Finding the best Overture® product and dose for a US lettuce grower
+4.6%
+8.0%
4
Trial Summary
A large US greenhouse lettuce grower ran four trials of Overture® in its commercial production between April 2025 and March 2026. Teen-leaf lettuce was grown in NFT gutters on peat, with thousands of plants per treatment group in each trial, and yield was measured as the fresh weight of whole gutters at harvest.
The first two trials compared Overture® A and Overture® B, each applied once in the seeding spray at sowing. In the first trial the microbes went in through the main seeding tank, so the Overture® B rate could only be estimated, at about half the standard rate; later trials used a dedicated dosing tank. The grower then took Overture® B forward on its own, testing four rates from one-hundredth to ten times the standard rate to find the best dose.
Conclusions
Overture® B performed better than Overture® A in this grower’s trials. In the first trial, Overture® B increased gutter yield by +8.0% against +2.5% for Overture® A. In the second, hand-weighed heads were +8.6% heavier with Overture® B and +2.0% heavier with Overture® A.
The dose trials showed that more is not better. Overture® B gave +4.1% at one-hundredth and +4.6% at one-tenth of the standard rate, against +1.0% at the standard rate and −1.5% at ten times the standard rate.
For growers, this means the best result can come from a lower rate. It is why we work with each grower to fine-tune the dose for their own system.
Figures are corrected for harvest-order effects, as discussed with the grower’s R&D team.
