ECONOMICS OF GREENHOUSE TOMATO PRODUCTION IN THE RURAL NORTH CENTRAL U.S.

This study was conducted to examine the profitability of greenhouse tomato production during the winter months and to determine the physical and economic effects of providing supplemental light. Tomato (Lycopersicon esculentum cv. 'Sunny') plants were established on double row/bed spaced 30.5 cm between rows, 76.2 cm between beds, and 15.24 cm between plants on a sandy loam soil. A total of 1280 plants was established in a 321.4 m² poly greenhouse. Some plots were supplemented with a PL-94 MR fixture with 430 watts/bulb 4 hours daily and 14 hours on cloudy days. The greatest average yield of medium size fruits was 523 g/plant/week in plants under supplemental light as compared to the control. No statistical differences (P=0.05) were detected on the yield of large and small size tomato fruits between the control and plants treated with supplemental light. The data show that fruit production is enhanced by as much as 62% and the proportion of fruit that is graded medium or larger is increased from 62% to 71% by providing supplemental light. Winter production of greenhouse tomatoes normally resulted in returns of $43,661 annually. However, the use of supplemental light increased the returns to investment and management by about 49%, a benefit in this case of $21,477 annually.