Why do some tomatoes stay green and never turn red?
Written by
Tina Carter
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.If you're tired of green tomatoes that won't ripen to their luscious best, here are five good reasons why the colour change won't (and can't) happen.
Nutrient Imbalances
- Calcium deficiency disrupts lycopene and carotenoid production
- Excess nitrogen promotes foliage over fruit ripening
- Low potassium reduces sugar conversion needed for color change
- Soil pH below 6.0 limits nutrient absorption
Environmental Stressors
- Temperatures above 90°F halt pigment development enzymes
- Night temperatures below 55°F slow metabolic processes
- Insufficient sunlight under 6 hours daily delays ripening
- Water stress from drought or flooding stalls maturation
Genetic factors account for many green tomatoes that retain the same vivid green color when mature. Varieties such as Green Zebra and Aunt Ruby's German Green develop full flavor without turning red, designed to stay on the vine, as their namesake suggests. Fruits show only a hint of cream or yellow underneath and should be harvested when slightly soft at the blossom end.
Preventive measures begin even before you plant. Test the soil before planting to determine its nutrient levels. Amend with compost and a balanced fertilizer. Select vegetable varieties that are suited to your climate. Ensure the plants have a steady water source, such as drip lines, if possible. Monitor temperatures and use protective covers when necessary.
*Rescue techniques:* There is a perfect solution for affected green tomatoes. Pick those mature greens before the frost hits, and ripen indoors among bananas. Have fun: deep fry those little critters or make them into chutneys. That fabulous antioxidant is hiding in green tomatoes, despite their color! Of course, do not eat raw green tomatoes of the ornamental variety.
Read the full article: When to Harvest Tomatoes for Best Flavor
