Published in HortScience, Volume 34, Issue 5, September 1, 1999, pages 848-851.
NOTE: At the time of publication, the author Lauren Garner was not yet affiliated with Cal Poly.
Excessive stem elongation reduces plant survival in the field and hinders mechanical transplanting. Mechanical conditioning is an effective method for reducing stem elongation during transplant production. This investigation examined the consequences of mechanical conditioning, using brushing and impedance, on subsequent field performance of tomatoes (Lycopersicon esculentum Mill.). Mechanically conditioned transplants of processing tomatoes resumed growth after transplant shock as quickly as did untreated plants, and subsequent canopy development was also equal. In 4 years of field trials, yield was not reduced by mechanical conditioning. Transplants for fresh-market tomatoes may be more sensitive to injury than those for processing tomatoes because they flower sooner after the conditioning treatments. Nevertheless, neither earliness nor defects in the fruits of the first cluster were affected by mechanical conditioning. Early and total yields were equal in both years that fresh-market crops were tested. Thus, there were no adverse effects on field performance of either processing or fresh-market tomatoes as a result of reducing stem elongation by mechanical conditioning before transplanting. Improved wind tolerance was tested both in a wind tunnel and in the field. In wind-tunnel tests, brushed and impeded plants resisted stem bending at wind speeds 4 to 12 km·h–1 higher than did untreated plants. A 70 km·h–1 wind after transplanting killed 12% of untreated plants but only 2% of treated plants. Mechanical conditioning with brushing and impedance produced transplants with desirable qualities without adverse effects on field performance.