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

106 articles by this author

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This is the final issue of the Vegetable Crops Hotline (VCH) for 2017. Now is the time for subscribers who receive a paper copy in the mail to renew. A renewal form is included with this issue. Note that we provide an up-to three years’ subscription of VCH with a reduced price. You can also sign-up for Veggie Texts with the same form. 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. An Indiana Vegetable Grower Association (IVGA) membership form is included here too. IVGA membership no longer automatically includes the VCH subscription. You need to indicate you would like to subscribe the VCH on the membership form. Thank you very much for your support of VCH. If you have any suggestions, ideas, comments, please do not hesitate to[Read More…]


Winter is the best time to recharge. In the last issue of this years’ Vegetable Crops Hotline newsletter, I would like to highlight a few free webinar resources that I found very useful in the past season. Hopefully, you can also benefit from them, and have a productive winter. eOrganic webinars http://articles.extension.org/pages/25242/webinars-by-eorganic A lot of great information related to organic production, including using biofungicides, biostimulants and biofertilizers to boost crop productivity and help manage vegetable diseases; Management options for striped cucumber beetle in organic cucurbits; Impacts of the food safety modernization act on diversified organic vegetable farms, and a lot more. Commercial Horticulture Webinars by Alabama Cooperative Extension http://www.aces.edu/anr/beginningfarms/webinararchive.php The webinar series cover topics including irrigation, greenhouse crop production, plant disease management, insect pest management, weed management and more. Vegetable webinars by Michigan State University Extension http://msue.anr.msu.edu/program/beginning_farmer_webinar_series/vegetable_webinars The webinar series target for beginning farmers, topics include cover crops, season extension, plasticulture,[Read More…]


Consumers love cucumbers that are sweet, seedless and have thin skins. They are willing to pay high prices for the long or mini cucumbers sold at grocery stores. These cucumbers are often grown in greenhouses and shipped long distances. It will attract consumers’ attention if greenhouse type cucumbers can be produced locally in high tunnels, and be available in the early-season’s market. There are at least three benefits for targeting early-season cucumber production. First, prices are higher; second, there are less pest problems; and third, things are going slower in early seasons compared to in the summer. However, we all know that cucumbers love high temperatures and do not grow well when soil temperature is low, even in high tunnels. This is especially true for the greenhouse type cucumbers. The situation may be changed with the use of grafting technology. Using squash as rootstocks, we were able to harvest cucumbers[Read More…]


Strawberry production in Indiana primarily utilizes matted row systems, in which bare root strawberry plants are set in the spring, fruit is first harvested in the second year and plants are maintained for a few seasons. Strawberry production using an annual plasticultural system is popular in the southern states, at where strawberry is planted in the fall and harvested in the next spring. In the annual plasticultural system, strawberries have a longer harvest period and produce fruit with better quality. Growing strawberries as an annual crop is a challenge in Indiana. This is because our short fall makes it difficult for plants to reach the desirable sizes that lead to a sufficient yield in the following spring. This impression can be changed with the use of high tunnels that provide additional heat units and moderate frost protection. In a trial conducted in a 30 ×96 high tunnel at the Southwest[Read More…]


In the past season, we tested performances of eight specialty melons grown under high tunnel, greenhouse, hydroponic, and conventional field systems. The melon varieties we have tested in our trials include Lilliput, Inspire, Sugar Cube, French Orange, Tasty Bites, Escorial, Savor, and Artemis. Many of these melon varieties are Charentais (Cucumis melo var. cantalupensis). A specialty melon type with an outstanding fragrant smell. If you are wondering how to grow these specialty melons, please follow us at the Indiana Hort Congress. We will present what we have learned about growing these specialty melons under different production systems.


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Southwest Indiana Melon and Vegetable Growers’ Technical Meeting  Date: November 21, 2017 5:00 p.m. to 8:00 p.m. (EST) Location: Southwest Purdue Ag Center (SWPAC), 4369 N. Purdue Road, Vincennes, IN The meeting will start at 5:00 p.m. for board members to discuss topics for the March meeting, which will be held in French Lick, IN. Any member who wants to participate in the discussion is welcome. At 6:00 p.m., dinner will be served. Following that, we will showcase variety trials conducted at SWPAC in 2017, which includes seedless watermelons, melons, and personal-sized 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. 10. Any questions, please contact Wenjing Guan at guan40@purdue.edu  Illiana Vegetable Growers Symposium Date: 8 a.m. to 4 p.m. (CST) Jan. 4 2018 Location: Teibel’s Restaurant, 1775 U.S. 41,[Read More…]


Figure 1. Breakdown of young leaf tissues in the heart of a celery plant

Blackheart of celery is a physiological disorder that causes significant crop loss in major celery production areas. It is characterized by the breakdown of young leaf tissues in the heart of the plants (Figure 1). The affected young tissues turn black, which give it the name “blackheart”.  The cause of blackheart of celery is related to calcium deficiency in the fast expanding tissues, similar to the cause of blossom-end rot of tomato and tip-burn of lettuce. The symptom is more severe as plants approach maturity. Fluctuation in soil moistures; excessive soil fertility, especially nitrogen and potassium; and high soil salinity favor the development of blackheart. Varieties may show different tolerance to the physiological disorder. In addition, the problem can be prevented by avoiding wide fluctuation of soil moisture and over-fertilization. Drench application and foliar spray of soluble calcium direct to the heart of the plant may help to prevent the[Read More…]


Figure 2. Demonstration soil solarization in a high tunnel.

Soil solarization can be used as a tool for soil disinfestation. It is accomplished by covering moist soil with transparent polyethylene film for 4 to 6 weeks in the summer. During this period, soils are heated to temperatures that are lethal to many soil pathogens, nematodes and weed seeds. This summer we conducted a demonstration trial in one of the high tunnels at Southwest Purdue Ag Center. The high tunnel was divided into three parts that were covered with 6-mil plastic, 1.5-mil plastic, and no plastic. The 6-mil plastic is the old covering of the high tunnel, and the 1.5-mil plastic was purchased from a paint store. Air temperature and soil temperature at the depth of 12 inches were recorded. We saw little difference between temperatures of the soils covered with 6-mil plastic and 1.5-mil plastic, which indicated that the old coverings of high tunnels are as good as thin[Read More…]


Beginning Farmer East Regional Workshop Date: Oct. 28, 2017, 8:30 am – 4 pm Location: Randolph County Fairgrounds, 1885 U.S. Route 27, Winchester Attendees for this workshop can learn about: Business planning Pasture management Fruit and vegetable pest management Pastured poultry Greenhouse and high tunnel management Marketing products Purdue Extension experts will be available to discuss and answer questions. Cost is $10 and lunch will be provided. To register or find more information about the next four regional workshops, go to www.conf.purdue.edu/BegFarmerTours. Southwest Indiana Melon and Vegetable Growers’ Technical Meeting Date: November 21, 2017 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 5:00 pm for board members to discuss topics for the March meeting, which will be held in French Lick, IN. Any member who wants to participate in the discussion is welcome. At 6:00 pm, dinner will be served.[Read More…]


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Hydroponics Workshop II Date: Sep 8, 2017, 7:30 am – noon. Location: WSLR 116, Horticulture & Landscape Architecture 170 S. University St. Purdue University West Lafayette, IN 47907 Registration: http://tinyurl.com/yb4dnwrh For further questions contact Lori Jolly-Brown, ljollybr@purdue.edu, (765) 494-1296 In this workshop, you will learn about: LED lighting for winter produce in greenhouses Things to know about successful production in ‘vertical or indoor farms’ Biological control of insects Fertilizer recipes and injectors Ongoing research in our greenhouses Beginning Farmer East Regional Workshop Date: Oct. 28, 2017, 8:30 am – 4 pm. Location: Randolph County Fairgrounds, 1885 U.S. Route 27, Winchester. Attendees for this workshop can learn about: Business planning Pasture management Fruit and vegetable pest management Pastured poultry Greenhouse and high tunnel management Marketing products Purdue Extension experts will be available to discuss and answer questions. Cost is $10 and lunch will be provided. To register or find more information about the next[Read More…]