Grafting hoophouse tomatoes for improved yields and profitability

View the project final report

• 2009 annual report

Commodities

• Vegetables: tomatoes

Practices

• Education and Training: extension, farmer to farmer, on-farm/ranch research, workshop
• Farm Business Management: budgets/cost and returns
• Pest Management: cultural control, mulching - plastic, sanitation
• Production Systems: organic agriculture

Hoophouses are used by more than 60% of the mixed vegetable farmers in Maine. Tomatoes are the most common and profitable vegetable crop grown in hoophouses by Maine vegetable farmers. Mixed vegetable growers are reluctant to grow crops other than tomatoes in hoophouses because of the high demand for tomatoes and the high prices consumers are willing to pay for the crop. The intensive cultivation of tomatoes in hoophouses has lead to a buildup in the level of soilborne pathogens. Additionally, hoophouse tomatoes are often challenged with foliar diseases such as grey mold or powdery mildew which are not common in open field production. Consequently, growers are selecting cultivars bred for greenhouse production which possess tolerance/resistance to many of these foliar pathogens but often have weak root systems unable to grow well in hoophouse soil. Grafting tomatoes onto vigorous rootstocks has been used to overcome a wide range of biotic and Abiotic problems limiting tomato production including soilborne diseases, salinity, waterlogged soils. Many growers are using grafted tomatoes to improve yields and quality but the technique is not widespread. We are proposing a solution involving: hands-on grower training, a research based critical evaluation of using grafted tomatoes, and an education program involving grower experience case studies.

Profitable tomato production in Maine and New England is difficult due, in large part, to the region’s cool, short growing season. Hoophouses are unheated greenhouse structures used to extend the growing season. These structure make it possible to plant earlier in the spring; they provide a more favorable environment for plant growth; and provide protection from early fall frosts. Hoophouses are generally considered to be non-permanent or even movable structures in which crops are grown directly in the soil. Vegetable growers in Maine make great use of these structures, with about 60% of the State’s mixed vegetable growers having at least one hoophouse. Almost any vegetable crop grown in Maine can be grown inside a hoophouse, however; most of the growers in the region have chosen to grow tomatoes in high tunnels or hoophouses.

Proposed solution

Tomatoes are the most common and profitable vegetable crop grown in hoophouses by Maine vegetable farmers. Mixed vegetable growers are reluctant to grow crops other than tomatoes in hoophouses because of the high demand for tomatoes and the high prices consumers are willing to pay for the crop. Many growers fail to create and implement crop rotation strategies for their hoophouses and consequently run into problems due to the buildup in the level of soilborne pathogens. Additionally, hoophouse tomatoes are often challenged with foliar diseases such as grey mold or powdery mildew which are not common in open field production. Consequently, growers are selecting cultivars bred for greenhouse production which possess tolerance/resistance to many of these foliar pathogens but often have weak root systems.

We are proposing a solution involving: hands-on grower training, a research based critical evaluation of using grafted tomatoes, and an education program involving grower experience case studies, and development of materials for presentation at meetings and through print and electronic media.

Specifically our objectives are the following:
1. Conduct a workshop for up to 30 hoophouse tomato growers. Provide the growers with up-to-date production information and hands on experience grafting tomatoes.
2. Provide 30 growers with 20 grafted tomato plants for production in their hoophouses. Track growers experiences using pre- and post-season evaluations and on-farm visits.
3. Conduct detailed comparison of un-grafted and grafted tomatoes in hoophouses located on two organic and two conventional farms.

Project methods:

Workshop component:
A grafting workshop will be held at University of Maine’s Highmoor farm as part of the MOFGA/UMCE hoophouse tomato growers meeting. At this meeting, 30 participants will be asked to complete pre-workshop questionnaires. Post growing season questionnaires will be completed at the end of the growing season. (Appendix A). Workshop participants will be taught how to graft tomato plants and will have the opportunity to graft 20 tomato plants to grow in hoophouses on their farm. Rootstock and scion plants will be grown at Highmoor Farm using certifiable organic practices. Each participating farm will be visited at least twice during the growing season to document how the crop is doing, and record the grower’s perceptions about the grafted plants. Final questionnaires will be completed on the last visit to each farm at the end of the growing season.

Research component:
In this part of the project we are interested in quantification of how grafted, self grafted and un-grafted tomatoes compare in terms of plant health, fruit quality and yield, and economic return. Replicated experiments will be conducted at Highmoor Farm, two organic farms, two conventional farms using two tomato cultivars (‘Trust’, ‘Big Beef’) commonly grown in Maine hoophouses and selected by the four participating farmers. The experiments will be conducted as split-plot design with three replicates using the tomato cultivar as the main plots: 1) Check treatment, un-grafted plants; 2) self grafted plants; 3) grafted onto ‘Maxifort’F1 rootstock. Treatment plots will consist of 5 plants. As fruit mature, our student harvest crew will make bi-weekly visits to each location to prune, trellis plants and make harvests. Harvested fruit will be graded by size and quality; cull fruit will be graded for the type and extent of the defect i.e. blossom end rot, cracking, sunburn, insect, etc. Harvested fruit will then be made available for sale by the grower. Data will be collected on all costs and time associated for each treatment. Economic data will be used to create partial enterprise budgets for these methods of tomato production. Yields will then be statistically analyzed to compare the grafting treatments.

Project timetable:

January: Set date and make preliminary announcement of Hoophouse tomato meeting.
February: Second announcement for Hoophouse tomato meeting
Start tomato rootstock and scion plants
April: Hoophouse tomato and grafting workshop
May: Deliver grafted tomato plants
Plant replicated grafted tomato experiments
June: Farm visits
Pruning and trellising of experiments
July - September: Farm visits
Pruning and trellising of experiments
Harvest, grading, data collection
Season end questionnaire
October: Data analysis, report writing

January 2011: Presentation of findings at Maine Agricultural Trades Show