Tomatoes, although botanically considered fruits, are a remarkable vegetable. Not only are they a superfood rich in vitamins and minerals, but they are also incredibly easy to grow and remain a high-yielding plant. There is nothing more frustrating than being faced with a green or yellow “collar” on the plants in anticipation of the tomato harvest that stubbornly refuses to ripen. These areas are appropriately called yellow and green collars and are hard to the touch, especially compared to the rest of the ripe parts of the fruit. Discover helpful tips here on how you can avoid yellow and green collars on tomatoes. Luckily, it's very easy.
The green and yellow collars on tomato plants is a physiological disorder characterized by discolored areas under the peel that affects the quality of the fruit. The yellow and green spots are not a result of delayed maturation, but rather an actual disease of the affected tissue.
- Lycopene
There are several reasons why some parts of tomatoes remain green or yellow while the rest of the fruit ripens. The first has to do with lycopene production. Lycopene is a plant pigment that gives tomatoes their red color. The ideal temperature for the development of lycopene is 18 – 24 ºC. If the temperature rises above 24ºC and is sustained, lycopene production is inhibited.
The irony is that tomatoes like heat. The plants can tolerate temperatures higher than 24ºC throughout the summer. But it is the direct sunlight that determines what happens on the fruit. The top parts of the vegetable are usually the strongestexposed to heat or sunlight. When the sun hits the tops of tomatoes, temperatures in the fruit rise and inhibit lycopene. Without precautions, these parts cannot produce lycopene and they remain green.
- Chlorophyll
Another reason parts of vegetables stay green has to do with chlorophyll, the pigment that gives plants their green color. Excessive heat prevents chlorophyll from breaking down. So when ripening green tomatoes lie in the direct, hot sun for hours, the chlorophyll is retained. If you combine the persistence of chlorophyll with the inhibitions of lycopene, the vegetables turn green where the red should actually break through.
Tomato deficiency symptoms: the yellow collars
Carotene, which is another pigment in tomatoes, produces yellow and orange. It is less affected by heat. When higher temperatures and hot sun hit tomatoes, carotene (yellow) shines through while lycopene (red) is suppressed. The lower part of the vegetable is often protected from direct sunlight by the upper part of the fruit. This allows the top parts of your tomatoes to remain yellow while the rest ripen red.
Can you eat tomatoes with green and yellow collars?
If you've ever eaten an unripe tomato, you know that it's usually sour and hard. Green and yellow collars on tomatoes also taste like this. Luckily, the rest of the vegetables remain unaffected and are completely safe and delicious to eat. Just cut off the collars and it will feel like your green spot problems never existed.
Avoid yellow and green collars on tomatoes
Tomatoes that already have green or yellow spots can no longer be corrected, so it is best to prevent the discoloration in the next harvest. Fortunately, there are ways to prevent these tomato problems before they happen.
Minimize pruning
Pruning tomato plants is optional and, in most cases, an aesthetic decision. Some gardenerscut back some leaves, to keep the plant in order or to influence the fruit size. Keeping pruning to a minimum will help protect your tomato fruits. The foliage of a more heat-tolerant tomato plant can shield the tomatoes as they ripen.
Green collar on tomatoes: Shade is important
Partially shading your tomato plant, especially in high heat, can maximize photosynthesis and reduce heat buildup in the plant. One way to provide shade is to plant the tomatoes in spots in your garden that provide natural shade during the day. You can plant them on an east-facing wall so that they receive full morning sun but are protected from the harsher afternoon sun. As a temporary solution, you can install a fabric shade. Depending on how much shade the plant needs, you can adjust the density of the fabric.
Choose the right variety
Some tomato varieties are more susceptible to green collar than others: use hardy varieties instead. When buying your seeds or young plants, pay attention to which varieties are susceptible. There may also be resistance on the seed packageagainst this diseasebe specified – ideal for extremely hot climates.
Pick your tomatoes early
To prevent green and yellow collar, allow your tomatoes to ripen on the vine by picking them early. This method is only suitable for extreme cases because you could accidentally pick the tomato before it is fully ripe, affecting its flavor. The best time to pick early is when the red pigment begins to shine through the green. After harvesting, you can leave the tomatoes on the counter where they will continue to produce ethylene gas, which promotes their ripening. To speed up ripening, store them with fruits that also produce ethylene gas, such as bananas or apples.
