Liz Maynard

Clinical Engagement Assistant Professor of Horticulture
Department of Horticulture and Landscape Architecture
Liz Maynard's website

85 articles by this author

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Vegetables such as this watermelon may become sunburned if lack of foliage cover exposes the fruit to excess sun and heat. (Photo by Dan Egel)

​Loss of foliage due to poor growing conditions or disease can cause fruit to be exposed to the sun. Hot temperatures and direct sunlight can lead to areas of the fruit that appear bleached or sunburned. Sunburned fruit may not be marketable. To reduce the probability sunburned fruit, every effort should be made to maintain foliage throughout the season. Early wet weather encouraged foliar disease and recent hot, dry weather may have restricted foliar development. Orienting vegetable plantings to minimize damage from the prevailing winds and providing windbreaks such as strips of rye or wheat may help to reduce sunburn. Several products are available that are labeled for use as a preventive for sunburn. These products may be broken into two groups: kaolin (clay) based products and calcium carbonated based products. Kaolin based products include Surround®. Some Surround® products are labeled for use as sunburn protection, while others are not. For example,[Read More…]


Magnesium deficiency in cantaloupe often occurs in high

​I have observed many fields of cantaloupes with magnesium deficiency or manganese toxicity. Watermelon plants may exhibit similar symptoms, but not as frequently as cantaloupe. Both disorders are related to acid (low pH) soils and usually occur in clusters in a field. Magnesium deficiency usually appears on sandy ridges and can be recognized by interveinal yellowing and death of tissues on older leaves (Figure 1). Manganese toxicity also first occurs on older leaves but appears in heavier or darker sands, often in low areas of the field. The diagnostic feature of manganese toxicity are the tiny pin-hole type lesions with yellow halos clustered between the veins (Figure 2). Leaves are best viewed when held up to the sun. These disorders can easily be confused with an infectious disease. In particular, magnesium deficiency has been confused with Alternaria leaf blight. Symptoms may seem to “spread” from areas of the lowest pH[Read More…]


QR code linking to registration for August 13 event.

​Pinney Purdue Vegetable Field Day and Sweet Corn Sampler. Thursday, August 13, 2015. 4:00 p.m. – 8:00 p.m. CDT. Pinney Purdue Ag Center, 11402 S. County Line Rd., Wanatah, IN. Plot tours include soil health management and disease suppressive soils, tomatoes and peppers in high tunnels, and sweet corn varieties. Private Applicator Recertification (PARP) Credit available. To register, visit http://tinyurl.com/no6tosr or contact Lori Jolly-Brown, ljollybr@purdue.edu, or 765-494-1296. Beginning Farmer Tours. Free farm tours and networking events sponsored by Purdue Extension and Local Growers Guild. For more information and to register contact the Purdue Extension Education Store at www.edustore.purdue.edu or 888-EXT-INFO. August 18: Redbud Farm, home of Caprini Creamery, Spiceland, IN. Breakfast, networking, lunch and tour. September 8: Growing Places Indy, Indianapolis, IN. Lunch, networking session, tour. Urban produce farm with raised beds, u-pick, and greenhouses. September 14: Morning Harvest, Palmyra and Hardinsburg, IN. Breakfast, networking session, lunch and tour. Developing[Read More…]


​Growers may be wondering whether to replant pumpkin fields where the stand is uneven due to excess moisture. Potential yield of the replants is one thing it would be good to know. We have data on yield of pumpkins direct-seeded or transplanted in mid-July in northern Indiana. The trials were no-till planted into a harvested wheat field. Pumpkins were harvested in mid to late October. Yield of direct-seeded pumpkins ranged from 0 to 0.6 tons per acre for 8 varieties in 2004, and from 2.6 to 6.4 tons per acre for 5 varieties in 2005. Yield of transplanted pumpkins ranged from 2 to 8 tons per acre for 8 varieties in 2004 and from 4.4 to 9 tons per acre for 5 varieties in 2005. For comparison, typical yields at this site for an early- to mid-June planting date with conventional tillage range from 10 to 25 tons per acre.[Read More…]


Sweet corn ready for sampling.

​Pinney Purdue Vegetable Field Day and Sweet Corn Sampler. Thursday, August 13, 2015. 4:00 p.m. – 8:00 p.m. CDT. Pinney Purdue Ag Center, 11402 S. County Line Rd., Wanatah, IN. Plot tours include soil health management and disease suppressive soils, tomatoes and peppers in high tunnels, and sweet corn varieties. To register, contact Lori Jolly-Brown, ljollybr@purdue.edu, or 765-494-1296.


​The Agricultural Marketing Service (AMS) at USDA publishes information about prices, supplies, movement, and quality of vegetables every business day. On Thursday, July 16, 2015, 2:00 to 3:00 p.m. Eastern Time, AMS will offer a webinar about the Fruit & Vegetable Market News, what information on organic crops is available, and how to use the Market News Portal. There is no cost, but participants should register in advance at http://bit.ly/FVWebinarMN071615. The market news reports have a wealth of information; I would encourage any grower not already aware of what is available to take a look at the Market News Portal https://www.marketnews.usda.gov/mnp/fv-home even if it is not possible to attend the webinar.


​Preparing for the 2015 Melon Season. Tuesday, June 30, 2015. 8:00 A.M. – 12:00 P.M. EDT. Oaktown Produce Depot, 13990 N. Old U.S. 41, Oaktown, IN. This program is designed primarily for cantaloupe and watermelon growers, although all produce growers are welcome to attend. The Indiana State Department of Health will be on hand to discuss current departmental activities. Purdue scientists will update growers on current research. Other topics relevant to produce harvesting and packing will be discussed. For more information, contact Scott Monroe, jsmonroe@purdue.edu, or 812-886-0198. Planning for Success: Food Safety Plan Writing – Using Templates and Other Resources. Wednesday, July 1, 2015. 12:00 P.M. – 1:00 P.M. EDT. To participate online, go to http://bit.ly/FSPlanWriting. To participate by audio only, call 888-854-1541. For more information contact Scott Monroe, jsmonroe@purdue.edu, or 812-886-0198. Southwest Purdue Agricultural Center Field Day. Thursday, July 9, 2015. Southwest Purdue Agricultural Center, 4369 N. Purdue Rd.,[Read More…]


​High rainfall amounts lead to loss of nitrogen from the soil. Sometimes the loss is great enough that a crop will benefit from additional nitrogen application. This article will describe how nitrogen is lost and factors to consider in deciding whether to apply extra nitrogen. There are two main ways nitrogen is lost from wet soils. Nitrogen is lost to the air by denitrification. Denitrification occurs in saturated soils when there is little oxygen in the soil. In the denitrification process, nitrate is broken down by bacteria to form oxygen and volatile nitrogen compounds including nitrous oxide and nitrogen gas. These volatile compounds move into the air and nitrogen is lost from the soil. Denitrification is common on heavier soils. In Indiana, saturated soils lose 4% to 5% of their nitrate nitrogen for each day they are saturated. Nitrogen is lost below the root zone of the crop by leaching.[Read More…]


Seven day observed precipitation (in.) ending June 23

​Much of the state has seen excessive rains in recent weeks (Fig. 1). When soils are saturated vegetable crops suffer. This article, slightly revised from its original publication date in July 2003, describes and explains problems that are likely to occur.   Vegetable crops become stressed in waterlogged soils. Aboveground wilting, yellowing and death of leaves, and epinasty, or downward curling of leaves and stems are all responses to what is happening to roots. If we had a window into the soil we would see roots stop growing and root tips die due to lack of oxygen. Wilting occurs because roots in waterlogged soil do not conduct water as well and lack of new root growth limits water uptake, while the aboveground portion of the plant may continue to grow for a time even after the root has stopped. The root system just cannot supply water fast enough to prevent wilting.[Read More…]


​”Planning for Success: Food Safety Plan Writing” began Thursday June 4 and will continue on June 18 and July 1. The program is offered via WebEx, or by phone for audio only. Each program includes a presentation followed by time for discussion and questions and answers. “The programs are designed so that growers can participate over a lunch hour and get answers to current questions they may have as they work through the plan writing process,” says Scott Monroe, Purdue Extension food safety educator and organizer of the series. The series schedule (all times noon to 1 p.m. EDT): June 4: “Written Food Safety Plan Basics.” June 9: “Policies, Procedures and Documentation.” June 18: “Food Safety Protocols – What’s Out There.” July 1: “Using Templates and Other Resources.”   To join the program, go to http://bit.ly/FSPlanWriting. To participate by audio only, call 888-854-1541.