Liz Maynard

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

64 articles by this author

Article List

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 jmyoungco@yahoo.com or 5028 E. Landersdale Rd. Mooresville, IN 46158. For more information about the IVGA visit ivga.org.


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 jmyoungco@yahoo.com or 5028 E. Landersdale Rd. Mooresville, IN 46158. For more information about the IVGA visit ivga.org.


Figure 2. Multi-leaf lettuces grown in a high tunnel (photo credit: Liz Maynard)

Winter farmers markets are becoming more and more popular. Lettuce is a primary type of vegetables grown for the market. As we are finishing up summer crops, it is a good time to learn and refresh knowledge about lettuce. This article discusses some of the basics of growing lettuce in high tunnels, as well as the lessons we learned from a trial conducted at Southwest Purdue Ag Center in fall 2016. Lettuce Types Lettuce has multiple morphological forms major types include crisphead (iceberg), butterhead (bibb), romaine (cos), Batavian (summer crisp), and multi-leaf lettuce (salanova). The first decision about growing lettuce is whether to harvest full-size heads of lettuce, or to harvest ‘baby-leaf’ lettuce (Figure 1). These harvest methods require very different production practices. Full-size heads are harvested one time as a single head of leaves. Baby-leaf lettuce is first harvested when single leaves reach about 4 to 5 inches, and[Read More…]


Figure 1. Yellowstriped armyworm on tomato leaf.

We are seeing small caterpillars feeding on tomato leaves in high tunnels at Pinney Purdue. The first sign may be feeding partially through the leaf, or ‘windowpane’ feeding, or small holes on the leaf. By turning the leaf over we find a yellowstriped armyworm or hornworm (Figures 1 and 2). In the morning, we find moths clustered along the hipboard at the top of the sidewall (Figure 3). See Rick Foster’s articles in this issue for information on control.  


thumbnail image

Dr. Steve Weller, professor and extension weed scientist in the Dept. of Horticulture and Landscape Architecture is retiring from Purdue. I’m sure many readers share the Purdue Vegetable Extension team’s appreciation for all the work he has done to help vegetable growers with weed management and wish him the best in life’s next adventures. Thanks from all of us, Steve! You will be missed.


thumbnail image

We are looking for sweet corn growers to participate in our 2017 Vegetable Field Day and Sweet Corn Tasting. Our field day on Aug. 15 at Pinney Purdue Ag Center in Wanatah, will feature tours of tomato production in moveable high tunnels, using both conventional and organic management systems. The event also will include walking tours of sweet corn and pumpkin variety trials, an overview of research findings about the opportunities available through high tunnels, and information about the NRCS program. Attendees will learn about managing pollinators; low-cost high tunnel structures for the home gardener; irrigation solutions; site and structure considerations for new high tunnel users; and finding, preserving, and preparing fresh produce. Private applicator recertification credits (PARP) are anticipated. This event includes a dinner and sweet corn variety tasting. If you would be willing to donate 2 ½ dozen ears of corn, please contact Lyndsay to arrange pick-up/drop-off arrangements. Lyndsay Ploehn, Purdue[Read More…]


Figure 1. Lettuce in high tunnel showing symptoms of lettuce drop caused by the fungus Sclerotinia sclerotiurum. Photo by Erin Bluhm.

Some of the red and green multi-leaf lettuce plants in Figure 1 are wilted and closer inspection reveals death and soft decay at the crown and well as freeze damage (Figure 2). Getting even closer as in Figure 3 we see white fuzzy mold and find hard black sclerotia 1/8 to ¼ inch across and up to ½ inch long at the base of the plants and in the soil. These sclerotia confirm that the plants have succumbed to white mold or lettuce drop caused by the fungus Sclerotinia sclerotiorum. The lettuce was transplanted in September or October 2016 and the photos taken in mid to late January. We continue to see more plants succumbing to the disease. Infection by this fungus begins when sclerotia buried in the soil produce small mushroom-like apothecia and spores from the apothecia land on susceptible plant tissue, germinate, and invade the plant. Sclerotia can[Read More…]




Figure 3. The fungus on this senescent female pumpkin flower (Choanephora sp.) is growing on a flower which did not develop properly.

There has been some concern about poor fruit set in pumpkin fields that otherwise have healthy vigorous vines. This summer we have experienced above normal temperatures for much of the pumpkin fruit set season and I suspect that has played a role. This article will consider temperature as well as other factors that influence pumpkin fruit set. In order for fruit set to take place, male and female flowers must be open on the same day, pollinating insects must be active, the plant must not be too stressed and it must have an adequate level of carbohydrates. Growers can influence some of these conditions. High temperatures promote death of female pumpkin flowers while still in the bud stage. Varieties differ in the their sensitivity to high temperatures. To determine whether flowers have died early in development requires close inspection of the pumpkin vine. An aborted bud often dries up and[Read More…]