Thank you for sharing! :)

This looks great, John, thanks!

John,

The area of 'why' is a wonderful addition but still ventures into the folklore perception. Most of the on-line charts show the why. There are a few sites that offer plants in answer to a problem. The latter sources are likely how you generated your chart and the effort is appreciated.

The companion plant relationships are one area of personal study. My goal is finding actual facts offering the biological, chemical and/or ecological contribution. Some of the obvious are know symbiotics.

I have posted a few links in Organic and Vegetable topics that have been looked at. It is very hard to locate specific relationship studies and suppose that there are few actual such studies.

One item of note is the marigold action against nematodes. In report I have view they credit the exudates but after residue is incorporated and decomposing. The effect is generally of advantage in the following year of the incorporation. Food for thought and example of the information I hope to provide in such a chart.

Good effort. Thanks.

Organicdan - it is good to see someone looking for real evidence in this area. So much of what people state is unbacked by research and seems largely anecdotal or hearsay. In fact much of it is downright silly. For example recommending as 'good for each other' plants which have completely different habits and requirements e.g. garlic and rhubarb. My rhubarb is an 18 year old clump over five feet across in damp shade. I don't think garlic would be too happy alongside. I am keen to learn which combinations actually work but there is so much nonsense talked that scepticism is my default position much of the time.