Companion Pairing Checker

Choose any two crops above and this tool will tell you, instantly, whether we have a documented companion-planting relationship between them - beneficial, antagonist, or simply unrated if no specific relationship is recorded for that exact pair. Everything runs in your browser; nothing you select is sent anywhere.

Why This Exists

Most companion-planting charts online are static images or tables that only cover a fixed set of famous pairings and offer no way to check a combination that isn't already printed on the chart. This tool works the other way around: it reads the same structured relationship dataset that backs every written companion-pairing page on this site, so any pairing we've catalogued is checkable here directly, and any pairing we haven't catalogued is honestly reported as unrated rather than silently ignored.

How the Result Is Determined

The tool looks up your two selected crops against a curated set of real-demand companion relationships, each one tagged with a relationship type (beneficial or antagonist), a mechanism category (nitrogen fixing, pest masking, trap cropping, allelopathy, root-depth complementarity, physical support, shade sharing, pollinator attraction, living mulch, nutrient competition, or shared disease risk), and an evidence rating (evidence-backed, traditional lore, or mixed). If a full written page exists for the pair you selected, the tool links directly to it for the complete explanation; if the write-up isn't published yet, the tool still gives you the recorded relationship and evidence rating without linking to a page that doesn't exist.

What "Unrated" Actually Means

Most possible crop combinations are genuinely neutral - two crops can grow perfectly well next to each other without any documented beneficial or antagonist interaction at all. An unrated result from this tool means exactly that: we don't have a specific catalogued relationship for that pair, not that the pairing is secretly bad. If you're planning a bed with a crop that returns an unrated result against everything else on your list, that's not a red flag - check each individual crop's own growing guide, since a crop's confirmed companions and antagonists are always listed there even if a specific cross-reference against every other crop in your garden doesn't exist yet.

Beyond a Single Pair

This tool is built for checking one pair at a time. If you're laying out a whole bed with several crops and want them arranged to respect every relevant pairing at once, the Bed Layout Helper does that automatically from your bed dimensions and full crop list, reading the same underlying relationship data as this tool so the two can never disagree with each other.

A Worked Example

Select Tomatoes and Fennel and the tool will flag them as a documented antagonist pairing with an allelopathy-negative mechanism and an evidence-backed rating - fennel root exudates measurably suppress the growth of a number of neighboring plants, tomatoes included, which is one of the more solidly evidenced antagonist relationships in this entire reference. Select Tomatoes and Basil instead and you'll get a beneficial pairing with a mixed evidence rating, since the commonly cited flavor benefit doesn't hold up the way the pest-masking reasoning plausibly does.