Plot size: Four rows/bed 7.5’ long x 6”apart – 60 plants/rep.Transplanting Date: April 29, 2004Production system: raised bed with IRT green plastic mulch and 2 rows of drip tape – high flow 0.45 gal./min./100 ft at 12 orifice spacing.Herbicide Application: One post-emergence applications of Goal at 3.0 oz./A.Fungicide: Two applications of Bravo at 2.5 pt./A.Insecticide: One application of Warrior at 3.0 oz./A.Fertility: Broadcast and incorporated 60 lbs./A-N, 60 lbs./A-P, and 120 lbs./A-K and two applications of calcium nitrate injected in the drip system for a total of 14 lbs./A N.

Harvest Date: August 18, 2003Drying: Bulbs from individual plots were placed in potato 100 lb. Burlap bags and placed on the Horticulture Farm greenhouse benches for 7 days.Date Graded: September 8, 2004

Design: Randomized Complete Block with 3 replications

Results:
Growing conditions in 2004 were less than ideal even for sweet Spanish onions grown on raised beds with plastic mulch and two rows of drip tape, but better than the 2003 growing season. It was fortunate to find a period of time in mid-April when the soil was dry enough to make beds and lay plastic mulch plus the drip tape. We were also fortunate in 2004 to be able to broadcast the 10-10-20 prior to making the raised beds with plastic mulch. Fourteen pounds of nitrogen was injected into the drip irrigation tape over a 7-8 week period after transplanting. Use of greenhouse grown plug plants helped to accelerate the transplanting of the onion varieties in 2004 compared to 2003. Transplanting the tray or greenhouse grown transplants was much quicker, efficient and uniform compared to the field grown transplants. While weed control was good to excellent the first 4 weeks after transplanting, continued rain resulted in significant weed populations (both grass and broadleaf weeds) in and between the onion rows. The single application of Goal and Poast significantly reduced weeds and increased harvesting efficiency.

The highest marketable onion bulb yield was obtained from Expression, EM 398, Hidalgo and Milaga compared to Candy (current sweet Spanish onion standard Table 1). The marketable yield of Eagle was slightly lower than Candy, but has a larger average bulb size and higher soluble solids level than Candy (Tables 1 and 2). Expression produced 80.5% of bulbs that were 3.0 in diameter or larger that was similar to Candy. Both Robin and Red Beauty had a higher percentage of double centers compared to BGS 178 and overall appearance of the red onion varieties was best exemplified by the variety BGS 178.

Table 1. The marketable yield of fourteen onion varieties evaluated at the Horticulture Research Farm, Rock Springs, PA – 2004.

Table 2. The size distribution and soluble solids of fourteen onion varieties evaluated at the Horticulture Research Farm, Rock Springs, PA – 2004.