By Jagdish Reddy | 10+ Years Gardening Experience
Research Sources: University of Missouri Extension • Purdue University’s Yard and Garden program
Updated: August 2026
Why Are My Tomatoes Not Turning Red? Tomatoes usually fail to turn red because temperatures are too hot or too cold, the fruit has not reached the mature green stage, the variety ripens to a different color, or growing conditions are slowing the process. In good conditions, mature green tomatoes typically start changing color within days and finish ripening over the following 1 to 3 weeks.
How Does a Tomato Actually Turn Red?
Tomatoes can keep ripening after they are picked, unlike fruit such as citrus that only ripens on the plant. That is the whole reason picking green tomatoes and finishing them indoors works at all.
Ripening starts when the plant releases ethylene gas inside the fruit. That hormone triggers chlorophyll, the pigment behind the green color, to break down. As chlorophyll fades, lycopene and other pigments become more visible, changing the fruit from green toward red.
Temperature strongly affects how quickly that process moves. Around 68 to 77°F, ripening generally proceeds steadily. Temperatures outside that range can slow the process, which explains several of the reasons below.
Quick Diagnostic: What’s Actually Going On
Before troubleshooting, check these five things. Those five details usually point to the cause, and they take less time to check than reading through all 15 reasons below:
- How big is the fruit, and does it give slightly when pressed?
- What color is it right now, dark green, pale green, or blushing?
- What have daytime highs been for the last two weeks?
- What have nighttime lows been?
- What variety is it, and how many days to maturity does the packet list?
Firm and dark green with no blush usually means “not there yet.” Pale green with a faint blush and recent heat above 90°F usually means “waiting on cooler weather.” Full size, pale, and nights below 50°F usually means “waiting on warmer weather.”
15 Reasons Your Tomatoes Are Not Turning Red
| Reason | What’s Happening | Fix |
|---|---|---|
| Short heat wave | A few hot days pause color change temporarily | Wait it out, no action needed |
| Sustained heat | Weeks of heat can break down pigment already formed | Pick at breaker stage, finish indoors |
| Cool nights | Ripening enzymes work slowly below about 50°F | Wait, or ripen indoors near 65 to 70°F |
| Not mature yet | Fruit hasn’t reached mature green internally | Leave on the vine, recheck weekly |
| Late-maturing variety | Some cultivars list 80 to 100 days to maturity | Check the seed packet, be patient |
| Excess nitrogen | Favors leaf growth over fruit ripening | Correct only if fertilizing heavily, not routine |
| Foliage over the fruit | Local shade and poor airflow at that cluster | Light pruning near ripening fruit |
| Poor airflow around plants | Traps heat and humidity across the whole row | Space at 24 to 36 inches next planting |
| Heavy fruit load | Energy is split across many tomatoes at once | Usually resolves on its own, no action needed |
| Inconsistent watering | Adds stress alongside other factors | Water on a set schedule |
| Hot-cold day swings | Repeated swings disrupt a steady ripening pace | Mulch to buffer soil temperature |
| Uneven ripening on one fruit | Shaded side of that fruit lags briefly | Normal, evens out within days |
| Off-red variety | Genetics set a yellow, orange, or striped finish | Confirm variety, not a defect |
| Season ending | Falling temperatures and shorter days slow it | Harvest mature green before frost |
| Still early | Ripening takes 1 to 3 weeks even in good weather | Recheck in a week |
1. A short heat wave
A handful of days above 85°F usually just pauses the color change rather than harming the fruit. The tomato stays firm and green during this stretch, which can worry gardeners expecting steady progress. Once temperatures ease back down, ripening picks back up where it left off.
2. Sustained heat over several weeks
Prolonged heat is different from a passing wave. During prolonged heat, a tomato that has started blushing may develop less red color or appear to fade toward yellow-orange as lycopene development is disrupted, especially across two or more weeks of daytime highs above 90°F. University of Missouri Extension notes that roughly a third of a tomato’s lycopene sits in the skin, which is the part most exposed to sustained heat. If this pattern shows up repeatedly in your climate, picking at breaker stage and finishing indoors tends to give more consistent results than waiting it out.
3. Cool nights early or late in the season
Ripening enzymes slow considerably once nights sit below roughly 50°F for several nights in a row. This shows up most in early spring plantings and again as fall approaches, and it is a timing issue rather than damage to the plant. Fruit in this situation usually still ripens fine once nights warm back up, or it can be brought indoors if a longer cold stretch is expected.
4. The fruit hasn’t reached mature green
Full size is not the signal gardeners often assume it is. A tomato has to complete internal seed and gel development, called the mature green stage, before color change can start at all, regardless of how large it looks from outside. A gentle press test and a check for any lightening at the blossom end are more reliable indicators than size alone.
5. The variety simply ripens late
Large beefsteaks and many heirlooms are listed at 80 to 100 days to maturity, while cherry types often finish in 55 to 65. Green tomatoes not turning red is often just a mismatch between a long-season variety and a short growing window. Checking the packet or catalog listing before assuming a problem with the plant itself can save weeks of unnecessary worry.
6. Too much nitrogen
This matters only if you have been fertilizing heavily with a high-nitrogen product after flowering began. Signs include a plant that looks lush and leafy but has set relatively little fruit for its size. It is not a reason to add fertilizer if you have not been feeding heavily. Plants growing in average garden soil rarely need correcting here at all.
7. Foliage directly over the ripening fruit
This is a local issue at one cluster, not the whole plant. Dense leaves right above a fruit trap humidity and block airflow to that specific tomato, which can lag it behind others on the same vine that happen to get more light and movement around them. Snipping just the leaves shading that cluster, rather than a heavy overall prune, is usually enough.
8. Poor airflow around the plants
This is a whole-planting issue rather than a single-cluster one. Rows planted too close trap heat and humidity across the bed, which compounds any heat-related delay for every plant in that row rather than just one fruit. It is more of a next-season fix than something to correct mid-summer, since moving established plants usually does more harm than good.
9. A heavy fruit load
A plant carrying dozens of tomatoes at once divides its resources thinner, so each fruit can take a bit longer to reach full color than it would on a lighter plant. This usually sorts itself out as earlier fruit ripens and gets picked, easing the load naturally without any pruning or thinning required.
10. Inconsistent watering
Letting the soil dry out and then soaking it heavily adds stress on top of whatever else is going on with the plant. It rarely causes green fruit by itself, but it is worth ruling out alongside temperature, especially in containers, which dry out faster and swing between extremes more than in-ground beds.
11. Repeated hot-cold day swings
Steady heat or steady cold at least gives the plant a consistent condition to work through. Big daily swings, hot afternoons followed by cold nights, can slow the ripening process further, since the fruit never settles into one steady state long enough to make progress. A layer of mulch that buffers soil temperature can take some of the edge off, even though it won’t fix the swings entirely.
12. Uneven ripening on the same fruit
The side of an individual fruit facing the sun often colors first, leaving the shaded side pale for a few extra days. It looks uneven but is not a defect, and it usually evens out on its own within a few days as the whole fruit finishes ripening together.
13. A variety that never turns red
Yellow, orange, and bicolor heirlooms reach their own ripe color and stop there, sometimes with a slight blush at the shoulders but nothing close to full red. That is genetics, not a growing problem, so it is worth confirming the variety on the tag or seed packet before troubleshooting further.
14. The growing season is ending
Cooler fall temperatures and shorter days slow the whole process down together, not just one part of it. This is the point to start picking mature green fruit ahead of frost rather than waiting on the vine, since a hard freeze can end ripening entirely, even indoors, for fruit still on a damaged plant.
15. It just needs more time
Even under ideal conditions, ripening does not happen overnight, and slightly cooler or warmer stretches within a normal range are expected along the way. If none of the other 14 reasons match what you are seeing, checking back in a week is usually all that is left to do.
If your tomatoes are staying green along with other unusual symptoms, you can use our Plant Diagnosis Tool to help identify what may be affecting the plant.
When Will Green Tomatoes Turn Red?
A mature green tomato in the 68 to 77°F range typically shows a blush within a few days and reaches full red in 1 to 3 weeks. Purdue University’s Yard and Garden program provides guidance on tomato ripening and temperature. Outside that range, in either direction, the timeline can stretch to a month or longer.
How to Tell If a Green Tomato Is Ready to Ripen
Press the fruit gently. Mature green gives slightly and feels firm, not rock hard. Check the blossom end for the faintest lightening, that early blush is called the breaker stage, and it means color change has already started internally.
Determinate varieties tend to set most of their fruit around the same time and ripen in a shorter window. Indeterminate varieties keep flowering all season, so a mix of green, breaker, and ripe fruit on the same plant at once is normal.
Leave it on the vine or pick at breaker stage?
If nights are staying above 50°F and no heat wave or frost is forecast, vine-ripening tends to give better flavor. If extreme heat, a cold snap, or frost is coming, picking at breaker stage and finishing indoors protects the fruit with little flavor tradeoff.
If frost is approaching, use our Frost Date Calculator to check your expected local frost timing and decide whether to leave tomatoes on the vine or bring mature green fruit indoors.
How to Get Tomatoes to Turn Red Faster
Ripening cannot really be sped up beyond its natural range, but you can remove the things slowing it down. Keep watering even, avoid heavy nitrogen after flowering, prune foliage that is shading a specific cluster, and shade fruit directly during an extreme heat spell. If you’re wondering how to turn green tomatoes red, the honest answer is fixing whichever of the 15 reasons above applies, then giving the fruit the 1 to 3 weeks it normally needs.
Can Green Tomatoes Ripen After You Pick Them?
Yes, as long as the fruit reached mature green or later before picking. Fruit that is still small, dark green, and hard, with no blossom-end lightening, usually shrivels instead of ripening once picked. Fruit that is full size, pale green to whitish, and gives slightly to a gentle press is a much better bet for finishing indoors.
Store picked tomatoes at room temperature, roughly 65 to 70°F, out of direct sun. Refrigeration below 55°F stops ripening and can affect flavor and texture, even in fruit that already started to color.
Sort fruit by stage rather than storing everything together. A batch of mature green tomatoes ripens on roughly the same schedule if kept apart from ones already at breaker or pink stage, which makes it easier to catch fully ripe fruit before it overripens rather than digging through a mixed pile every few days. Wrapping individual tomatoes loosely in newspaper works the same way as a shallow single layer in an open box, it slows moisture loss without trapping the kind of humidity that encourages mold.
Using a paper bag to help it along
Place one or two tomatoes in a paper bag with a banana or apple and fold the top loosely. Both fruits release ethylene, the hormone that triggers ripening, and the bag traps it around the tomato. Many gardeners see color within about a week using this method.
Why Are My Tomatoes Turning Orange, Pink, or a Different Color?
Orange or pink on the way to red is a normal midpoint for most varieties. Carotene tends to build slightly ahead of lycopene, so a brief orange phase before full red is expected rather than a warning sign.
A separate pattern worth flagging is yellow shoulder, hard yellow patches near the stem that never soften, with tough pale tissue underneath. That is usually tied to heat stress and potassium levels rather than a normal ripening delay, and it is worth checking soil potassium if you see it repeatedly.
Could Plant Stress Be Slowing Ripening?
A few additional factors can stack on top of the main causes above. None of these is usually decisive on its own, but together they can add days or weeks to the timeline, especially when combined with heat or cold that is already working against the plant.
Plant stress from transplant shock, root-bound containers, or recent disease pressure can all slow fruit development generally, ripening included. If one specific plant is lagging well behind others planted the same week under the same conditions, it is worth checking roots and overall plant health rather than assuming a temperature issue, since a struggling root system affects every part of the plant, not just the fruit closest to harvest.
Foliar diseases like early blight and septoria leaf spot reduce the leaf area a plant has for photosynthesis. A heavily defoliated plant has less energy available to push fruit through the final ripening stages, even if temperature and variety are not the issue. Removing infected lower leaves promptly and improving airflow slows the spread and helps the plant put more energy toward the fruit it already has.
Tomatoes Not Turning Red in Containers or a Greenhouse
Container and greenhouse tomatoes run into the same 15 reasons, but two of them show up more often in these setups. Worth checking first if your plants are potted or under cover.
Dark containers in full sun can heat the root zone considerably more than the surrounding air, especially when the container is small, which stresses roots and adds to heat delay even when daytime air temperatures look reasonable on a thermometer. Light-colored pots, or pots shaded at the base with mulch or a second container, reduce this effect. Patio and balcony tomatoes in small containers are especially prone to this since there is less soil mass to buffer the swings.
Greenhouses and hoop houses can trap heat far past outdoor temperatures if ventilation is limited, sometimes 15 to 20 degrees hotter inside than immediately outside on a sunny afternoon. Opening vents or doors during the hottest part of the day, adding a small fan for airflow, or using shade cloth on the roof panels during peak summer keeps interior temperatures closer to the ideal ripening range.
Indoors on a sunny windowsill, tomatoes ripening after picking do not actually need the sun exposure, room temperature and ambient air are what matter. A windowsill works fine because it is usually near room temperature, not because of the light itself.
How to Prevent Green Tomatoes Next Season
Most of this season’s ripening delays cannot be fixed retroactively, but a few planning changes reduce how often the problem shows up next year.
Matching variety to your growing season matters more than almost anything else. If your area regularly sees a long stretch of days above 90°F, or a growing season under 100 frost-free days, choosing varieties in the 55 to 70 day range gives more buffer against a late start or an early frost than a 90-day beefsteak does.
If your tomatoes are still green late in the season, check our USA Planting Calendar to see how your local growing season and planting timing may affect ripening.
Staggering planting dates by a couple of weeks, rather than putting every plant in the ground on the same day, spreads out the ripening window so a single heat wave or cold snap does not stall the entire crop at once. This also spreads out harvest instead of producing one large batch of green fruit all at the same stage.
Siting plants with morning sun and afternoon airflow, rather than a spot boxed in by fences or walls that trap heat, keeps ambient temperature around the fruit closer to that 68 to 77°F range during the hottest part of summer. Consistent spacing at planting time, rather than adjusting after the plants have filled in, avoids the airflow and humidity problems that come with a crowded row.
Finally, holding off on nitrogen-heavy fertilizer once flowering starts, rather than feeding on a fixed schedule regardless of growth stage, prevents the excess leaf growth that competes with fruit ripening in the first place.
Common Questions About Tomatoes Not Turning Red
Why are my tomatoes not turning red?
Most often it is temperature, either too hot or too cold for the enzymes that build lycopene. Immature fruit, heavy nitrogen, and varieties that never finish red are the other common reasons.
Why are my tomatoes staying green?
Full-size green fruit is usually just waiting on temperature to move back into the 68 to 77°F range, or waiting to reach the mature green stage internally in the first place.
Why won’t my tomatoes ripen?
Check the diagnostic questions above. Recent temperatures, fruit firmness, and variety usually point to the answer, most often heat, cold, or simply not enough time yet.
How can I make tomatoes turn red faster?
You cannot force it outright, but even watering, correcting excess nitrogen, light pruning near ripening clusters, and shading fruit during extreme heat all remove common roadblocks.
When will green tomatoes turn red?
Mature green fruit in ideal 68 to 77°F conditions usually blushes within days and finishes in 1 to 3 weeks. Heat above 90°F or nights below 50°F can push that out to a month or more.
What to Do If Your Tomatoes Still Won’t Turn Red
Run through the diagnostic checklist first. Fruit stage, recent temperatures, and variety explain nearly every case. If the fruit is mature green and frost, heat, or a growing-season deadline is approaching, pick it and finish ripening indoors rather than waiting on the vine.
Disclaimer: Information on this site is for educational purposes only. Results vary by climate, soil, weather, and growing conditions. For region-specific advice, consult your local USDA Cooperative Extension Service before making major gardening or soil changes.