Realizing the potential of high tunnel tomato production and income in southern New England

Realizing the potential of high tunnel tomato production and income in southern New England

Summary

A high-tunnel trial of 13 tomato varieties and a production practice demonstration was carried out during the 2013 growing season at the University of Rhode Island and on the farms of four participating growers.  Per-plant yields and tissue nutrient levels were measured at the university trial, and grower-participants kept track of yields, quality, and their personal experiences with these varieties. Growers in Southern New England were invited to a twilight meeting on August 7 to observe the trial, taste the varieties, and learn about an intensive trellising system. An additional meeting was held on November 14 which featured a presentation by Richard McAvoy of the University of Connecticut on greenhouse tomato production and a presentation by the PI on high tunnel tomato production which featured highlights of the Partnership Grant project. In-person surveys with the growers were conducted in December to gain insight into high-tunnel tomato production issues as well as their experiences with these particular varieties. Video footage featuring the PI was shot in September for instructional purposes and is currently being edited into two 15 minute pieces, one featuring the varieties, and the other presenting and discussing the advantages of the intensive production techniques.

Objectives/Performance Targets

For the grower trial, farm visits were made to all growers, biweekly, starting in early May and continuing until early September.  Progress was documented through interviewing and photography.  Monitoring of plantings was documented through visual inspections, rather than direct measurements, for the sake of convenience.  Growers kept track of their own harvest weights and have supplied that information in three of four cases.  Tissue nutrient status was assessed visually, using the URI trial, which did have tissue nutrients measured twice, as a comparative reference. This was possible since nothing particularly abnormal appeared in three of the four growers’ tunnels. One grower’s trial was strongly underfertilized, with N, K and Mg deficiencies readily apparent. This grower had to be excluded from the trial in August as a result of not fulfilling expectations for his participation.

For the University of Rhode Island trial, plants were grown and monitored for per plant yield and leaf tissue nutrient content.  Tissue was sampled only twice since plants remained in excellent health until freeze-up, which occurred October 25. Vine length was sampled at the end of the season. The only disease worthy of documentation was powdery mildew, which didn’t appear until the end of August and was effectively held in check to the end.

Thirty-eight people attended a twilight meeting held at the URI Agronomy Research Farm on August 7, 2013.  The main feature was a tour of the high tunnels involved in the tomato trial, with a tomato tasting and trellising demonstration by the PI. Thirty more people attended an indoor meeting at the URI Turf Research building on November 14, which featured a presentation by Richard McAvoy of the University of Connecticut on greenhouse tomato production and a presentation by the PI on high tunnel tomato production which featured highlights of the Partnership Grant project. Currently, two video pieces are being edited which will feature 1) the varieties used in the trial and 2) the intensive production methods. When ready, notice will be sent out to a regional listserv with links to URI’s Youtube channel where the videos will be archived.

Accomplishments/Milestones

• Seedlings were started on February 1, 2013, by Harry and Sam Chase, Portsmouth, RI.
• During March and into early April, metal conduit pipes were suspended from greenhouse arches to serve as trellis support.
• Soils were sampled during the third week of March and results received April 12.
• Soil was amended accordingly with compost, lime and other amendments during this time period.
• Transplants were received and distributed to participating growers on April 15 and 16.
• Planting took place on April 18 and 19 at URI into 16°C soil. Hoops and row covers were installed to protect against cold night temperature, which which was -3°C on the night of April 20-21. Plants were undamaged.
• Grower-partners transplanted on their farms within one week of receiving plants, with the exception of one, which did not finish planting until the first few days of May due to an existing high tunnel crop of salad greens.
• Drip irrigation was installed on April 22
• Sideshoot pruning was started on April 29 and constantly maintained until mid October.
• Trellis strings were attached to plants and overhead conduit on May 8 at URI.
• First of season-long fertigation began on May 17.
• The first round of farm visits began the week of May 13 and continued biweekly until mid September.
• Plants at URI were hand weeded and hoed, then mulched with straw on May 23.
• Vine lengths were sampled for all varieties on May 30.
• The first lower (older) leaf pruning was done on June 7 and performed as needed throughout the season. Far greater amounts of leaf pruning were necessary during hot weather periods since vines needed to be lowered more frequently.
• First fruits began ripening (‘Sakura’) on June 7 at URI. Harvested yields were documented until October 25.
• First leaf tissue sampling on vigorously growing plants took place on June 12, and the second (and final) took place on July 8.
• First vine lowering took place on June 25 and was maintained as needed throughout the growing season. In extremely hot weather, lowering and pruning was done almost continuously to keep up with vigorous growth.  Some varieties were more vigorous than originally anticipated and had been planted on the sides of the structures where the ceilings were only 8 feet; the result was that lowering was required more often and during the earlier part of the season (until late July), ripening fruits ended up on top of the straw mulch rather than in the air.  As the season progressed, most ripening fruit was suspended in the air, resulting in higher quality fruit.
• Tissue sampling was not practical at participating growers’ farms because it had not been anticipated that the sample size was too small. Instead, samples were taken from URI plants and visual assessments for nutrient deficiencies were made throughout the season.
• A twilight meeting, attended by thirty-eight people, was held at the URI Agronomy Research Farm on August 12.  Another thirty people attended a meeting at the URI Turf Research building on November 14, which featured greenhouse and high tunnel tomato production presentations.
• Because of less-than hoped-for meeting attendance, video footage of discussion and demonstration inside the tunnels was shot in early September for creation of two pieces, one on intensive high tunnel tomato crop management, and the other on the variety trial itself.  Both pieces are currently being edited and will be available for viewing on URI’s Youtube channel by mid January.
• Disease rating was done for the first time in mid August when the first incidence of powdery mildew was observed. It is unknown as to whether discrepancies between varieties were due to susceptibility or to proximity to open ventilation areas. In particular, plants in the center tunnel rows situated underneath the roof vents seemed to have noticeably more disease than side rows.
• Vines froze on October 25, laden with fruit.  Vines were removed and soil within rows and in tunnel aisles was sampled.
• In late November and early December, the three remaining growers were surveyed and interviewed. Results and selected commentary will be included in the final report.

Impacts and Contributions/Outcomes

While there is much information to be gleaned from this project, conclusions can be drawn from the URI study with support from the data in Tables 1 through 3.

Tables 1 and 2 depict macro- and micro- nutrient concentrations in tomato leaf tissue on two sample dates, June 12 and July 8.  Of the macronutrients, potassium (K) was consistently just below the lower limit for suggested concentration.  While the leaves themselves did not demonstrate any noticeable symptoms of K deficiency, several varieties of fruit showed internal white and green tissue, which is a known sign of K deficiency, particularly in concert with high daytime temperatures.  Heavy fruit load and vigorously growing plants in hot weather most likely made it difficult for plants to take up all of the K that was necessary.  Similar symptoms were seen at cooperating growers’ tunnels.  Boron and Manganese were also consistently below reference levels, but no known symptoms of their deficiencies were displayed and no attempt was made to correct them. But perhaps the most important outcome from tissue testing is that concentrations of all nutrients were found to be virtually the same across all classes and varieties, which indicates that no particular class needs to be preferentially fertilized over another. This is important for the small scale farmer’s high tunnel management scheme where it may be difficult to isolate drip lines of certain tomato classes from others because of different fertility requirements.

Table 3 shows various yield parameters and fruit bearing times for all varieties.  Overall, per-plant yields for several of the varieties were fairly high at URI, though none of the participating growers achieved these levels, most likely because of their multifaceted business plans.  At URI, plants could have been planted more densely but based on recent cropping history with tomatoes in those tunnels, density was left lower in order to insure lower disease incidence.

All of the growers were pleased by their customers’ appreciation for several of the featured varieties and all plan to incorporate 2 or 3 of these into their plans for the coming season.  All growers also appreciated the opportunity to discuss the varieties with the PI and compare their performance. All learned a great deal more about growing high tunnel tomatoes than they had in previous seasons.

• Table 1
• Table 2
• Table 3

Collaborators: