People often request that we suggest companions. This isn't something we would define in the system, it's something we'd want to get from members' data. Personally, I'd also like to encourage people to specify why something works well as a companion, because what works in some climates/soils/environments might not work in others, or people might want to find stuff that makes practical sense (eg. root depth, pest repellent, shade) vs companion pairings that are mostly mystical in nature.

Suggested:

• When you add a planting, you can specify a companion from a dropdown list of other plantings in that garden
• You can also give a description/notes on the companion relationship, eg. "beans provide shade for lettuces in hot weather"
• We can show a summary of companions on the crop detail page, eg. "African marigold (33), garlic (23), basil (21)" and if you click through you see details of the notes people have added about the companion relationship.