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

245 articles by this author

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Veg Crops Hotline - COVID-19 Image

New 5-7-2020: COVID-19 response plan template and FAQ for fruit and vegetable farms from UMN; Guidelines to Exercise Essential Status for a Farmers’ Market; SBA Covid19 disaster loans for Indiana small business What is new? (5-7-2020) COVID-19 response plan template and FAQ for fruit and vegetable farms from UMN. https://blog-fruit-vegetable-ipm.extension.umn.edu/2020/04/covid-19-response-plan-template-and-faq.html This template can help you plan and communicate with others about changes in your operation that are needed to deal with the corona virus pandemic. Guidelines to Exercise Essential Status for a Farmers’ Market https://www.purdue.edu/dffs/wp-content/uploads/2020/05/COVID-DFFS-INDIANA_Farmer-Market-Guidelines.pdf SBA COVID-19 DISASTER LOANS FOR INDIANA SMALL BUSINESSES (link update 5/7) https://isbdc.org/indianacovid19smallbusiness/ https://www.sba.gov/funding-programs/loans/coronavirus-relief-options Here are the categorized information resources Financial SBA COVID-19 DISASTER LOANS FOR INDIANA SMALL BUSINESSES (link update 5/7) https://isbdc.org/indianacovid19smallbusiness/ https://www.sba.gov/funding-programs/loans/coronavirus-relief-options SBA Help for Small (and Family) Businesses, Purdue Institute for Family Farms (update) (4/28) https://ag.purdue.edu/agecon/fambiz/Documents/SBA_Help_for_Small_Businesses.pdf COVID-19 Affected Business and Employee Resource Guide from Sen. Braun (3/27) https://www.braun.senate.gov/sites/default/files/2020-03/Senator%20Mike%20Braun%20COVID-19%20Affected%20Business%20and%20Employee%20Resource%20Guide_0.pdf Information about the Coronavirus Aid, Relief,[Read More…]


Veg Crops Hotline - COVID-19 Image

New 4-23-2020: Safety for Farm Children During COVID-19 Stay-at-Home Orders; Be Careful When Employing Youth to Do Farm Work This Spring – Know the Laws  What is new? (4-23-2020) Safety for Farm Children During COVID-19 Stay-at-Home Orders https://extension.purdue.edu/INPREPared/wp-content/uploads/2020/04/COVID-and-Farm-children.docx Be Careful When Employing Youth to Do Farm Work This Spring – Know the Laws https://extension.purdue.edu/INPREPared/wp-content/uploads/2020/04/Be-Careful-When-Employing-Youth-to-do-Farm-Work-–-Know-the-Laws1.docx Here are the categorized information resources Financial SBA Help for Small (and Family) Businesses, Purdue Institute for Family Farms (4/16) https://ag.purdue.edu/agecon/fambiz/Documents/SBA_Help_for_Small_Businesses.pdf COVID-19 Affected Business and Employee Resource Guide from Sen. Braun (3/27) https://www.braun.senate.gov/sites/default/files/2020-03/Senator%20Mike%20Braun%20COVID-19%20Affected%20Business%20and%20Employee%20Resource%20Guide_0.pdf Information about the Coronavirus Aid, Relief, and Economic Security (CARES Act); the Families First Coronavirus Response Act; and Small Business Economic Injury Disaster Loans (EIDL). SBA COVID-19 DISASTER LOANS FOR INDIANA SMALL BUSINESSES (3/19) Apply : https://disasterloan.sba.gov/ela/ Instructions: https://disasterloan.sba.gov/ela/Documents/Three_Step_Process_SBA_Disaster_Loans.pdf Production A Guide for Community Gardens During the COVID-19 Pandemic (3/25) https://extension.purdue.edu/article/36666  Purdue Crop Chat Podcast Episode 2, COVID-19 Implications (3/25) https://www.hoosieragtoday.com/purdue-crop-chat-podcast-episode-2-covid-19-implications/ Labor and Family[Read More…]


At Southwest Purdue Agriculture Center in Vincennes, IN. We are conducting trials to evaluate annual plasticulture strawberry production systems. Here are the updates of strawberries from different production systems. In a high tunnel, harvest of fall-planted strawberries started in early April. Cultivars Sensation, Radiance, Ruby June were early cultivars; followed by Beauty, Fronteras. So far, Radiance led the yield. Chandler, San Andreas, Camarosa, Liz and Camino Real were relatively later cultivars. In the open field, most cultivars of fall-planted strawberries were in full bloom. As mentioned in the article Strawberry Cold Protection Made a Difference, they are susceptible to frost damage. Cold protection is critical for them at this stage. Row cover was successfully used to protect the flowers from frost damage last week. Day-neutral strawberry cultivars planted on March 9, 2020 established well. Plants were slightly larger under low tunnels. Frost happened last week killed most of the initiated[Read More…]


USDA is open for business. Our team is continuing to provide the best customer service we can while also prioritizing the health of our employees, the health of our customers, and the health of our partners. USDA’s Service Centers are open in Indiana by phone appointment only. While our program delivery staff will continue to come into to the office, they will be working with our customers by phone, by email, and using other online tools whenever possible. To learn more about USDA programs and the Department’s response to the Coronavirus visit farmers.gov/coronavirus or www.rd.usda.gov/coronavirus. To locate your local Service Center, visit farmers.gov/service-locator.  


Two types of injury on young warm-season vegetable plants are caused by low temperatures: frost/freezing injury and chilling injury. Frost/freezing injury occurs when temperatures drop below 32°F. Ice formation in plant tissue cuts cell membranes. When the tissue thaws, the damage results in fluids leaking from the cell, causing water soaked damage. Frost/freezing injury is detrimental to warm-season vegetables, such as melons, cucumbers, tomatoes, peppers, and beans. To avoid damage, the best way is to plant warm-season vegetables later in the spring, after the last frost has passed. However, weather is difficult to predict, and there is a growing trend of planting early to achieve early harvests. For the early planted warm-season vegetables, here are a few suggestions that may protect plants from low temperature damages. Covering. The idea of covering the seedlings is to create a microclimate around plants. Because the heat accumulated in soil irradiate back at night,[Read More…]


Figure 2. Cold damage on 'Popcorn' stage strawberry flowers.

Spring weather is unpredictable. One of the major risks associated with strawberry production is cold damage in the spring. Open strawberry flowers can not tolerate temperatures lower than 30°F, popcorn stage flowers and tight buds may tolerant temperatures low to 26 and 22°F, respectively. If strawberries are in the early blooming stage, the damage might be delayed harvest. However, if strawberries are in full blooming stage, low temperatures may cause dramatic yield loss. This is because inflorescences are initiated at day length <14h (June-bearing cultivars). If all the flowers were killed by low temperatures before setting fruit, there would be no more flowers for the year. In this article, we update the cold damage that happened last week on plasticulture strawberries in Vincennes, IN. Figure 1 is the recorded temperatures (°F) at the height of strawberry canopies from 2:00 pm Apr. 13— 1:00 pm Apr. 18. Temperatures dropped below 30°F[Read More…]


Figure 1. The two flowers on the left are in 'Popcorn' stage.

Warm temperatures this week greatly encouraged strawberry growth and development. Some of the early cultivars may have entered the open blossom stage especially if they are grown with the annual plasticulture system in southern Indiana. Open flowers cannot tolerate temperatures lower than 30°F, while popcorn stage flowers (Figure 1) and tight buds may tolerant temperatures low to 26 and 22°F, respectively, according to information from Barclay Poling from NCSU. Lower than threshold temperatures may completely kill flowers or damage flowers that lead to misshaped fruit. Depending on the crop stages, this may result in devastating yield losses and/or delay the start of harvest season. According to USDA Midwest Climate Hub briefing, warm temperatures this week will be followed by several days of freezing chances this weekend into early next week, and cold is likely through mid-April at least. The current forecast in southern Indiana predicts low temperatures that are in[Read More…]


We know from published research that the health and quality of a vegetable transplant affects how it will establish, grow, and yield in the field. Our recent work comparing tomato and cucurbit seedling growth in different organic growing media and with and without added fertilizer has provided some good examples of this. See Vegetable Crop Hotline issues 653 and 668 for descriptions of media. Tomatoes flowered and set fruit earlier, and had greater early yield when the seedlings were grown in a media that sustained good growth (Figure 1), or if in a media with low fertility but were provided additional nutrients from solid or liquid fertilizer (Figure 2). What does this mean for transplant producers? Plan to provide nutrients the seedlings need, either pre-mixed in the growing media or by adding fertilizer. Among the media for organic production that we tested, additional fertilizer was most beneficial to those media[Read More…]


Dear Vegetable Crops Hotline readers, Firstly, I want to let you know the status of a few Purdue Extension Events related to fruit and vegetable growers. That PSA Grower Training in LaGrange County that was planned on March 20 was canceled due to concerns about the spread of coronavirus (COVID-19). A Strawberry Workshop that planned to be held in May at Southwest Purdue Agricultural Center may need to be canceled or delayed. We will let you know the decision soon. The Hydroponic Workshop that was planned to be held in June or July at West Lafayette, and the Small Farm Education Field Day that planned to be held on July 30 at Purdue Student Farm, West Lafayette, do not expect changes at this point. We will keep you posted about the details of our coming events. Meanwhile, please read the article below about what you should know and how to[Read More…]


Dear Watermelon Growers, At our past winter technical meeting, several growers suggested fertilizer recommendations need to be reevaluated for watermelon production in our area. This suggestion is timely and critical. We plan to initiate a project for the 2020 watermelon production season to reevaluate the fertility and irrigation practices used in Indiana.  We will identify 7-10 watermelon fields with different irrigation and fertility practices. We will collect soil samples and plant tissue samples at different crop growth stages. Lab results will be shared with growers immediately after they are received. Growers who wish to closely watch the nutritional status of the watermelon plants may want to take this free opportunity. As part of this project, we will collect information about fertilizer and irrigation application, and approximate yield of the evaluating field from growers. Summarized results of this project will be shared at the next Southwest Indiana Vegetable and Melon Growers[Read More…]