In May 2004, we concluded the second year of the Noble Research Institute's hoop house strawberry trial.
The objective of this on-going trial is to evaluate the performance of commercial strawberry varieties grown in the growth-enhancing environment of a hoop house. Because growing conditions vary from year to year, a better indication of varietal performance can be achieved by testing over a several-year period. If a variety is clearly inferior, current plans are to remove it after two years. Most varieties will be trialed for three years.
To date, all of the varieties tested are short-day, June-bearing varieties commonly used in a plasticulture system. Varieties included in the 2004 trial that were part of the 2003 trial include Camarosa, Chandler, Sweet Charlie and JP4. Treasure was not included in the 2004 trial due to unavailability. Gaviota was dropped for 2004. Ventana and Festival were added to the 2004 trial for a total of six varieties.
On Oct. 1, 2003, three rows of transplants (produced from tip cuttings obtained from Canada) were set into each of four beds. Rows were spaced 12 inches apart with individual plants in each row spaced 16 inches apart. Each variety (treatment) was replicated four times with each of the four beds serving as a replication. Each treatment contained 72 plants, 18 per replication.
The hoop house remained fully vented from October through February to limit the amount of premature fruiting. Air temperature dropped to 11 degrees Fahrenheit in the early morning of Jan. 6. The house remained open and no floating covers were used for plant protection during this time.
Beginning March 1, vents were adjusted as needed to maintain a target temperature of 80 F for the purpose of forcing the crop.
Harvest began on March 26 and ended May 24. Results for marketable weight and berry size are reported in Table 1.
Ventana was the top-yielding cultivar (1.42 lbs./plant) in this year's trial, with JP4 coming in last place (0.72 lbs./plant). Among repeat entries, 2004 yields were lower with the exception of Camarosa. Berry size, however, tended to be a little larger in the 2004 trial.
The reduction in yield observed in this year's trial could have been temperature related. The extreme cold temperature recorded on Jan. 6 was preceded by several days of high temperatures in the 70s, so perhaps a small number of flower buds were killed as a result of the sudden drastic change in temperature. But the yield reduction could have been the result of a combination of factors.
As a general rule in southern Oklahoma, strawberry plants do not require protection during the winter months. Based on the extreme temperature fluctuations experienced this past winter, we've decided to play it safe by covering beds with heavy-weight row covers and closing up the house if a similar situation is forecast to occur in the future.
JP4 produced the largest berry both years. Although very large, the taste left a lot to be desired, based on in-house taste tests. The plant and fruit are also very susceptible to disease. Based on the poor performance of JP4, we've decided to drop it from the trial.
On a more positive note, Ventana was the surprise of this year's trial. This variety produces large, uniformly shaped, good-tasting fruit. We'll be sure to keep our eye on this variety in upcoming trials. Stay tuned for the results.