PRECISION AUTOMATION
Smart lettuce thinning: precision, labor, and crop performance
Evaluating edge AI-powered laser and spray technologies to remove doubles, reduce hand labor, and improve lettuce establishment.
Why thinning still matters
For Central Coast lettuce growers, successful thinning means establishing a uniform stand while protecting the plants that will reach harvest. Rising labor costs and limited crew availability make automated thinning increasingly attractive—but the value of a machine depends on how much follow-up work it actually eliminates.
Precision spray thinners use computer vision to identify seedlings and selectively apply concentrated fertilizer or herbicide to unwanted plants. To protect a selected “keeper,” the equipment leaves an unsprayed safety buffer. When two seedlings emerge close together, both may survive within that buffer. These doubles still require hand removal, along with any remaining weeds.
Laser systems offer a different approach: targeting unwanted plants with concentrated thermal energy. Their potential to remove closely spaced seedlings must be evaluated alongside accuracy, crop injury, operating speed, and cost.
What we are evaluating
Initiated in 2026, this project compares smart thinning technologies under commercial lettuce production conditions, including systems from Mantis Ag Technology, Carbon Robotics, and Vision Robotics. The evaluation connects machine performance with the labor and agronomic outcomes that matter to growers.
- Double removal: Measure how effectively each system removes unwanted seedlings and how many doubles remain after treatment.
- Cleanup labor: Record follow-up crew hours and costs per acre for removing doubles and residual weeds.
- Crop performance: Track keeper-plant injury, establishment, and final marketable yield.
- Operating conditions: Examine how bed flatness, soil tilth, seeding depth, in-row spacing, and travel speed affect performance.
- Treatment timing: Identify crop growth stages and environmental conditions that support effective thinning without stunting keeper plants.
From machine performance to farm economics
A high purchase price can be justified only if the benefits hold up in practice. Preliminary cost-benefit and return-on-investment analyses will bring together equipment capital costs, field operating speeds, cleanup labor, and marketable yield. Historical UC Davis cost benchmarks will provide context for those comparisons.
The aim is to identify the conditions under which each approach offers value, and the field preparation and management practices needed to achieve it. Results will support practical technology decisions rather than a single recommendation for every operation.