G. Miyao, M. Le Strange, M. Murray
California growers of processing tomatoes have long understood that a desirable target for a direct-seeded stand is multiple plants in a clump. Field studies have consistently demonstrated slightly higher yield with multiple-plant compared to single-plant configured stands. Before the development of vacuum planters, mechanical plate planters could commonly only deliver 2 to 4 seeds in a clump. The practice of multi-seeding was horticulturally advantageous as well as practical. In 1990, a few growers began switching to transplants as a response to increased seed and labor prices. Today, in California, an estimated 70% of the 113,000 hectares of canning tomato are transplanted. While the transplant industry examined multiple plants per cell, the practice did not become the norm. In 2002, applied field research in Colusa County indicated a benefit from multiple plants per plug. In 2004, testing at UC West Side Research and Extension Center in Fresno County supported the Colusa findings. Plug population density studies were also conducted in Yolo County. The earliest study in Colusa, demonstrated substantial yield gains of 9 to 15% when planting 2 or 3 plants per plug (117 t/ha was the baseline with single plants). As further tests were conducted, the results were both encouraging and substantial. However, the results were also mixed, both within and as well among locations.
Miyao, G., Le Strange, M. and Murray, M. (2008). MULTIPLE PLANTS PER TRANSPLANT PLUG IN PROCESSING TOMATOES: IS THERE A BENEFIT?. Acta Hortic. 782, 171-176
DOI: 10.17660/ActaHortic.2008.782.19
Lycopersicon esculentum, quality, yield, stand establishment, California

Acta Horticulturae