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You’ve waited. And waited. And waited some more. Your tomato plants are loaded with beautiful green fruit, but they’re just… sitting there. Green. Mocking you. Refusing to ripen.
Meanwhile, your neighbor’s tomatoes turned red weeks ago and they’re basically running a farmers market out of their driveway.
What gives?
Let me explain why tomatoes stay green and what you can actually DO about it.
## The Short Answer
Tomatoes need the right temperature to ripen. Too hot or too cold, and they just stop. Temperature is usually the culprit, but there are other factors too.
## Reason #1: Temperature Is Wrong (The Most Common Cause)
Tomatoes ripen best when temperatures are between 70-75°F. Outside that range, ripening slows or stops entirely.
### It’s Too Hot (Above 85°F)
When daytime temps consistently hit 85°F+ or nighttime temps stay above 70°F, tomatoes halt ripening. The pigments that create red color (lycopene and carotene) stop being produced in extreme heat.
How to tell:
– It’s midsummer and scorching
– Fruit is full-sized but staying green
– You live in a hot climate (Southwest, Deep South, etc.)
The fix:
– Wait for cooler weather: Temps will drop eventually, and ripening will resume
– Provide shade: Shade cloth over plants during hottest part of day
– Pick green: Harvest mature green tomatoes and ripen them indoors (see below)
### It’s Too Cold (Below 50°F)
When nighttime temps drop below 50°F, ripening slows dramatically. Below 40°F, it stops completely.
How to tell:
– It’s early spring or fall
– Nights are chilly
– Days are cool (below 65°F)
The fix:
– Wait for warmer weather
– Cover plants overnight: Row covers or blankets trap heat
– Pick and ripen indoors: Harvest mature green tomatoes before frost
## Reason #2: Too Much Nitrogen
Over-fertilizing with nitrogen creates lush, dark green foliage and delays fruiting and ripening. All leaves, no tomatoes.
How to tell:
– Plants look gorgeous and super green
– Tons of leafy growth
– Few flowers or fruit
– You’ve been fertilizing heavily
The fix:
– Stop nitrogen fertilization
– Switch to lower nitrogen, higher phosphorus/potassium fertilizer (5-10-10)
– Be patient—plants will eventually shift to fruiting mode
## Reason #3: Not Enough Sunlight
Tomatoes need 6-8 hours of direct sun for proper ripening. Shaded fruit stays green longer.
How to tell:
– Plants are in partial shade
– Fruit hidden inside dense foliage
– Some tomatoes ripening (the ones in sun) while others stay green
The fix:
– Prune excess foliage to let light reach fruit
– Can’t move plants? Harvest green and ripen indoors
– Next year, plant in a sunnier spot
## Reason #4: Plant Is Overloaded
When a plant has TOO MUCH fruit, it can’t ripen it all at once. Energy gets spread too thin.
How to tell:
– Plant is absolutely loaded with green tomatoes
– You haven’t harvested any yet
– Plant looks healthy otherwise
The fix:
– Harvest some green tomatoes to lighten the load
– Pick any damaged or diseased fruit
– Remove late-forming flowers that won’t have time to produce
## Reason #5: Variety Characteristics
Some varieties just take LONGER to ripen than others.
How to tell:
– Check your seed packet for “days to maturity”
– Cherry tomatoes ripen faster (50-60 days)
– Large beefsteaks take longer (75-90 days)
The fix:
– Be patient!
– Next year, choose early varieties if you have a short season
## Reason #6: Plant Stress
Stressed plants (from drought, pests, disease, or transplant shock) put energy into survival, not ripening.
How to tell:
– Plant looks unhealthy (yellow leaves, wilting, pest damage)
– Inconsistent watering
– Obvious disease or pest issues
The fix:
– Address the underlying issue (water consistently, treat pests, remove diseased leaves)
– Once plant recovers, ripening will resume
## How to Tell If a Tomato Is Ready to Pick Green
Not all green tomatoes are created equal. There’s “immature green” and “mature green.”
Mature green tomatoes WILL ripen off the vine. Immature ones WON’T.
Signs of mature green:
– Full size for the variety
– Glossy surface (not dull)
– Starting to show a pale or whitish color (called “breaker” stage)
– Seeds inside are fully formed (if you cut one open)
Immature green:
– Still growing/sizing up
– Dull surface
– Dark green color
– Will NOT ripen off the vine
Only pick mature green tomatoes for indoor ripening.
## How to Ripen Tomatoes Off the Vine
When frost threatens, or it’s too hot/cold for ripening, harvest mature green tomatoes and ripen them indoors.
### Method 1: The Cardboard Box Method
1. Harvest mature green tomatoes
2. Place in a cardboard box in a single layer
3. Add a ripe banana or apple (releases ethylene gas, which triggers ripening)
4. Close the box (but don’t seal airtight—they need some airflow)
5. Store at room temperature (65-70°F)
6. Check every few days and remove ripe tomatoes
Time: 1-4 weeks depending on how green they are
### Method 2: The Paper Bag Method
Same as above, but use paper bags for smaller quantities. Faster ripening due to concentrated ethylene.
### Method 3: The Windowsill Method
Place tomatoes on a sunny windowsill. They’ll ripen, but slowly.
Pro tip: Sunlight actually SLOWS ripening (counterintuitive, I know). Tomatoes ripen due to ethylene gas, not sunlight. Warmth + ethylene = faster ripening.
### Method 4: The “Leave Them On the Plant” Method
If no frost is threatening, just wait. They’ll ripen eventually when temperatures cooperate.
## Tips for Faster Ripening
1. Pick fruits that show even slight color change first
These are closest to ripe and will turn red fastest.
2. Use ethylene gas
Ripe fruit produces ethylene. Store green tomatoes with ripe bananas or apples to speed things up.
3. Keep temperature around 70°F
Too cool (below 60°F) = slow ripening. Too warm (above 80°F) = poor color development.
4. Don’t refrigerate
Cold temps (below 55°F) damage tomato cells and stop ripening. Plus, it ruins flavor.
5. Prune late in the season
4-6 weeks before first frost, remove new flowers and small fruit. This directs energy to ripening existing fruit.
## What NOT to Do
❌ Don’t put green tomatoes in the fridge: Stops ripening, ruins flavor
❌ Don’t leave them in direct sun: Slows ripening and can cause sunscald
❌ Don’t seal them in airtight containers: Causes rot
❌ Don’t expect immature green tomatoes to ripen: They won’t
## Can You Ripen Really Green Tomatoes?
If they’re mature green (full-sized, glossy), yes!
If they’re immature (small, dark green, dull), no. Use them for fried green tomatoes or salsa verde instead.
## End-of-Season Strategy
When frost is coming and you have tons of green tomatoes:
Option 1: Pick and ripen indoors
Harvest all mature green tomatoes. Use the box method.
Option 2: Pull the entire plant
Yank the whole plant (roots and all), shake off soil, and hang it upside down in a garage or basement. Fruit will continue to ripen on the plant for weeks.
Option 3: Make green tomato recipes
Fried green tomatoes, pickled green tomatoes, green tomato salsa—all delicious!
## Varieties That Ripen in Cooler Weather
Some varieties tolerate cool temps better and ripen more reliably in short-season or cool climates:
– Early Girl: Ripens in cool weather
– Oregon Spring: Bred for cool climates
– Stupice: Cold-tolerant Czech heirloom
– Glacier: Short season, cold-hardy
– Sub Arctic Plenty: For extreme cool climates
## The “Still Green in October” Panic Plan
Frost is forecast tonight and you have 50 green tomatoes. What do you do?
1. Harvest EVERYTHING mature
Any tomato that’s full-sized, even if dark green.
2. Sort by ripeness
– Reddish/orange: Will ripen in days
– Pale green (breaker stage): Will ripen in 1-2 weeks
– Dark green but mature: Will ripen in 2-4 weeks
– Immature/small: Use for cooking or compost
3. Ripen indoors
Use the box method. Check weekly and remove ripe ones.
4. Make fried green tomatoes
Because they’re delicious and you’ll have way more than you can ripen anyway.
## The Bottom Line
Tomatoes not ripening is almost always about temperature. Too hot, too cold, and they just wait for better conditions.
Quick fixes:
– If too hot: Provide shade or harvest and ripen indoors
– If too cold: Wait for warmer weather or harvest before frost
– If overloaded: Pick some green to lighten the load
– If shaded: Prune foliage to let light in
And remember: Tomatoes DON’T need sun to ripen. They need warm temperatures and ethylene gas. You can ripen them in a dark closet successfully.
So stop staring at them on the vine willing them to turn red, and either be patient or bring them inside to finish the job.
Your red tomatoes are coming. I promise. 🍅
