Research report from OSU's North Willamette Agricultural Research and Extension Center
Delbert Hemphill
OSU Dept of Horticulture, NWREC
The 1980-81 planting date trial involved the variety Armado April. The trials were seeded on July 25, August 2, and August 15 and transplanted on September 5, 11, and 17, 1980, respectively. In the 1981-82 planting date trial, Morse's March, Armado April, and Vision were seeded on July 15, July 30, and August 14, and transplanted on August 21, September 2, and September 21, 1981, respectively. Spring N applications were the same as for the variety trials (above).
In 1980-81, a 12-day range in transplant date had no significant effect on yield or harvest date (Table 8). The previous planting date trials had indicated a greater effect of planting date on mean head weight.
The effect of transplant date on yield and quality of three varieties in 1981-82 is seen in Table 9. In contrast to 1980-81, but in agreement with earlier trials, mean head weight and gross yield of all three varieties declined with later dates. However, winterkill of the very early variety Morse's March was greater with the earlier plantings, confirming results obtained in 1979. Curd of Morse's March suffered freeze damage, particularly with the first planting. A one-month spread in seeding and transplant dates led to a 19-day spread in peak harvest for Morse's March, but had little or no influence on peak harvest of Armado April or Vision. However, planting date did affect first harvest of Armado April.
These trials support the previous conclusion that a range of cultivars is a more effective means of spreading the harvest period than is a succession of plantings of one variety.
Table 8. Effect of planting date on yield and harvest period of Armado April, 1980-81 Transplant Mean head weight Harvest range Estimated gross yield date (pounds) First Peak Last (tons/acre)_____ 9/05/80 1.46 3/23 4/01 4/13 7.1 9/11 1.44 3/16 4/06 4/10 7.0 9/17 1.37 3/16 4/01 4/10 6.6 Table 9. Effect of planting date on yield, grade, and winter mortality of three winter cauliflower varieties, 1981-82 Trans- Mean Est. Yield plant Harvest range head gross of #1 Winter- Mean Variety date First Peak Last weight yield heads kill grade pounds --tons/acre-- % Morse's March 8/21 8/21 3/10 3/29 1.22 1.5 0.0 50 2.0Z 9/12 3/16 3/16 4/02 0.52 1.6 0.4 31 1.8 9/21 3/19 3/29 3/29 0.35 1.0 0.2 13 1.9 Armado April 8/21 3/19 4/13 4/16 1.35 5.7 5.4 13 1.1 9/12 4/02 4/13 4/23 1.08 4.6 2.9 0 1.4 9/21 4/13 4/16 4/26 0.85 2.6 1.2 19 1.6 Vision 8/21 5/21 5/25 5/25 2.01 15.2 5.8 6 1.7 9/12 5/25 5/25 5/28 1.98 11.1 2.6 0 1.8 9/21 5/21 5/25 5/28 1.52 5.5 1.9 0 1.7 ZFreeze-damaged curds on early maturing heads.