ASHS 2015 Annual Conference

Fresh market tomatoes grown in the soil in high tunnels (unheated greenhouses) are typically supported in order to improve yield and quality and make management easier. A variety of support systems are used but data on yield and quality of fruit from various systems is not readily available. We conducted trials in 2013 and 2014 in two high tunnels in Wanatah, IN, to compare yield of three tomato varieties grown using two support systems: stake and weave (W), or prune and string (S). Rows were spaced 4 ft apart with plants 2 ft apart in the row. In the stake and weave system plants were not pruned; stakes were placed every two plants, and string woven horizontally along either side of the plants along the row. In the prune and string system, indeterminate varieties Big Beef (BB) and Cherokee Purple (CP) were pruned to two main stems and each stem clipped to a vertical string. For the determinate variety Mountain Fresh (MF) one branch just below the first main stem flower cluster and all branches above that cluster were left to grow, but all branches below the first cluster were pruned off. Initially 2 and later up to 4 or 5 stems per plant on MF were clipped to vertical strings. Each variety was treated as a separate experiment for analysis. Yield of marketable fruit was significantly greater with W than with S support system: BB averaged 15.3 and 6.5; CP averaged  6.8 and 1.4, and MF averaged 17.3 and 14.8 lb plant^-1 for W and S, respectively. The percentage of total yield that was culled was less with W than with S for BB and CP, but not for MF: BB averaged 16.2 and 27.3, CP averaged 31.6 and 51.3, and MF averaged 13.8 and 13.3 percent cull by weight, for W and S, respectively. These results indicate that the stake and weave support system is likely to lead to greater marketable yield and a lower percentage of culls than pruning to two or several stems and clipping each stem to a vertical string.