Tomatoes are my arch nemesis. I work hard each year to plant enough tomato plants to provide the right amount of tomatoes I need for canning. Without fail, something goes wrong. Sometimes, my tomatoes don’t turn red. One day, blight infected my tomatoes. It’s always something.
For me, I like to find the answer to my questions. Why is something happening, or not happening in this case? In the case of tomatoes not turning red, there are some definite reasons.
Why Tomatoes Turn Red
There is a whole, scientific reason why tomatoes turn red, but let’s sum it up to make it easier to understand.
Lycopene is a chemical naturally found inside of fruits and vegetables that cause them to develop their color. Lycopene isn’t just found in tomatoes; it is in watermelons, apricots and more. Almost 80% of the lycopene you need in your diet is found in tomato products.
Believe it or not, your body processes lycopene better when it is heated. Sources such as ketchup and tomato sauce are perfect for getting lycopene into your diet!
Why do you need lycopene? It is valuable in the fight against heart disease, as well as some cancers (colon, pancreas, bladder, ovaries, and breast to name a few).
6 Reasons Why Your Tomatoes Aren’t Turning Red
1. Longer Time to Maturity
On each seed packet, you will find an average time for maturity for every vegetable you plant. You might be tempted to overlook this date, but I encourage you to pay attention! Certain varieties take less time to mature.
If you have a shorter growing season, you will want to select varieties with a shorter maturity time. It is a good idea also to plug in some longer growing varieties. You can rest assured knowing the shorter varieties will at least yield some fruits for you.
2. Temperatures aren’t Hot Enough
Tomatoes love warm temperatures, which is why you can’t plant them until well after your final frost date for the season.
Unfortunately, our weather in Ohio has been rather unpredictable, and chilly summers are becoming an issue. As I write this, it is the beginning of August and the high for the day barely touched 80 degrees. That is insane!
Sometimes, you will notice your tomatoes turning pink but never reaching the redness needed to indicate ripeness. They lack in flavor, but they will typically ripen if you leave them on your countertops.
3. Temperatures are TOO Hot
On the flip side, your tomatoes can be too hot for your tomatoes to ripen. High temperatures happened a few years ago, leaving my harvest in ruins. Yes, they love the heat, but they don’t want to roast on the vine.
The ideal temperatures for ripening are 70 to 75 degrees F. Once the temperatures go higher than 85 to 90 degrees F, the plant is unable to produce the correct amount of lycopene to create the right pigments. The green ones on your vine will stay green for a long time.
4. You Picked Tomatoes That Aren’t Red
If you grow heirloom plants, there are a lot of varieties that aren’t red. You can buy tomatoes that ripen to pink, yellow, white, orange, purple, and green! They make great additions to the dinner table and farmer’s market stand.
It is easy to forget what varieties you plant. You need to mark each variety, so you know what to look for in ripeness. For example, we always grow Brandywine tomatoes. Brandywine ripens to a beautiful pink, but they never turn red. If I forgot, I would let the entire harvest go to waste waiting for red tomatoes to arrive.
5. Blossom End Rot
Do your tomatoes have black lesions on them, small or big? If so, you have blossom end rot. It is a disease caused by low calcium in your soil. It is highly suggested that you add natural sources of calcium to your soil during the growing season.
Blossom end rot also forms from uneven watering. If you have frequent downpours of rain, blossom end rot can result.
6. Plants Don’t Receive Enough Sunlight
Another possibility is that you selected a bad location for your tomato plants. Tomatoes love heat and sunlight. The plants need at least seven hours of direct sunlight per day.
You might have picked a great location, but planted them too close together. Tomato plants need at least 18 inches to two feet apart, depending on the variety. Large plants, like the Brandywine, need two feet apart to receive adequate sunlight.
If all else fails, you can take some of your green tomatoes and put them in a cardboard box with a few ripened tomatoes. It should encourage the tomatoes to turn red! I know how it feels to have dozens of plants full of green tomatoes and end up with a pitiful harvest.