Freshly harvested tomatoes, peppers and aubergine in a home vegetable garden
Vegetables

Fruiting Vegetables

Vegetables/Fruiting Vegetables

The headline surprise in this category: sweet pepper and chilli pepper are commonly the same species, Capsicum annuum, and genuinely cross-pollinate if grown near each other -- the same shape of relationship the Alliums hub describes for onion, shallot and spring onion. Tomato, aubergine and pepper/chilli all share the nightshade family (Solanaceae), but different genera and species there don't cross the way pepper and chilli do. Cucumber and squash share a family too (Cucurbitaceae) but are different genera and don't cross with each other either. The extended crops here add two more genuine stories: tomatillo and ground cherry are the same genus but, unusually, tomatillo actually needs a second plant nearby to fruit at all -- and sweet corn is literally the same species as this site's flour maize, the first cross-pollination pairing on this whole site that reaches across two different hubs.

Tomato Guide available
Pepper / Capsicum Guide available
Chilli Pepper Guide available
Aubergine / Eggplant Guide available
Cucumber Guide available
Winter Squash / Pumpkin Guide available
Tomatillo Guide available
Ground Cherry Guide available
Bitter Melon Guide available
Luffa / Ridge Gourd Guide available
Sweet Corn Guide available
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Sweet pepper and chilli pepper will cross-pollinate with each other -- they're commonly the same species. Both are typically Capsicum annuum, so any flowering chilli nearby will cross with sweet pepper grown for seed, and vice versa. If you're growing both for seed in the same year, treat them as genuine cross-partners needing real isolation -- not just two different-tasting crops that happen to look related.
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Sweet corn genuinely cross-pollinates with this site's flour maize -- they're the same species. Both are Zea mays, wind-pollinated, and crossing between them can even dull sweet corn's flavour the same season it happens, not just in seed saved for later. Growing both means real planning, not a background worry -- see the sweet corn and flour maize guides for the full picture.
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Most of this category needs real heat and a long season. Aubergine, greenhouse tomato, bitter melon and luffa in particular need protection in anything but a genuinely warm zone -- each crop's own page covers exactly where that line falls, and where it doesn't matter.