Wenjing Guan

Vegetable Crops Hotline Editor & Clinical Engagement Assistant Professor
Department of Horticulture and Landscape Architecture
Area(s) of Interest: Commercial Vegetable and Melon Production
Wenjing Guan's website

168 articles by this author

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2018 Indiana Hort Society Summer Field Tour Date: June 26, 2018 Location: Garwood Orchards, 5911 W 50 South, LaPorte, IN 46350 More information about the field tour can be found at https://vegcropshotline.org/article/summer-field-tour-fruit-and-vegetables/ Small Farm Education Field Day Date: Aug. 30, 2018 Location: Purdue Daniel Turf Center (1340 Cherry Lane, West Lafayette, IN 47907) and Purdue Student Farm (1491 Cherry Lane, West Lafayette, IN 47906) Registration is $10. Register here http://www.cvent.com/d/hgqx6g For questions or reasonable accommodation needs, contact Lori Jolly-Brown  ljollybr@purdue.edu, (765) 494-1296.   Greenhouse and Indoor Hydroponics Workshop Date: Sep. 5, 2018 Location: 625 Agriculture Mall Drive, West Lafayette, IN 47907  


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We have received several calls recently reporting observations of leaf curling on tomatoes. Although several factors (disease, insect, herbicide, environmental stress etc.) could cause leaf curling, in late spring and early summer, we notice the majority of the leaf curling is caused by physiological factors that in general do not directly affect tomato yield and fruit quality. In a similar way to other vegetables, hot and dry conditions may cause leaf curling on tomatoes. In late spring and early summer, plants that are actively growing and developing fruit have a high demand for water. Under hot and dry conditions, plants respond by rolling the leaves to reduce the surface area exposed to high radiation. Lower leaves on a tomato plant are often affected first, they may recover if environmental stresses are reduced. But with some varieties, leaf curling may occur on most leaves of a plant and last for the[Read More…]



WEST LAFAYETTE, Ind. – Following the recall of pre-cut melon products sold in eight states – including Indiana – due to possible Salmonella contamination, Scott Monroe, Purdue Extension food safety educator, is reassuring consumers about the safety of the state’s melon crop. “The recalled melons were grown elsewhere,” Monroe said. “The 2018 Indiana cantaloupe and watermelon crops are planted and growing in the southwestern part of the state, but are not yet ready for harvest.” Indiana producers take food safety very seriously, he added. “There are a variety of practices that reduce the risk of contamination at the farm level,” Monroe said. “Among these are testing irrigation water, use of sanitizers in wash water, and employee training programs.” Amanda Deering, clinical assistant professor in Purdue’s Department of Food Science, noted that most Indiana watermelons and cantaloupes are produced on farms where food safety practices are monitored by third-party audits. “Growers are audited annually to ensure[Read More…]



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Southwest Purdue Ag Center High Tunnel Tour Date: June 13, 2018 7:00-9:00 pm Eastern Time Location: Southwest Purdue Agricultural Center, 4369 North Purdue Road, Vincennes, IN, 47591 Seedless cucumber production in high tunnels will be the highlight of this year’s event. You will see 16 cucumber varieties grown in a high tunnel, and be able to taste them. We will share with you yield results of grafted cucumber plants that have started to produce since middle April in an unheated high tunnel. You will also see cucumbers grown in the high tunnels with different pruning and trellising systems. Entomologist Laura Ingwell will join us at the event to discuss cucumber beetle management approaches. Other things you will see at this event include: summer squashes growing in a high tunnel; different pruning and trellising systems for growing tomato and pepper; annual strawberry production with low tunnel systems. Registration will begin at 6:30 pm. The tour[Read More…]


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Seal the Seasons is a growing food company founded on supporting local growers by making local food available all year-round. Seal the Seasons partners with local family farms on a state-by-state basis to source local food (focused primarily on fruit and vegetables), freeze it, and sell to grocers, with the grower proudly featured on the bag, in the grower’s state. Seal the Seasons has already successfully partnered with growers across the Southeast, Northeast and Mid-Atlantic and is looking forward to partner with growers in Indiana as it strives to support local agriculture and integrate quality Indiana frozen produce into conventional grocery stores. Any interested growers, food processors or copackers should reach out to Alex Piasecki at alex@sealtheseasons.com  


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Following the success of last year’s Summer Field Tour at Tuttle Orchards, this year we are again planning a combined summer field tour with the Indiana Horticultural Society, the Indiana Vegetable Growers’ Association and the Indiana Farm Market Association. We will be hosted by Garwood Orchards in La Porte, IN. While we encourage membership in these industry organizations, all those who are interested are welcome and invited to attend, regardless of membership status. Garwood Orchards is one of the largest and best managed orchards in the state. It may seem puzzling that they can manage such a large operation and manage it so well. That’s why we’re visiting – to not only be inspired but learn a few of their tricks and see how they do it. They have aggressively planted new cultivars and crops and have been on the forefront of adopting new technologies. They are major producers of[Read More…]


Figure 1. Blossom end rot of tomato.

We recently received several calls reporting blossom end rot of tomatoes (Figure 1). Although blossom end rot is caused by deficient supply of calcium to the developing fruit. The occurrence of this physiological disorder often relates to inconsistent supply of water. As a general rule, vegetables require 1-1.5 acre-inches of water per week. Since there is no rain in high tunnels, all the required water should be applied through irrigation. How does one determine if enough water has been applied to vegetables? This article provides some ideas. The first information needed is the irrigated area. For example, tomatoes are growing in a 30 × 96 high tunnel with 6 beds that are about 4 feet wide. Then the irrigated area is about 2,304 square feet (6 × 4 × 96 = 2,304). An acre has 43,560 square feet. So the irrigated area is roughly 2,304 / 43,560 = 0.05 acre.[Read More…]