Why Your Tomatoes Won't Ripen

GardenDraft Team · July 28, 2026 · 5 min read

Part of: Plant Problems & Pest Guides

It's a familiar late-summer standoff: the tomato plant is loaded with big, full-size fruit, and every one of them is stubbornly green. Nothing's wrong with the plant. When tomatoes won't ripen, it's usually because ripening takes longer than people expect, and a few specific things can stall it further. Here's why it happens and how to nudge it along.

Why tomatoes won't ripen: it takes longer than you think

From the moment a tomato reaches full size, it still needs a couple of weeks or more to color up: green to ripe isn't fast. So the first answer is often simply patience. But two conditions genuinely put the brakes on:

• Heat. This surprises people: tomatoes actually stop producing their red pigment above about 85–90°F. In a heat wave, ripening pauses, and fruit can sit full-size and green (or stuck at an orange blush) for as long as the heat lasts, resuming only when it cools. So a hot spell, not a problem with the plant, is frequently the culprit.
• Too much foliage and fruit. A plant carrying an enormous load of fruit, or buried in dense leaves, spreads its energy thin and ripens slowly.

How to speed it up

• Stop feeding nitrogen. Late-season nitrogen pushes new leafy growth at the expense of ripening. Ease off and let the plant shift its focus to the fruit it has.
• Prune and reduce the load. Thinning some foliage lets light and warmth reach the fruit, and removing tiny late-formed tomatoes that won't finish concentrates energy on the ones that will — this is part of pruning tomatoes.
• Top the plant late in the season. A few weeks before your first frost, cut off the growing tips and any new flowers. The plant quits trying to make fruit that can't finish and pours everything into ripening what's on the vine.
• Ease back on water slightly as fruit matures — a touch of stress can prompt ripening (without going so far as to cause cracking or blossom end rot).

When frost is coming, ripen them indoors

Here's the key fact that saves the end-of-season crop: a tomato does not need to ripen on the vine. Once a fruit has started to turn — even showing the faintest blush, or just reaching the mature "mature green" stage — it will ripen perfectly on a counter. So before the first frost ends the season, pick all the full-size fruit and bring it inside. Set them stem-up at room temperature (not in a cold fridge, which kills the flavor and stops ripening), and they'll color up over the following days and weeks. A paper bag with a ripe apple or banana speeds it along, since the ethylene gas they give off triggers ripening. You'll be eating your own tomatoes weeks after the garden has frozen.