A +6.6% green leaf lettuce yield gain at Greenswell Growers
+6.6%
24,585
2
Trial Summary
Greenswell Growers grow lettuce in open-channel gutters on peat in central Virginia, sowing five days a week and weighing every channel automatically at harvest. In two consecutive trials, Overture® B was injected into the water sprayed onto the seed at sowing.
To compare like with like, treated and untreated sowings alternated by half-day, swapping each day, so that treated and untreated channels grew side by side through the same weather. Trial 1 tested Overture® B at the 1X rate against the grower’s standard practice on their main variety, Danstar. Trial 2 then tested it on top of the grower’s standard biological product, at four rates from 1/100 to 10X the 1X rate. Each rate went on its own block of sowings, and 24,585 channels were weighed.
Conclusions
At its lowest rate, 1/100 of the 1X rate, Overture® B increased Danstar yield by +6.6% vs untreated channels in Trial 2. At the 1X rate it gave +3.9% in Trial 1 and +2.8% in Trial 2, and across all four rates Trial 2 averaged +1.6%. The 1/10 rate showed no gain (−0.2%), with a suspected technical issue. Red leaf gained at every rate, from +6.7% to +12.2%, though over fewer harvest days.
Because each rate went on its own block of sowings, the rates were also tested at different times of year. Every gain came on top of the biological product the grower already uses.
To compare like with like, each channel’s weight was converted to grams per day of growth and compared with untreated channels harvested on the same day (in Trial 2, also from the same line and cut height). At this scale, a gain of a few percent across the crop adds up to a meaningful amount of extra lettuce from the same glass.
