<b>Evaluating Strategies to Produce Compact Vegetable Plants and Identifying Gardening Preferences and Behaviors Using a Citizen-Science Approach</b>
Creators: name: Fidler, Michael David
Publisher: name: Purdue University Graduate School
Year: 2024
Subjects: classificationCode: 300802
subject: Horticultural crop growth and development
classificationCode: 520102
subject: Educational psychology

description: New cultivars of compact tomato (<i>Solanum lycopersicum</i>) and pepper (<i>Capsicum annuum</i>) plants are available to consumers, creating niche market opportunities for greenhouse growers who produce vegetable bedding plants for spring sale. However, production guidelines for these crops are limited. We conducted two experiments to evaluate non-chemical means of height control for these plants. In the first experiment, we treated ‘Siam’ tomato and ‘Basket of Fire’ pepper plants with 0, 50, 100, 150, or 200 mg·L<sup>–1</sup> nitrogen (N) during the “production” phase and used a similar or higher N concentration during the “fruiting” phase. Our results show that although height of these plants can be controlled with lower fertilizer concentration, their yield will likely be affected by limiting fertilizer availability. In addition, our findings suggest that these plants can be grown without the addition of fertilizer during production, provided that the substrate has a starter fertilizer charge, and that sufficient fertilizer is applied during the fruiting phase. In the second experiment, we characterized the effects of fertilizer use and substrate volumetric water content (VWC) during production using the same compact plants, and evaluated post-production carryover effects on growth and yield. Plants either received water-soluble fertilizer (100 mg·L<sup>–1</sup> N) once a week, or were irrigated with tap water only, relying on the starter fertilizer charge in the substrate. In addition, plants were irrigated when the substrate VWC reached 0.15, 0.30, 0.45, or 0.60 m<sup>3</sup>·m<sup>–3</sup>. Overall, our results show that substrate VWC had minimal effects on growth and yield, but plants that were not fertilized were shorter, had less biomass, and produced less fruit than those treated with fertilizer. These findings suggest that growth and yield of these compact tomato and pepper plants are affected to a larger extent by fertilizer use than by substrate VWC.In effort to better understand consumer preferences for these new compact plants, we used a citizen-science approach in another experiment. Approx. 300 participants from three states in the USA (IN, IA, and TN) compared three compact tomato cultivars (Red Robin, Cocoa, and Micro Tom) started from seed or as transplants. In addition, we compared pre- and post-experiment survey responses to assess potential changes in behaviors, beliefs, and attitudes towards gardening as a result of the experiment. Cocoa was the preferred cultivar, closely followed by Red Robin. Our results indicate participants valued plant appearance, fruit yield, and fruit taste when making these preference choices. Approximately 70% of participants preferred plants started as transplants compared to those from seed, regardless of cultivar. Most participants reported they would be willing to pay between $1.00 to $7.49 more for a transplant of their favorite cultivar compared to tomato plants available at local nurseries. Results for dietary behaviors show that participants increased their consumption frequency of fruit, lettuce salad, vegetables, and food mixed with vegetables at the end of the experiment, but few differences were measured for beliefs and attitudes towards gardening, likely due to previous positive biases towards gardening among project participants. In conclusion, results from our experiments show that growth and yield of compact tomato and pepper plants can be controlled by adjusting fertilizer management practices. In addition, citizen science was shown to be an effective research method to assess plant-performance and consumer-preference data, and to measure potential changes in behavior of project participants.