While it is possible to ripen green tomatoes off the vine in a paper bag or on a warm windowsill, success depends on the type of tomato, when it was picked, and the conditions you provide.
If you are new, these tips for growing tomatoes for beginners will help you get started.
Ripening Tomatoes Indoors
If you grow tomatoes in your garden, you know it is pretty common to end up with some green tomatoes during the growing season. Storms knock them off the vine, some crack open, or we simply run out of time and pick the fruit before the cold fall weather ruins them.
Unless you’re up for making fried green tomatoes, chutney, or relish, it is worth trying to ripen them indoors instead of tossing them straight into the compost pile.
Getting a tomato to turn from green to red (orange, yellow, pink, or whatever the final color should be) depends on three key things:
- the type of tomato
- whether the fruit was mature (at the “breaker” stage) when removed from vine
- growing conditions
Large, round tomatoes like beefsteak work best. Small, cherry tomatoes may either refuse to ripen or never taste sweet after forced ripening.
Age also matters. A tomato removed too early from the vine does not have the ability to ripen. It must be physiologically ripe to mature on or off the vine. There are tips for checking for maturity below.
But, if the tomato is near its “days to maturity,” there is a good chance, even when picked a bit early, it will ripen in your kitchen.
Contents
- Reasons Tomatoes Will Not Ripen
- How to Ripen Tomatoes
- Frequently Asked Questions
- How it Works
- Resources
Reasons Tomatoes Will Not Ripen
These are common reasons tomatoes will not ripen on the vine.
- The fruit is not mature. Tomatoes must be physiologically mature to ripen on or off the vine. This is called the breaker stage when the fruits contain viable seeds. The “days to maturity” listed on your seed packet will help identify the expected maturity date.
- Temperatures are consistently too low or too high.
Too low: daytime below 60°F (15°C) or nighttime below 50°F (10°C).
Too high: daytime above 90°F (32°C) or nighttime above 70°F (21°C).
Optimal warmth for ripening is 59-68°F (15-20°C).
It varies by variety but ripening tends to stall above 77°F (25°C).
- Low humidity and/or drought can also cause issues.
- Too much nitrogen. Fertilizers with high amounts of nitrogen can impede fruit growth.
Light is not an issue for ripening—the plant needs light to grow but not to ripen fruit.
How to Ripen Tomatoes
When growing tomatoes, “mature” and “ripe” are two different things. In order for a tomato to ever ripen, it must first achieve maturity—which can only happen on the vine. Once mature, it is capable of ripening on or off the vine.
Overview
- Select Mature Tomatoes
Only choose mature large, round tomatoes for indoor ripening, not small, cherry tomatoes.
If you are picking the green tomatoes from the vine, use snippers like these ones and keep the stems attached if you can.
Make sure there is no sign of damage or disease.
How to Check for Maturity
A key sign of maturity is the presence of gel-covered seeds inside. You can’t ripen a tomato once it is cut open, but, if you have several, sacrifice one to check for gel-covered seeds.
Handle the tomatoes with care: bruising and damage can lead to rot instead of ripening.
- Start Ripening Process Immediately
68°F (20°C) is the ideal temperature for ripening tomatoes
When tomatoes are stored first (in the fridge, for example) and ripened later, flavor and color are poor, so start the ripening process right away.
Gently wash and thoroughly dry the tomatoes.
If you have a lot of different tomatoes, sort by color, size, and age. This will make it easier to monitor changes.
Use a cardboard box with a lid and line it with newspaper or other absorbent cloth or paper.
Place the unripe tomatoes in the box. Do not let tomatoes touch.
If the tomatoes are in green stage 1, add a ripe banana or apple. These fruits emit ethylene, a naturally-occurring gaseous hormone that plays a role in ripening.
Take a photo to record the appearance and date. Close the lid.
Maintain even temperatures between 59-68°F (15-20°C ). A temperature of 68°F (20°C) is ideal.
Check your tomatoes every other day. Take photos to record progress. Remove any fruit showing sign of rot or mold. Switch out banana or apple as needed.
How long does it take?
Frequently Asked Questions
A warm temperature of 68°F (20°C) is ideal for ripening tomatoes indoors. You can only ripen a tomato if it is physiologically mature. The old-fashioned tip to put mature but unripe tomatoes (not touching) in a paper bag or cardboard box lined with newsprint with a banana or apple can help ripen them if the tomato is still fully green. Otherwise, it may not work. Ripening stops if the temperature exceeds 77°F (25°C). Sunlight or other light does not cause tomatoes to ripen. If they do not ripen, it may mean the fruit was not mature enough prior to picking.
Does this work for all types of tomatoes?
No. The type of tomato most likely to ripen after picking—if mature enough—are large, round tomatoes. Smaller cherry tomatoes either will not ripen or not taste sweet the way they should.
Does the flavor change when tomatoes are ripened indoors?
Yes, the flavor of tomatoes ripened off the vine can be somewhat bland compared to those left to ripen on the vine.
My tomatoes are green inside. Is this okay?
Sometimes the fruit will appear ripe on the outside but you cut it open to find it’s green on the inside. This means the fruit is probably not mature. It’s not harmful to eat but neither will taste good. Once the fruit is cut open, you cannot ripen it.
According to the Florida Tomato Committee, never store tomatoes under 55°F / 13°C. This ruins both flavor and firmness. Typical room temperatures above this (around 70°F / 21°C), are fine.
While right temperature along with high relative humidity (85-95%) is best for tomato longevity it’s not good for your home so just go with what you have.
Keep out of direct sunlight.
Store stem-up to prevent bruised shoulders.
What can I make with green tomatoes?
Fried-green tomatoes are the best-known traditional use for green tomatoes. Also consider making a green chutney or relish. Both are delicious and a good backup plan for making use of the fruit if you cannot ripen it indoors.
How it Works
There are a couple of factors that determine whether a tomato can ripen after picking and how long it will take.
It’s also important to provide the right ripening conditions so we not only get red tomatoes but tomatoes that taste great.
Factors Affecting Ripening
Type/Size of Tomato
- Large, round tomatoes are good candidates for ripening off the vine.
- Small (cherry) tomatoes are not. They may not ripen and flavor including sugar levels will decrease.
Maturity Level
The tomato has to be mature when picked to have a chance at ripening later.
- Mature is not the same as ripe.
- Gelatinous (jelly-coated) seeds are an indicator of physiological maturity.
Once a tomato has developed seeds, the ripening hormones can get to work.
While you can’t ripen a tomato once you have cut it open, it’s worth checking one to see if seeds are present and ripening is possible.
Example
In this next photo, I cut open two tomatoes.
The one marked YES has seeds protected by a gelatinous coating. This jelly-like stuff is a sign of maturity. It’s there to prevent the fully formed seeds from germinating within the fruit.
The green tomato has seeds forming but they do not yet have their jelly coats. That one would not ripen off the vine.
Ripening Stage
Once a tomato is mature, it goes through a series of ripening stages from green to red.
This is going to determine how fast the tomato can ripen, with the Green (stage 1) being the slowest and Light Red (stage 5) being the fastest.
I was interested to learn that Green stage 1 tomatoes can take the longest to ripen but also end up with the nicest flavor, color, and texture.
Ethylene
Ethylene is a gaseous plant hormone that plays a role in seed germination, vegetative growth, flowering, fruit ripening and more.
Because mature green tomatoes (stage 1) produce minimal ethylene, they are candidates for the ‘bag method’.
For that, the tomatoes are placed in a paper bag or other lidded container with another ethylene producing fruit such as bananas or apples to help trigger ripening hormones. I’ve provided complete instructions below.
But, once a tomato has some hint of red (stage 2 up), it’s already producing enough of its own ethylene that the bag method is not needed.
And yes, you can have too much ethylene.
Temperature
Tomatoes ripen best with consistent temperatures between 59-68° (15-20°C ) with 68°F or 20°C being optimal.
When temperatures are below or above this range, lycopene, and carotene (both key to ripening) cannot be produced.
We often think hot summer days are perfect for ripening tomatoes on the vine, but once the heat gets above 77°F (25°C), ethylene production stalls and the fruit struggles.
When trying to ripen off the vine, our instinct is to put the fruit in front of a sunny window, but light is not a ripening factor—temperature is—and, when too high, will overheat the fruit and cease ripening.
High humidity can also play a supporting role but does not seem worth recommending here since it’s not really realistic or desirable to crank up our household humidity just to ripen some tomatoes.
Darkness
As mentioned, light is not required for ripening off the vine and can inhibit key change agents. You’re better off following the instructions (below) and avoiding direct light.
How Tomatoes Change Color as They Ripen
Just like tree leaves, tomatoes start off green due to the chlorophyll. The color changes as the chlorophyll breaks down.
Once tomatoes reach maturity (with gel-coated seeds inside), ethylene gas is produced and lycopene increases.
Lycopene is an antioxidant carotenoid that gives tomatoes their red color and has many health benefits for us.
During ripening, the two keys to best flavor- sugars and acidity- also increase, and we end up with delicious, fresh tomatoes.
Resources
Tomato | Genus: Solanum
Tomato Growing Tips
Annual vegetable, truly a berry
• Vines (indeterminates) or bushes (determinates)
• Full sun – at least 6 hours total direct sun per day
• Soil: well-draining and fertile
• Propagation: seed or cuttings
• Self-fertile with help from wind and insects
• DIY tomato cages | Seed Saving | Ripen after picking
Shop Online: Buy tomato seeds at Botanical Interests (US Shipping)
or West Coast Seeds (Canada)
Book
Epic Tomatoes
How to Select & Grow the Best Varieties of All Time
by Craig LeHoullier
Craig LeHoullier provides everything a tomato enthusiast needs to know about growing more than 200 varieties of tomatoes, from planting to cultivating and collecting seeds at the end of the season.
Listen
Good luck with your fruit ripening!
~Melissa the Empress of Dirt â™›
How to Ripen Tomatoes Off the Vine
Equipment
- Cardboard box
- Newspaper
Supplies & Materials
- 5 Unripe but mature tomatoes large not cherry tomatoes
Instructions
- Select mature large, round tomatoes not small, cherry tomatoes. A key sign of maturity is the presence of gel-covered seeds inside. Cut the tomatoes from the vine (with stems intact to avoid damage) or take fruit that has recently fallen to ground. There should be no sign of damage or disease.Handle carefully to avoid bruising.
- Gently wash and thoroughly dry tomatoes.
- Sort tomatoes by color/stage. This will make it easier to monitor changes.
- Line box with lid with newspaper or other absorbent cloth or paper.
- Place unripe tomatoes in box. Do not let tomatoes touch. Add a ripe banana or apple if tomatoes are green stage 1.
- Take a photo to record appearance and date. Close lid.
- Maintain even temperatures between 59-68°F (15-20°C), ideally at 68°F (or 20°C).
- Check tomatoes every other day. Take photos to record progress. Remove any fruit showing sign of rot or mold. Switch out banana or apple as needed.Green tomatoes may take weeks to turn red.A pink tomato may only take days.
