The 2012 ASHS Annual Conference

Studies was conducted over 2010 to 2012 assess the productivity of different cool season leafy green crops under high tunnel culture at 4 locations across the central and eastern region of Oklahoma.  The objective was to determine the feasibility of small scale commercial production during fall, winter and spring.  The four locations were Ardmore, Lane, Oklahoma City and Tulsa.  Each site used high tunnels covered by a single layer of clear polyethylene film.  Nine different cool season greens were included: spinach, Swiss chard, romaine lettuce, collard, kale, mustard, spinach mustard (mild type mustard), turnip and broccoli raab (2010–2011) or leaf lettuce (2011–2012).  Raised soil beds were utilized at three sites and planting was on-grade at the 4^th location.  Soils at all sites were prepared for planting by soil testing to determine the levels of nitrogen, potassium, and phosphorus and soil pH.  Fertility levels were targeted at 120 lbs. of nitrogen and 150 lbs. per acre for each of phosphorus and potassium.  Plots were direct seeded in late September and early October with hand push precision planters using rows spaced 4.5 inches apart and approximately 8 to 9 seeds/linear foot.  In the 2011–2012 trial lettuce was established using transplants.  Crops that bolted were replanted in some cases.  Treatments were randomized with either 3 or 4 replications per site.  Harvest began late in October and continued through June.  The winter of 2010–2011 can be described as being colder than normal for the region (January and February) while the following winter was milder than normal.  Comparisons will be made of performance of specific greens crops across the two seasons of trials.  Trial results may be viewed in MP-164 “Vegetable Trial Report” at:  http://www.hortla.okstate.edu/industry/vegetables/pdf/11vegreport.pdf