Kozai's SLA Calculator

"SLA" (Specific Leaf Area) is how much leaf area a plant grows per gram of dry leaf weight — in other words, whether its leaves are thin and expansive or thick and dense. It is a classic plant-science indicator (Kozai popularized its use in controlled-environment production). A high SLA means thin, sprawling leaves typical of fast early growth or low light; a low SLA means thick, compact leaves typical of high light or mature/reproductive plants.

When you can destructively sample a few representative plants — you measure total leaf area (leaf-area meter or photo analysis) and then dry and weigh those leaves. Useful for research, propagation, and dialing in light levels across a crop's life. It works for most leafy and vegetable crops. It requires a scale and drying, so it is a periodic measurement, not a daily one.

The tool reports SLA in cm²/g and maps it to a growth stage. Very high SLA (>300) reads as early vegetative and suggests the canopy could take more light (raise intensity 10–15%); mid-range is on track; low SLA (<150) reads as mature/reproductive and suggests easing light or shifting toward far-red. Rising SLA over time can also warn that plants are stretching for light. Treat the light suggestion as a starting nudge — change intensity gradually and re-sample, since thresholds are general, not crop-specific.