Microgreens are relatively easy to grow, but they can face several issues that affect their growth, quality, and yield. Below are some of the most common problems and how to fix them.
1. Mold and Fungal Growth
Symptoms:
- White, fuzzy mold on the soil or stems
- A damp, musty smell
- Weak, falling-over seedlings
Poor air circulation High humidity or excessive moisture Overcrowding of seedsSolutions:
Improve air circulation (use a small fan) Reduce humidity (keep it around 40–60%) Water at the base instead of overhead spraying Space seeds evenly to prevent overcrowding Use food-grade hydrogen peroxide (1% solution) to kill mold
Tip: A small fan running near your microgreens will help prevent mold growth.2. Poor or Uneven Germination
Symptoms:
- Seeds are not sprouting evenly
- Patchy or thin growth
Uneven seed distribution Poor seed quality or old seeds Incorrect temperature for germinationSolutions:
Soak large seeds (peas, sunflowers) for 8–12 hours before planting Maintain 65–75°F (18–24°C) during germination Use fresh, high-quality seeds with good germination rates Spread seeds evenly across the tray Tip: Press seeds lightly into the growing medium for better contact and sprouting.3. Leggy and Weak Stems
Symptoms:
- Tall, thin, and weak microgreens
- Falling over instead of standing upright
Not enough light Lights placed too far away Overcrowded traysSolutions:
Use full-spectrum LED grow lights Keep lights 4–6 inches above the plants Give microgreens 12–16 hours of light per day Avoid over-seeding, which causes competition for light Tip: Rotate trays daily to ensure even exposure to light.4. Yellowing Leaves
Symptoms:
- Leaves turn yellow instead of staying green
Lack of light Overwatering leading to root rot Nutrient deficiency (rare in microgreens)Solutions:
Ensure 12–16 hours of light daily Reduce watering and improve drainage If using a hydroponic system, add a mild nutrient solution Tip: If microgreens look pale before exposure to light, it's normal! They green up quickly under proper lighting.5. Overwatering and Root Rot
Symptoms:
- Mushy stems and wilting
- Foul smell from the roots
- Brown, slimy roots
Watering too often or too much Poor drainage in trays Stagnant water in the growing mediumSolutions:
Water only when the surface feels dry Use a draining tray to prevent water buildup Water from the bottom by placing trays in a shallow water bath Tip: A fine mist sprayer can help control moisture levels without soaking the soil.6. Pests (Gnats, Aphids, and Mites)
Symptoms:
- Tiny flies (fungus gnats) flying around
- Small insects on leaves or stems
- Holes in leaves
Overwatering (attracts fungus gnats) Lack of airflow Contaminated soil or growing mediumSolutions:
Let the soil dry slightly between waterings to prevent gnats Use sticky traps to catch flying insects Introduce beneficial insects (e.g., ladybugs for aphids) Spray a mild neem oil solution (1 teaspoon per quart of water) to deter pests Tip: Avoid using chemical pesticides, as microgreens are eaten fresh.7. Microgreens Falling Over (Damping Off Disease)
Symptoms:
- Seedlings collapse at the base
- Brown or water-soaked stems
- Rapid die-off in patches
Fungal disease caused by excess moisture and poor airflow Overcrowded seeds creating a humid microclimate Unsterilized soil carrying fungal sporesSolutions:
Space seeds properly to improve airflow Use sterile soil or growing medium Reduce humidity and avoid overwatering Increase air circulation with a small fan Tip: Cinnamon is a natural antifungal—lightly sprinkle some on the soil to prevent damping off.