Lap Farm — Small-space indoor farming: growing | lapfarm.com
A 60 x 30 cm shelf section holds 2-4 trays, and one 20-40 W LED bar on a 14-16 h timer lights them all.
Sizing starts from the shelf, not the lamp. One shelf section of 60 x 30 cm holds 2-4 standard 1020 trays (each 25 x 50 cm) with enough elbow room to water without lifting the whole row.
Over that section hangs one LED bar of 20-40 W. That wattage covers the full tray count on the section; you do not need a bar per tray, and squeezing a fifth tray under the same bar shows up immediately as leggy, leaning stems on the outer edge.
On narrow screens, swipe or scroll the plate sideways.
Photoperiod does the rest: put the bar on a timer for 14-16 hours a day. Consistency beats intensity here — a modest bar on a reliable timer outgrows a stronger light that gets switched by memory.
Scaling is by sections, not by crowding. Two sections mean two bars and 4-8 trays; daily watering scales with tray count at 200-500 ml per tray, so a full two-section shelf can drink 1.6-4 L a day at the top end.
The crops that fill those trays are covered in /microgreens-tray-setup, and the one crop that ignores shelf math entirely — the sprouting jar — is on /sprouting-schedule.
Further reading