The Economics of Indoor Microgreens Farming
Microgreens—young vegetable greens harvested just after the cotyledon leaves emerge with the first pair of true leaves—represent one of the highest-revenue crops per square foot in urban agriculture. With production cycles spanning only 7 to 14 days and requiring minimal outdoor land, a vertical indoor rack setup spanning 100 square feet can generate consistent weekly revenue by supplying culinary restaurants, upscale supermarkets, and health-conscious consumers.
Essential Equipment and Infrastructure Setup
Indoor microgreen cultivation requires strict environmental and sanitation control:
- Standard Shallow Trays: Utilize durable food-grade 1020 trays (10 inches by 20 inches, approximately 25 cm x 50 cm). Use slotted drainage trays stacked inside solid catch trays to enable bottom watering.
- Growing Medium: Fine-grade, sterile coco coir buffered with calcium nitrate or food-grade hemp/cellulose mats. Avoid garden topsoil, which harbors fungal spores that cause damping-off disease.
- Full-Spectrum LED Lighting: Install 6500K daylight LED strip lights or T5 fixtures delivering 150–200 µmol/m²/s of photosynthetically active radiation (PAR) on an 18-hour light / 6-hour dark schedule.
- Climate Control: Maintain room temperatures between 18°C and 22°C (64°F–72°F) and relative humidity between 45% and 55%. Continuous oscillating air fans are essential to prevent mold growth.
Step-by-Step Cultivation Workflow
- Soaking and Seed Weighing: Large seeds (sunflower, peas) require pre-soaking in aerated water for 8–12 hours. Small seeds (radish, broccoli, mustard, amaranth) are sown dry. Weigh seeds accurately to ensure optimal canopy density without overcrowding.
- Tray Seeding: Spread soaked coco coir evenly across the tray (2–3 cm depth), mist thoroughly with filtered water, and distribute seeds uniformly from edge to edge.
- Blackout and Weighted Germination: Stack planted trays 4 to 5 high with an empty tray and a 2.5 kg weight on top. Weight forces emerging roots downward into the substrate and strengthens hypocotyl stems. Keep in total darkness for 3 to 4 days.
- Light Exposure & Bottom Watering: When seedlings reach 2–3 cm in height and shed seed hulls, unstack and place under lights. Transition strictly to bottom watering by adding water to the bottom tray; foliar top watering increases mildew risk.
- Harvesting: Harvest when true leaves begin to appear using clean, sanitized stainless steel harvesting knives or electric scissors 1 cm above the soil line.
Commercial Unit Economics and Popular Varieties
| Variety |
Seed per 1020 Tray |
Growth Cycle |
Average Tray Yield |
| Radish (Rambo / Daikon) |
30 – 35 g |
6 – 8 Days |
350 – 450 g |
| Speckled Pea Shoots |
200 – 250 g |
9 – 12 Days |
450 – 600 g |
| Black Oil Sunflower |
120 – 140 g |
8 – 10 Days |
400 – 550 g |
| Broccoli (Calabrese) |
20 – 25 g |
8 – 10 Days |
250 – 350 g |
