Indoor Microgreens: Fast Winter Nutrition in Small Spaces

By Sophia Martinez · October 12, 2026

What Are Microgreens and Why Grow Them in Winter?

Microgreens are young vegetable greens harvested 7-21 days after germination, when the first true leaves (cotyledons plus one set of true leaves) have developed. Research published in the Journal of Agricultural and Food Chemistry found that microgreens contain 4-40 times more nutrients than their mature counterparts, making them one of the most nutrient-dense foods you can grow.

Nutritional Profile

Key findings from USDA research:

Red cabbage microgreens: 6x more vitamin C, 40x more vitamin E, and 69x more vitamin K than mature red cabbage
Cilantro microgreens: 3x more beta-carotene than mature cilantro
Garnet amaranth: Highest vitamin K content among studied microgreens
Green daikon radish: Highest vitamin C concentration per gram

Equipment Needed

The barrier to entry is remarkably low. You need: shallow trays (10x20 inches, with and without drain holes), a growing medium (coconut coir or hemp mats work better than soil for indoor growing), seeds specifically sold for microgreen production (untreated, food-safe), a spray bottle, and a light source. A standard T5 or LED grow light 6-12 inches above the tray is sufficient.

Fastest-Growing Varieties

Radish: 5-7 days from seed to harvest. Spicy, peppery flavor. The fastest and most forgiving variety for beginners.
Broccoli: 7-10 days. Mild, slightly nutty flavor. Extremely high in sulforaphane, a compound studied for cancer-preventive properties.
Pea shoots: 10-14 days. Sweet, fresh pea flavor. Can be harvested twice if cut above the first node.
Sunflower: 10-12 days. Nutty, crunchy texture. Requires hulled seeds for best germination. Remove hulls from seedlings if they stick.
Kale: 8-12 days. Mild brassica flavor. Rich in vitamins A, C, and K.

Growing Protocol

Soak seeds for 4-8 hours (larger seeds like peas and sunflower; skip soaking for small seeds like radish). Spread evenly on moistened growing medium at a density of approximately 10-12 seeds per square inch. Cover with a humidity dome for the first 3-4 days (blackout period to encourage stem elongation). Uncover and expose to light. Water from below by adding water to the bottom tray. Harvest with clean scissors just above the growing medium when true leaves appear.