commercial scale, with interplanted crops, mapping locations and tracking time to maturity is key, and planning such that annuals to be harvested are matched to be harvested in the same range, or so that early crops act as nurse crops before their harvest to compatible companions that mature through the flowering stage to produce a crop.

Keeping a data log, or a biotime log, can help with time and space management, and with the recording of time, input, and yield data. I like excel for this, as you can graph the data.

Good avenue for research. We need all the hard data we can. Keep us posted, and good luck.

-CK

Thanks Chris, this is great info.  Lots to dig into.  I appreciate hearing your perspective.  It would be great to hear if others have a different take on any of these questions.

You mention the major categories of benefits/value in C.P. as the following:

1) Scent distraction
2) Sacrificial trap-crops
3) Predatory insect support

You also mention nitrogen-fixing bacteria-hosting capabilities of buckwheat, and nurse crops, and even food parings (tomatoes/basil/oregano).  Maybe that's 4,5,6, but I typically look at those as a different category than C.P..  I'm not sure why.  I'll have to do some introspection there.  :)

Are there other dimensions for C.P. as well?  Pollinator attraction?  Anything soil/below-ground to consider?  Any symbiosis other than nitrogen fixing?  

The timing aspect is interesting as well, especially re: nurse crops.

Thanks again.

Here is a handy chart.

Three sisters.

When I was a new gardener, or actually when I had only a little experience and was spending a lot of time fantasising about future gardens, then I read a lot about companion planting. I'm not a hugely experienced gardener but have now had a small personal garden for 15 years, and have helped in some bigger gardens. Once I got underway, I found that other considerations ended up taking precedence, such as where there is space to tuck something in between something else that will be finished in time, or when I finally got hold of those seeds I'd been wanting. Other gardeners will find other considerations compelling them to grow certain things together, like maybe they share a trellis or a soil or sun need, or things along the fence have to be those few that are unpalatable to the grazing animal nearby, or any of 100 other reasons.

Now I have come to believe that what is most important is just to have a diverse ecosystem, and it matters less exactly what is next to what. Of course black walnuts and maybe other walnuts are actually alelopathic, but very few of the other reputed alelopathic plants turn out to really be a noticeable problem, in my (limited) experience and googling. Diversity is incredibly helpful for many different reasons, including soil development, healthy ecosystems leading to pest control, hedging bets in case of any one crop failing, and more.

Nowadays my garden-reading urges tend more towards information about temperature and timing, or varieties that might solve certain problems I've had.