Watering greenhouse and polytunnel — different rules than in the garden

Greenhouse and polytunnel — watering differently

Plants under cover are completely dependent on you. No rain will help them. And this changes everything.

Why greenhouse requires special attention:

• Temperature inside is higher → soil dries faster
• Enclosed space → air humidity can be too high → fungal diseases
• No natural rainfall → you're the only source of irrigation

  Greenhouse watering rules:

  1. Drip irrigation system is not an option — it's a necessity
  Watering from a watering can over the leaves in a closed greenhouse is a straight path to powdery mildew, alternaria, and blight. Water must reach only the roots.

  2. Ventilate after watering
  After each watering, open greenhouse windows or doors for at least 30 minutes. Excess moisture must have somewhere to escape.

  3. Water in the morning — even more important than in the garden
  Evening watering in a closed greenhouse + nighttime heat = perfect conditions for fungi. Never in the evening.

  4. Monitor soil temperature
  In summer greenhouse, soil in containers can overheat — roots suffer. Use light-colored containers or cover them.

  How much to water:
  In July-August, greenhouse may require daily watering. In spring and autumn every 2–3 days.

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