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
(812) 886-0198 guan40@purdue.edu
Wenjing Guan's website

185 articles by this author

Article List

Growing Grafted Cucumbers for Early Season Production in Protected Cultural Systems — Lessons Learned from on-farm Trials

October 24, 2018 - From Issue:
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Figure 1. Cucumbers were grown in a greenhouse in April 2018

Cucumbers are extremely sensitive to cold. Locally grown cucumbers are almost only available in the summer. While in Asia, without the use of fancy heated greenhouses, cucumbers can grow all winter. Growing grafted cucumbers with cold tolerant squash rootstock is one of the key factors making this possible. Since 2016, we started to evaluate opportunities of using grafted plants to extend early season cucumber production under protected cultural systems in the Midwest. We observed promising results in our research trials. However, knowing research trials can only tell part of the story, we initiated multiple on-farm trials across Indiana to better understand if and under what circumstances growers would benefit from this technique. This article discusses the lessons we have learned so far and raises questions that need to be answered. Heated greenhouses A pronounced advantage of using grafted cucumbers was observed in the situations that cucumbers were grown in soils[Read More…]

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Time to Renew

October 24, 2018 - From Issue:
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This is the final issue of the Vegetable Crops Hotline (VCH) for 2018. Subscribers who receive a paper copy in the mail need to renew. A renewal form is included with this issue. We are providing up-to a three years’ subscription of VCH at a reduced price (1 year for $15, 2 years for $25, and 3 years for $30). You can check the number on the right bottom corner of your VCH envelope to find what year your subscription will last through. You can 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[Read More…]

The 2019 North Central Region – Sustainable Agriculture Research & Education Grant Opportunities

September 20, 2018 - From Issue:

Farmer Rancher Program These grants are for farmers/ranchers to explore innovative sustainable agriculture solutions to production, marketing, labor, and other problems. There are three types of competitive grants: individual grants ($9,000 maximum), Team of Two grants for two farmers/ranchers from separate and distinct operations who are working together ($18,000 maximum), and Group grants for three or more farmers/ranchers from separate and distinct operations who are working together ($27,000 maximum). Projects may last up to 24 months. Interested applicants can find the call for proposals online as well as useful information for completing a proposal at https://www.northcentralsare.org/Grants/Our-Grant-Programs/Farmer-Rancher-Grant-Program. Proposals are due on December 6, 2018. Partnership Program The Partnership Grant program funded by the North Central Region Sustainable Agriculture Research and Education (NCR-SARE) program is intended to foster cooperation between agriculture professionals and small groups of farmers and ranchers to catalyze on-farm research, demonstration, and education activities related to sustainable agriculture.  Partnership Grants[Read More…]

Harvest and Postharvest Storage of Pumpkins and Winter Squash

September 20, 2018 - From Issue:
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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.). 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 of[Read More…]

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Upcoming Events

September 20, 2018 - From Issue:
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Produce Safety Alliance Grower Training Date: September 28, 2018, 9:00 am – 5:00 pm (EST) Location: Southwest Purdue Agriculture Center, 4369 N. Purdue Rd., Vincennes, IN Purdue Extension will be hosting a Produce Safety Alliance (PSA) Grower Training on September 28th. The training will be held in the basement of the SWPAP building at the Southwest Purdue Agricultural Center, 4369 N. Purdue Rd., Vincennes, IN 47591. This program meets the training requirements of the Food Safety Modernization Act Produce Safety Rule. Cost is $100 and covers course manual, completion certificate, and lunch. Register by going to www.SafeProduceIN.com and clicking on the “Get Trained” option. Participants must pre-register. Registration will be closed on 9/26/18. For more information, contact Scott Monroe at (812) 886-0198. Southwest Indiana Melon and Vegetable Growers’ Technical Meeting Date: November 15, 2018 5:00 pm to 8:00 pm (EST) Location: Southwest Purdue Ag Center (SWPAC), 4369 N. Purdue Road, Vincennes,[Read More…]

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Farm to School Survey

September 18, 2018 - From Issue:

Indiana State Department of Agriculture/Indiana Grown was recently awarded a grant in partnership with the Indiana State Department of Health, Indiana Dept of Education and Purdue Extension to create an all-inclusive local food sourcing guide for schools, called Indiana Grown for Schools: School Food Service Resource Guide. This two-year project will start with gathering information from Indiana farmers, producers and distributors then compiling it into a county by county guide that will be dispersed to all schools in the state of Indiana. If you want to have your information included in this guide, please fill out this survey https://goo.gl/forms/GFyrZrlUjxA0xZhx2 The deadline to fill out the survey is October 31, 2018. The survey also has some helpful links about Indiana food safety requirements – which may help those who are still unsure as to whether or not they qualify to sell to schools in Indiana. If you have any questions, please contact Heather Tallman at HTallman@isda.in.gov

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High Salinity Levels May Affect Tomato Production in High Tunnels

August 30, 2018 - From Issue:
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I visited a few high tunnels around the state recently and used a hand-held soil electrical conductivity (EC) meter to test soil salinity levels inside of the structures. Although the hand-held EC meter may not give ratings as accurate as a soil test lab could provide, I had comparative ratings from several farms. Interestingly, by talking to growers, I found tomatoes grown in the high tunnels that have relatively high EC ratings seem to suffer more problems in the past season. In most cases, the unhealthy plants have been taken out of the tunnels by the time I visited (in early August). In one situation, the farmer reported flower abortion and a lot of blossom end rot. In another situation, the farmer described a widespread leaf spot symptom that was not a disease. He followed the recommendation based on plant tissue analysis, but the problem was not solved. In the third situation, tomato[Read More…]

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Hollowheart of Watermelons

August 30, 2018 - From Issue:
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Figure 2. A severe case of hollowheart watermelon.

Hollowheart of watermelons is a physiological fruit disorder. Flesh separates inside of the fruit, typically forming three gaps (Figure 1 and 2). In severe cases, hollowheart could cause watermelon load rejection. Watermelon fruit that has hollowheart tends to be triangular shaped. Poor pollination is the primary reason causing hollowheart. Scientists were able to prove that seedless watermelons are more likely to develop hollowheart when the pollenizer plants (diploid watermelons) are located further away from the seedless plants. The study found hollowheart incidence starts to increase when the distance between the seedless plant and the pollenizer plant is more than 6 feet. Cold weather and the lack of bee movement during pollination period causes poor pollination and increases the chance of hollowheart. Some growers use mixed pollenizer plants with different flowering peaks to ensure availability of pollen matching the blooming period of seedless plants. Bumblebees, in addition to honeybees, are sometimes used; bumblebees are relatively more[Read More…]

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The 2019 North Central Region – Sustainable Agriculture Research & Education Grant Opportunities

August 30, 2018 - From Issue:

Farmer Rancher Program These grants are for farmers/ranchers to explore innovative sustainable agriculture solutions to production, marketing, labor, and other problems. There are three types of competitive grants: individual grants ($9,000 maximum), Team of Two grants for two farmers/ranchers from separate and distinct operations who are working together ($18,000 maximum), and Group grants for three or more farmers/ranchers from separate and distinct operations who are working together ($27,000 maximum). Projects may last up to 24 months. Interested applicants can find the call for proposals online as well as useful information for completing a proposal at https://www.northcentralsare.org/Grants/Our-Grant-Programs/Farmer-Rancher-Grant-Program. Proposals are due on December 6, 2018. Partnership Program The Partnership Grant program funded by the North Central Region Sustainable Agriculture Research and Education (NCR-SARE) program is intended to foster cooperation between agriculture professionals and small groups of farmers and ranchers to catalyze on-farm research, demonstration, and education activities related to sustainable agriculture.  Partnership Grants[Read More…]

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