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.
Fresh Market Potato Varieties, Disease & Insect Management Twilight Meeting
August 25, 2016Growers will have a chance to review the fresh market varieties and Cornell breeding lines, including four European/Canadian varieties, in Walter DeJong's, Cornell on-farm trial. There will be an update on the new, very serious seed-borne bacterial disease, Blackleg Dickeya, including how to identify it, and how to reduce the risk of getting it next year, as well as updates on late blight, potato insect management and the development of a quick test for determining nematode levels in soils before planting.
5:00 PM - 8:15 PM
Sustainable and Organic Vegetable Pest Management Field Day
August 31, 2016Extension Vegetable Specialists, Darcy Telenko, Judson Reid, and Robert Hadad along with Abby Seaman, Vegetable IPM Coordinator, and Cornell faculty and staff Prof. Stephen Reiners, Holly Lange and Rachel Kreis from Prof. Chris Smart's lab will be leading research site tours and answering questions on sustainable and organic pest management options for fresh market vegetable growers. Information will be provided for both conventional and organic growers at all levels of expertise. Industry representatives will have the opportunity to meet with growers to comment on their products.
3:00 PM - 9:00 PM
2016 NYS Dry Bean Field Meeting
September 8, 2016Join us to view the Cornell Dry Bean Variety Trial, including 42 varieties/numbered lines of black, light and dark red kidney, cranberry and white kidney beans compared for yield, maturity, plant type and quality. Cornell lines bred for adaptability to NYS weather, pod height and white mold resistance are also included. There will also be updates on white mold and dry bean management research, and the status of the Western bean cutworm infestation in dry beans.
5:00 PM - 8:00 PM
Cucurbit Downy Mildew Confirmed in WNYCucurbit downy mildew has been confirmed in Cattaraugus County and southern Ontario County (near Naples). There have also been reports from MI, OH, PA and Ontario Canada. If you're planning on spraying cucumbers to control downy mildew, now is the time to do it!
Characteristic disease symptoms are angular, pale green areas bounded by the leaf veins. They will turn yellow and later necrotic. Under high humidity conditions sporulation will occur on the lower leaf surface. Apply targeted fungicides tank-mixed with protectant fungicides weekly and alternated among available modes of action (FRAC code), starting when there is risk for a specific crop based on forecasting program. Refer to the Cornell Vegetable Guidelines for a complete list of products available. For more information, contact Robert Hadad or Darcy Telenko.
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!