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

142 articles by this author

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This is the final issue of the Vegetable Crops Hotline (VCH) for 2016. Now is the time for subscribers who receive a paper copy in the mail to renew. A renewal form is included with this issue. You can also sign-up for Veggie Texts with the same form. More information about Veggie Texts can be found in ISSUE 615. Email subscribers will remain on the subscription list for VCH as long as the email address works. Email subscribers will need to send us an email or call us to sign-up for Veggie Texts. IVGA members will have their VCH subscription renewed when they renew IVGA memberships and do not have to send in a separate renewal form for the newsletter. An IVGA membership form is included here too. Thank you very much for your support of VCH. If you have any suggestions, ideas, comments, please do not hesitate to send[Read More…]



With the start of pumpkin harvest, it is a good time to review important considerations for harvest and postharvest storage of pumpkins and winter squash (butternut, acorn and hubbard squash etc.). First, pumpkin and winter squash should be harvested fully mature to reach their optimal quality and fulfill their potential for long shelf lives. Characters indicating fruit maturity include loss of rind surface gloss, ground spot yellowing, and hardening of the skin to the level that it is resistant to puncture with a thumbnail. Except for some striped varieties, mature fruit should have solid external color. If fruit have to be harvested pre-mature because of plant decline, these fruit won’t store as well as mature fruit. The best practice is to harvest the fruit as soon as they are fully mature and then store under proper conditions. If mature fruit are left attached to the vines, it increases the chance[Read More…]


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Southwest Indiana Melon and Vegetable Growers’ Technical Meeting  Date: November 28, 2016 5:00 PM to 8:00 PM (EST) Location: Southwest Purdue Ag Center (SWPAC), 4369 N. Purdue Road, Vincennes, IN The meeting will start at 5 P.M. for board members to discuss topics for the March meeting. Any member who wants to participate in the discussion is welcome. At 6 P.M., dinner will be served. Following that, we will showcase variety trials conducted at SWPAC in 2016, which include seedless watermelons, cantaloupes, personal-sized watermelons, and seeded watermelons. Any grower interested in becoming a member is invited to attend. Membership dues are $15 per year and can be paid at the meeting. To register please call (812) 886-0198. Registration is due by Nov. 22. Any questions, please contact Wenjing Guan at guan40@purdue.edu    Illiana Vegetable Growers Symposium Date: January 5, 2017 8:00 A.M. to 4:00 P.M. CST Location: Teibel’s Family Restaurant, 1775 US 41, US 30 & US 41, Schererville,[Read More…]


Beginning Farmer Tour Date: September 29, 2016 Location: River Ridge Farm, Roann, IN. This four-season farm produces vegetables and small fruits. The tour will include information about operating an on-farm store, farm-to-school, and four-season growing.The tour will be 9 A.M. – 3:30 P.M. (EST). Lunch will be served.The tours are free, but registration is required. Registration at https://mdc.itap.purdue.edu/wk_rules.asp?itemID=22368 Aquaponics Conference  Date: October 28-29, 2016 Location: Kokomo Event & Conference Center, 1500 N. Reed Road in Kokomo Aquaponics is a system that combines fish rearing and vegetable production. Topics include food safety of vegetables, pest control in aquaponics operations, indoor environmental conditions, vegetables for aquaponics, greenhouse structures and fish in aquaponics operations. Early-bird registration fee through Sept. 18 is $90 for Indiana Aquaculture Association Inc. (IAAI) members and $100 for non-members. After that date, registration is $100 for IAAI members and $125 for non-members. An optional tour of Green River Greenhouse can be added for an additional[Read More…]


Important Input Needed! Clear Choices Clean Water, in cooperation with the Office of the Indiana State Chemist and the Purdue Pesticides Program, is conducting a survey to guide state-wide pollinator protection efforts. How does this impact you? More than 1/3 of all plants or plant products consumed by humans are dependent on insects for pollination. Please help impact future protection efforts by participating today. The first 500 respondents get a FREE 2-ounce bottle of local honey! The pollinator survey is at: https://www.surveymonkey.com/r/pollinate This information is adapted from official announcement of the survey.


High Tunnel Tour at SWPAC Date: August 22, 2016 7:00 P.M. to 8:30 P.M. (EST) Location: Southwest Purdue Agricultural Center, 4369 North Purdue Road, Vincennes, IN 47591 Please join us for a high tunnel tour at the Southwest Purdue Ag Center. You will learn about high tunnel tomato diseases and management, end of season field sanitation, potential of grafting in high tunnel tomato production, use of shade cloth and sprayer calibration. Please feel free to bring samples for disease identification.  The tour is free, to register please call (812) 886-0198. If you need transportation, please let us know. For more information please contact Dan Egel at egel@purdue.edu or Wenjing Guan at guan40@purdue.edu.   Beginning Farmer Southeast Regional Workshop  Date: August 20, 2016, noon -7:30 P.M. (EST) Location: Purdue Polytechnic-New Albany, 3000 Technology Ave, New Albany, IN 47150 The workshop will cover a wide range of topics including high tunnel and hoop houses, food safety, vegetable production, pricing products, beginning[Read More…]


Figure 1. A 30% black shade cloth was added to one of the high tunnels

We have discussed the pros and cons of using shade cloth for growing high tunnel tomatoes in this article https://vegcropshotline.org/article/whether-to-put-shade-cloth-on-high-tunnel-tomatoes/ Shade cloth helps with reducing temperatures inside the high tunnel. But it also reduces light intensity that is essential for photosynthesis. To better understand to what extent can temperature and light reduced with a shade cloth applied on top of a high tunnel, We did a comparison this summer at Southwest Purdue Agricultural Center, Vincennes, IN, with one high tunnel applied with 30% black shade cloth, and the adjacent one did not (Figure 1). The following figures (Figure 2 and 3) illustrate how temperature and light levels in the high tunnel were affected by the shade cloth in a typical sunny (July 23) and a cloudy day (July 2). On both days, about 10 degree difference of maximal temperatures were observed between the two tunnels. On the sunny day of July[Read More…]


High Tunnel Tour at SWPAC Date: August 22, 2016 7:00 PM to 8:30 PM Location: Southwest Purdue Agricultural Center, 4369 North Purdue Road, Vincennes, IN 47591 Please join us for a high tunnel tour at the Southwest Purdue Ag Center. You will learn about high tunnel tomato diseases and management, end of season field sanitation, potential of grafting in high tunnel tomato production, use of shade clothe and sprayer calibration. The tour is free, to register please call (812) 886-0198. For more information please contact Dan Egel at egel@purdue.edu or Wenjing Guan at guan40@purdue.edu. Beginning Farmer Southeast Regional Workshop  Date: August 20, 2016, noon -7:30 pm Location: Purdue Polytechnic-New Albany, 3000 Technology Ave, New Albany, IN 47150 The workshop will cover a wide range of topics including high tunnel and hoop houses, food safety, vegetable production, pricing products, beginning farmer resources and beekeeping. A southern style barbecue will be provided. The workshop is[Read More…]


Figure 2. Cowpea was worked into the soil

We have grown strawberries from Aug, 2015 to May, 2016 in one of our high tunnels at Southwest Purdue Agricultural Center. After taking the strawberry plants out of the high tunnel in the end of May, we did have enough time to grow a warm-season crop, like cucumbers. However, because for most of us June is such a busy time working in the field, we decided to put cover crops inside the high tunnel in the summer months and plant cool-season crops in the fall. Our primary goal of growing cover crops is to provide nitrogen for the following crops and increase soil organic matter. We decided to use a legume cover crop cowpea in this case because it has excellent drought and heat tolerance. Cowpea at a rate of 100 lbs per acre was sowed on June 17th. With the high temperatures inside the high tunnel, cowpea reached 30’’ high[Read More…]