Growing microgreens is a rewarding and straightforward process. Even the simplest projects can have a few hiccups along the way. If your greens aren’t thriving or you’re noticing mold, uneven growth, or other issues, you’re not alone. Experienced growers experience these mistakes, too. With just a few adjustments, you can fix most problems easily. In this post, we’ll cover the most common pitfalls, like overcrowding seeds, overwatering, and insufficient light. Hopefully these tips will help you before you make them.
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Growing Microgreens Series
Overcrowding Seeds
The Problem:
Overlapping seeds lead to poor air circulation, mold, and uneven growth.
Easy Fix:
Spread seeds evenly across the tray, ensuring each has enough room to grow.
- Tip: Use a shaker or mix seeds with fine sand for even distribution. The next time you finish a large pepper shaker, or parmesan cheese container, save it, wash it out thoroughly, and use that as a seed shaker. You can also buy a shaker for cheap.
Overwatering or Underwatering
The Problem:
Overwatering causes mold and root rot, while underwatering stunts growth.
Easy Fix:
Use a spray bottle to mist the soil evenly.
Test moisture levels daily; the soil should be damp, not soggy. No device is necessary, just a finger test should be sufficient.
Ensure trays have proper drainage to prevent water pooling. This won’t be a problem if you water correctly with a spray bottle mister.
Insufficient Light
The Problem:
Without enough light, microgreens become leggy and pale.
Easy Fix:
Place trays in a bright location with 12–16 hours of indirect sunlight or use a full-spectrum grow light.
Keep the light 2–4 inches above the greens for optimal growth.
Mold and Mildew
The Problem:
Mold thrives in crowded, damp, and poorly ventilated conditions.
Easy Fix:
Provide good airflow with a small fan near the trays.
Use proper seed spacing and avoid overwatering.
Sprinkle a light layer of cinnamon (a natural antifungal) on the soil. Also: soak your seeds in a solution of 3% hydrogen peroxide before sowing.
Poor Germination
The Problem:
Seeds fail to sprout or germinate unevenly.
Easy Fix:
Use fresh, high-quality seeds labeled for microgreens or sprouting.
Pre-soak hard seeds like peas or sunflowers to boost germination rates.
Keep the tray covered during the germination phase to retain moisture and warmth. Another reason for poor germination could be overseeding.
Harvesting Too Late
The Problem:
Waiting too long to harvest your microgreens results in tough stems and diminished flavor.
Easy Fix:
Harvest microgreens when they’re 1–3 inches tall, typically 7–14 days after planting.
Using the Wrong Seeds
The Problem:
Certain seeds (e.g., nightshades, aka tomato) are toxic or unsuitable for microgreens.
Easy Fix:
Stick to recommended seeds like sunflower, radish, broccoli, alfalfa, and peas. Always research or buy seeds labeled for microgreens.
Improper Storage After Harvest
The Problem:
Greens wilt or spoil quickly due to poor storage.
Easy Fix:
Gently dry harvested greens and store them in an airtight container lined with a paper towel.
Keep them in the refrigerator and consume them within 7 days of harvesting.
Bonus Tips for Success
Stagger planting trays for a continuous harvest. Sow a tray of one microgreens seeds every week.
Experiment with different varieties to find your favorites. Microgreens come in very mild, to nutty, to peppery, to bitter flavors.
Clean trays and tools thoroughly between plantings to prevent contamination. Use hydrogen peroxide: it’s not harmful to plants, as the extra oxygen atom will evaporate.
