Why Aren't My Tomatoes Ripening?
Steve Reiners, Co-Team Leader, Cornell University
Eastern New York Commercial Horticulture
August 22, 2012
With all of the hot weather we have experienced this summer, growers were expecting their tomatoes to ripen very quickly. Unfortunately, just the opposite is happening. Ripening seems very slow, almost like what we see in the autumn when temperatures are much cooler.
So what's happening? It takes six to eight weeks from the time of pollination until tomato fruit reach full maturity. The length of time depends on the variety grown and of course, the weather conditions. The optimum temperature for ripening tomatoes is 70 to 75F. When temperatures exceed 85 to 90 F, the ripening process slows significantly or even stops. At these temperatures, lycopene and carotene, pigments responsible for giving the fruit their typical orange to red appearance cannot be produced. As a result, the fruit can stay in a mature green phase for quite some time.
Light conditions have very little to do with ripening. Tomatoes do not require light to ripen and in fact, fruit exposed to direct sunlight will heat to levels that inhibit pigment synthesis. Direct sun can also lead to sunscald of fruit. Do not remove leaves in an effort to ripen fruit. Also, soil fertility doesn't play much of a role. We do know that high levels of magnesium and low levels of potassium can lead to conditions like blotchy or uneven ripening or yellow shoulder disorder. But the slowness to ripen is not likely due to soil conditions and adding additional fertilizer will do nothing to quicken ripening.
If you absolutely cannot wait, some growers will remove fruit that are showing the first color changes. These fruit, in the a mature green or later phase, could be stored at room temperature (70-75F) in the dark. A more enclosed environment would be best as ethylene gas, released from fruit as they ripen, will stimulate other fruit to ripen. If temperatures remain high outdoors, these picked fruit will ripen more quickly, perhaps by as much as five days. As far as flavor, the greener fruit should develop flavor and color similar to what you would get if field ripened. The key is picking them when they are showing the first signs of ripening (no earlier) and keeping them at room temperature. Do not refrigerate, as this will absolutely destroy their flavor.
Muck Donut Hour Every Tuesday
June 7, 2016Meet with Cornell Vegetable Program Specialist Christy Hoepting every Tuesday morning to ask questions and share your observations.
8:30 - 9:30 AM
Hands-on Field and Vegetable Pest Management
June 8, 2016This course will educate growers on weed and insect identification and management in mixed field crop and vegetable systems; with additional focus on integrated weed management. Topics such as resistant varieties, pest/disease, cultural management and appropriate spray options will be included
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Muck Donut Hour Every Tuesday
June 14, 2016Meet with Cornell Vegetable Program Specialist Christy Hoepting every Tuesday morning to ask questions and share your observations. Grower experience is combined with research and scouting information for a whole lot of talk about growing ONIONS!
8:30 - 9:30 AM
Cornell High Tunnels Website RedesignedThe Cornell High Tunnel website has been redesigned to help farmers profit from the use of high tunnels to extend their growing season and produce higher quality vegetables, fruit and flowers. The site contains information on the different types of structures and the resources for high tunnel profitability. Events, Tweets by Judson Reid, and the latest blog articles are accessible as well.
Assisting Western New York Vegetable GrowersWestern New York is a national leader in vegetable production and the largest vegetable producing region in the state of New York, contributing an estimated $280 million to the state's economy each year. The region grows a diverse set of crops including tomatoes, potatoes, sweet corn, pumpkins, cabbage and peppers on large acres, and another 50 crops on smaller plantings.
The Cornell Vegetable Program's video, "Meet the Cornell Vegetable Program" provides an introduction to our team of specialists and how we assist vegetable growers throughout the region. We greatly appreciate that several WNY vegetable growers shared their thoughts on what the Cornell Vegetable Program means to them: Paul Fenton, Batavia; Mark Zittel, Eden; and Matt Mortellaro, Elba. Watch the video now!
2016 Cornell Vegetable Guidelines AvailableThe 2016 edition of the Cornell Commercial Vegetable Production Guidelines is available. This annual publication provides up-to-date vegetable crop production information for New York State. It has been designed as a practical guide for vegetable crop producers, crop consultants, and ag suppliers. In addition to the annually revised pesticide and crop production information, this edition also includes the addition of several new pests of concern (seedcorn maggot in beans, leafminers in lettuce and endive, spider mites in peppers, anthracnose in spinach, and powdery mildew in tomatoes), a new table listing biofungicide options for vegetable production, revised management strategies for striped cucumber beetle in cucurbits and Stewart's wilt in sweet corn, and identification of pesticide active ingredients that meet EPA's criteria for acute toxicity to bees.
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