There’s nothing more frustrating than watching your tomato plants thrive only to see their fruits stay green. Unfortunately, wishing and hoping won’t have them turning red any sooner.
Here, we are giving the hard truths and explaining what to do when those tomatoes won't turn red.
What Causes Tomatoes to Turn Red?
The red hue of tomatoes is due to lycopene, a natural pigment and antioxidant that collects in the fruit as it ripens under specific growing conditions. Lycopene makes the fruit eye-catching, ripe, and contains vitamins and nutrients.
There's a delicate balance between the chemical makeup and the genetics of the specific variety of tomatoes. Environmental factors like temperature and rain play a huge role in growing the perfectly blushing red tomato.
5 Reasons Tomatoes Won’t Turn Red
1. Fluctuating Temperatures
Tomato plants need temperatures of 70 to 75 degrees Fahrenheit to ripen. Anything above 85 degrees or below 50 degrees can halt any color change. This doesn't just put a stop to the ripening process but also prevents the tomato from maturing.
What To Do:
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Provide shade for plants during heat waves.
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Use row covers to retain warmth during cooler nights.
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Wait for temperatures to normalize.
2. Young Immature Fruit
Tomatoes need to reach their full mature size in order to start ripening. You’ll need to research your tomato variety and learn how many days it takes for a mature fruit to form. Patience is key, as tomatoes will only begin to change color once they’re fully developed.
What To Do:
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Research your variety of tomatoes, whether it’s a determinate or indeterminate variety, and how long it takes to bear harvestable fruit.
3. Lacking Proper Sunlight
All tomato varieties require full sun (daily direct sunlight for a minimum of 6 hours). Dense foliage shading the maturing tomatoes or planting in heavily shaded areas reduces the energy needed for tomatoes to turn red.
What To Do:
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Plant all tomato plants in an area with at least 6 hours of direct sunlight daily.
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Prune any leaves blocking fruit exposure to sunlight.
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Consider repositioning container plants or adding reflective surfaces.
4. Improper Soil Nutrients
Soil needs to have the proper nutrient makeup for tomatoes to flourish. Too much nitrogen and your plant will focus on producing leafy green foliage rather than plump red tomatoes. Too little and your plant will suffer from stunted growth and yellowed leaves.
Balanced fertilizer with the right mix of nutrients is essential to support flower and fruit production. It's best to pick a fertilizer with a 5-10-5 or 10-10-10 ratio. This is the ratio of nitrogen, phosphorus, and potassium (NPK).
What to do:
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Test your soil to check it has proper, balanced nutrients.
5. Lack of Pruning
Tomato plants with too many leaves, stems, or fruits can struggle to decide where to use their energy. Should they grow more leaves, produce more fruits, or focus on ripening?
Most of the time, they will choose to grow even more leaves and stems. Although your tomatoes may eventually turn red, this process takes much longer.
What to do:
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Remove suckers. Suckers are the small shoots that grow in the joint between the main stem and a branch of a tomato plant.
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Trim back 20 percent of the plant for added sunlight and less energy expenditure.
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Remove small immature fruits so the plant can focus on ripening the more mature tomatoes.
Tips From the Pros
Be Patient
Like all gardening woes, this is another lesson for us to slow down and practice patience. The good news? You can research tomato varieties that have a shorter harvesting time. That way, you don’t have to wait as long for a delicious vine-ripened tomato.
Some quick ripening varieties include:
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Sakura (Organic): Matures beautiful fruits in 55 days.
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Early Girl: A true winner that will mature in 57 days.
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Sun Gold: Supersweet and matures in 65 days.
Pay Attention to Weather Patterns
Like most things in life, weather can be unpredictable and out of our control. There may be seasons with unseasonably warmer or cooler temperatures or drier or wetter conditions that will affect the growing and ripening process.
Extreme heat can stop the production of the red pigment lycopene, while cooler temperatures can slow the overall development.
Tips for protecting your tomato plants from heat waves:
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Water thoroughly in the early morning hours. This locks in the moisture needed throughout the day without the risk of the sun's rays scorching the plant.
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Add some shade. You may need to assist your tomato plants by giving them a much-needed break from the sun. Add some shade by using a light cloth or using a temporary structure to provide some ease.
Excessive rainfall may stress the plant or waterlog the soil, making it harder for the tomatoes to mature properly.
Pro Tip: Be sure to never overwater your tomato plants, as this can have the same effect.
Tips for protecting your tomato plant from excess rainfall:
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Add a thick layer of organic mulch around the base of the tomato plant. This acts as a barrier to prevent root rot and can absorb some extra moisture.
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Trim the bottom leaves off the base of the tomato plant. This helps provide extra air circulation and fends off fungal disease.
How Long Does it Take For Tomatoes to Turn Red?
On average, it takes anywhere from 40-50 days for a fruit to form from a pollinated flower and another 20-30 days to turn red and ripen, so about 60 to 80 days total. This of course depends on the variety of tomato plants.
Does this mean you can only harvest a tomato after it has turned red? Not exactly. You can harvest a green tomato if it has reached the most mature stage of development.
This happens when the fruit is full-sized and firm and starts to show a slightly lighter color at the tomato's base. With the right conditions these fruits can easily ripen right on your countertop!
But if you harvest a tomato before it reaches its most mature stage, it won’t develop the deep red color or the flavor profile associated with those vine-ripened tomatoes we all know and love. For the best results, let the tomato mature before plucking it off the vine.
5 Ways to Help Tomatoes Ripen Indoors
Once you have done everything that you can to ripen the tomatoes on the vine, there will come a point where Mother Nature will take over. Fall will come, but you may still have unripe tomatoes on the vines.
So what do you do? Here are some suggestions.
1. Pick Them and Bring Your Tomatoes Inside.
If you only have a few partially ripened tomatoes left, pick them and bring them indoors. Put them on the kitchen counter or on the windowsill to ripen.
2. Bring Your Container Tomatoes Inside.
If you are growing your tomatoes in a container garden, move the entire pot and tomato plants indoors to continue growing. Place the pot in a sunny window and you are all set.
3. Try a Paper Bag or Box to Ripen Your Tomatoes.
If you want to speed up the process, place the unripened tomatoes in a paper bag or cardboard box with an apple or banana. The apple or banana will give off ethylene which stimulates the tomato to ripen. By placing them together in a bag or box, you will ensure the tomato is exposed to the ethylene.
Do not use a plastic bag as the plastic will cause the humidity to rise and promote the growth of fungi and bacteria.
4. Hang Your Entire Tomato Plant Indoors.
If you have a lot of tomatoes still on the plant, pull the entire plant — root and all — out of the ground. Hang the tomato plant upside down in the garage or basement. Be sure the area you hang the plant will have a temperature above 50 degrees. Check the plant daily, and you will easily see which tomatoes are ready to pick.
5. Pick and Wrap Your Tomatoes in Paper.
This method has been used for many years as a way of storing fresh tomatoes. Pick and wrap each tomato individually in paper. Place your wrapped tomatoes in a single layer in a box and store them in the basement. Check the tomatoes frequently for progress.
Obviously, that is the negative part of this system. The tomato wrapper must be opened to check it for ripeness. However, by individually wrapping each tomato, you protect them from their neighbor. If a tomato should go bad, it is not touching the next tomato and will not spread the problem. Gardeners who use this system report they are still eating fresh tomatoes a couple of months later.
How to Store Your Ripened Red Tomatoes
Hopefully, you have enjoyed eating fresh ripe tomatoes all summer, or you’ve employed some of the tips and tricks above and you’ve got plenty of red tomatoes to use. If you’re suddenly experiencing an excess of tomatoes, why not try canning or freezing? Not everyone is interested in canning, but freezing excess tomatoes is simple and a great way to save tomatoes at the end of the year.
To freeze tomatoes, simply wash them and then remove the stem end. This is easy to do if you repurpose your melon baller and use it to remove the stem end cleanly and neatly. Then, just place the tomato in a freezer bag until you are ready to use it. This is great when you maybe only have one or two tomatoes ripening each day. Just add them to the bag of frozen tomatoes until the bag is full.
When you are ready to use the tomatoes, remove the amount you want. As they start to defrost, the skin will slip right off. These tomatoes will be best added to soups and sauces.
If you do want to preserve your tomatoes by canning, take time to read a current canning instruction guide. Canning tomatoes is not difficult, and you can process tomatoes in a water bath — just a fancy way of saying in a large kettle of boiling water. There is no need for a pressure canner.
Make Something Delicious with Green Tomatoes
If you aren’t sure you want to try to extend the tomato season with these methods or you tried them and you still have green tomatoes, it might be time to get out the cookbook and try using your green tomatoes as they are. Fried green tomatoes are delicious, and the recipe is easily found online. Try pickled green tomatoes, a tangy green tomato salsa, or a green tomato relish. You may have just found your new favorite burger topping or chip dip, which is perfect for summer! You can also try making your own homemade salsa verde — just substitute green tomatoes for the tomatillos.
If all else fails, use your tomato vines and any unripe tomatoes by adding them to your compost.
Wrapping Up
Watching your hard work pay off into beautifully ripe tomatoes is super rewarding. But knowing the right steps and pro tips makes all the difference. Now that you have an understanding of what may be keeping your tomatoes from turning red and how to help them along, you're on the path to delicious yearly tomatoes grown right in your backyard.
If you're ready to expand your tomato garden, check out the Park Seed Tomato Collection for some of the best varieties.
