In an attempt to confirm results obtained in 1979, the cultivars Armado April and Preminda (Royal Sluis Co.) were seeded on August 1, 16, and 30, 1979, and were transplanted on August 28, September 10, and October 8, respectively. Nitrogen rates, in addition to the base fertilizer at planting, were 1) 50 pounds N/acre sidedressed as ammonium nitrate on February 12 and again on March 7, 1980, and 2) 100 pounds N/acre on the same dates. Plots were 4 rows x 25 feet and treatments were in randomized block design.
Results are presented for the first two transplant dates (Table 3). The third planting made insufficient foliar growth before head formation. Yield and quality were judged too low to justify harvesting the plots. In contrast to 1979, there were significant interactions between variety and transplant date and between N rate and transplant date. Armado April significantly outyielded Preminda for the first planting date, but not at the second date. Increasing the N rate increased head size and yield of both varieties for the first, but not for the second, transplant date.
The first planting produced the highest yields, regardless of cultivar or N rate. Quality was also higher for the first planting. Nearly 80% of the heads of both varieties were judged acceptable for fresh market while only 65% of the heads from the second planting were marketable. In general, heads from the second planting were smaller, looser, and had more yellow pigmentation.
Rate of N again had no effect on quality or date of maturity, increasing head size only. Plants were not noticeably larger, nor the curd better protected, at the higher N rate.
Winterkill was not a factor in this trial, averaging less than 1 percent, and did not vary significantly with treatment.
Table 3. Effect of transplant date, variety, and N rate on overwinter cauliflower, 1980 Transplant N rate Total yield Mean Head Harvest Span date Variety (pounds/acre) (tons/acre) wt.(pounds) First Peak Last Aug. 28 A. April 100 6.9 1.77 4/07 4/14 4/21 200 9.6 2.06 4/01 4/14 4/21 Preminda 100 6.6 1.45 4/01 4/07 4/21 200 8.5 1.88 4/01 4/07 4/21 Sept. 10 A. April 100 5.5 1.15 4/14 4/14 4/21 200 5.9 1.21 4/07 4/14 4/21 Preminda 100 5.2 1.13 4/07 4/14 4/21 200 5.4 1.23 4/07 4/14 4/21 LSD(0.05) 0.9 0.34 Mean, first planting 7.9 1.79 4/04 4/11 4/21 second planting 5.5 1.18 4/08 4/14 4/21 **Z ** Mean, A. April 7.0 1.55 4/07 4/14 4/21 Preminda 6.4 1.42 4/04 4/11 4/21 NS NS Mean, 100 pounds N 6.1 1.38 4/07 4/12 4/21 200 pounds N 7.4 1.60 4/06 4/12 4/21 * * Z**, *, NS: means differ significantly at 1% level (**), 5% level (*), or do not differ significantly (NS).