Liz Maynard

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

103 articles by this author

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Getting seedlings off to a good start begins with a good growing medium for transplants. Growing media for organic production must meet the guidelines set out by the National Organic Standards Board, including not containing any synthetic substances (unless they have been approved for that use) or any prohibited materials. A number of products meet those criteria, and many of them are listed by the Organic Materials Review Institute (OMRI) to document that they meet the criteria. Last year, with funding from a USDA Specialty Crops Block Grant through the Indiana State Department of Agriculture, a group at Purdue began evaluating commercially-available, OMRI-listed growing media for vegetable transplant production (Table 1). Table 1. Growing media used in transplant production trials, 2018. Product Abbreviation Source Johnny’s 512 J512 Johnny’s Selected Seeds Morgan Composting 201 M201 Morgan Composting Penn Valley Potting Soil PENN Penn Valley Farms PromixMP Organik PMPO BFG Supply Seed[Read More…]

Vegetable growers will find information-packed sessions at the Indiana Hort Congress next February. A few of the featured topics are highlighted in this article. Visit to see the full schedule and register. Climate will be the focus on Tuesday afternoon in a session sponsored by the USDA Midwest Climate Hub, Midwestern Regional Climate Center, and Purdue Extension. Climatologists and production specialists will take a look at existing climate and weather tools useful for Indiana vegetable and fruit growers. They will also generate discussion on what kinds of information about climate and weather would make planning and production easier in future. They will take results of that discussion back to the ‘shop’ to help plan future work. This will be an excellent opportunity to get up-to-date information about climate AND to help shape what kind of climate information is available and how you can get it in the future. Bring[Read More…]

On April 17, 2018, Purdue University and Indiana University Bloomington teamed up to present a webinar about using high tunnels in Indiana. The recording is now available on the Purdue Extension Youtube channel at The 95-minute webinar introduces the upcoming High Tunnel Handbook for Indiana growers and summarizes key findings and recommendations from a recent study about high tunnel use in Indiana. Key points about winter production from a SARE partnership project wrap up the session.

Figure 1. Top left: old plastic viewed from inside High Tunnel 1. Top right: old plastic as it is being removed. Bottom left: old plastic on left and new plastic on right over a piece of lined paper. Bottom right: High Tunnel 1 with new plastic covering.

Have you ever wondered how much difference new plastic would make in terms of light getting to crops in a high tunnel? We replaced 6-year-old plastic on High Tunnel 1 at Pinney Purdue Ag Center last week. Figure 1 below shows the high tunnel before and after recovering, and pieces of the old and new plastic. We had a sensor measuring PAR (photosynthetically active radiation, light available for plant use in photosynthesis) in the structure, and a similar sensor in High Tunnel 2, which had new plastic in Dec., 2017. The Ag Center also has an automated weather station that measures solar radiation. Here is what these sensors showed us (Figure 1). Figure 2 shows the PAR readings throughout the day in the two high tunnels and solar radiation outside. High Tunnel 1 had the 6-year-old plastic. The plastic was removed on July 9. On July 7 and 8, before[Read More…]

Many pesticides for use on vegetables have varying rules for use in different states. This article will review the different classes of labels for pesticides and where to find labels online. The shorthand names for classes of labels come from the section of the Federal Insecticide, Fungicide, and Rodenticide Act that governs each class. National labels are called Section 3 labels. These labels are approved by EPA for uses throughout the country. The Master Label on file with the EPA includes all registered uses. The label on a marketed product often contains only a subset of those uses. Even with federal approval of a Section 3 label, in order to be sold and used in Indiana, the product must also be registered with the Office of the Indiana State Chemist. To find products that are registered in Indiana, visit the NPIRS public web site. Search by product name, EPA[Read More…]

The USDA lab out of Wooster, Ohio is interested in surveying Indiana sweet corn for virus. They are especially interested in sweet corn near johnsongrass, but other fields are ok too. If you are interested, please let me know or contact Mark Jones, USDA Agronomist,, (330) 202-3555 ext. 2837. Your participation would be pretty simple: one time when the corn is 15 to 30 inches tall you would collect ten leaf samples on a field transect and also a sample of any odd looking plants and mail them to the USDA lab for analysis. USDA would mail you a packet with sample bags and instructions and mailing materials. If you are interested, but would rather have someone else collect the samples, I can check with a local county Extension educator to see if they would be interested in collecting the samples. Thanks for considering this!

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Reports of vegetable trials from 2017 are published online in the Midwest Vegetable Trial Report for 2017.   There are reports of variety trials for green beans, cantaloupe/muskmelon, slicing and pickling cucumbers, ornamental corn, bell peppers in field and high tunnels russet potatoes, pumpkins, spinach in high tunnel, butternut squash in stripped-till rye, sweet corn, fresh market and saladette tomatoes, tomatoes in high tunnels, and watermelon. The trials were conducted in Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, and West Virginia. This and previous reports in the series are a good source of information on relative performance of vegetable varieties.      

Slides from presentations at the 2018 Illiana Vegetable Growers Symposium and many of the fresh market vegetable sessions at the 2018 Indiana Hort Congress are available online. Visit

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This article is my response to a grower’s question about lowering soil pH in a high tunnel. The soil test indicated pH of the soil in his high tunnel was 7.7. The high pH could be partially caused by alkaline water he used to use for irrigation. The grower has changed the water source, but high soil pH is still a concern. ‘I have soil sample from the high tunnels if I could have your input on them I would appreciate it. I am concerned with the pH, should I use sulfur to bring it down, if so, how much?’ Following is my response to the grower’s question. My response is mainly based on the publication ‘Lowering Soil pH for Horticulture Crops‘. Purdue Extension HO-241-W. We have a few choices to reduce soil pH. Adding elemental sulfur is one way to do it. If you want to reduce soil pH[Read More…]

The Indiana Vegetable Growers Association board is seeking board members for 3-year terms beginning at the annual meeting in February 2018. Members interested in serving, or with suggestions for potential members, should contact President John Young at or 5028 E. Landersdale Rd. Mooresville, IN 46158. For more information about the IVGA visit