Watering is a daily greenhouse job in warm weather — pots and grow-bags dry out fast under glass — but how you water matters as much as how much. Good technique keeps plants steadily hydrated while avoiding the wet, humid conditions that cause disease.
When and how much
Check plants daily in the growing season; in high summer they may need water morning and evening. Water thoroughly so it reaches the whole root ball, then let the surface dry a little before the next round — steady, not constantly soggy. A moisture meter“>moisture meter helps you avoid guesswork and overwatering“>overwatering.
Water at the base, in the morning
Water the soil, not the leaves, and do it early in the day. Wet foliage and evening watering leave surfaces damp overnight — ideal for botrytis“>botrytis and downy mildew“>downy mildew. Morning watering lets any splashes dry.
Automatic watering for hot days and holidays
Because greenhouses dry so fast, automatic watering is worthwhile: greenhouse irrigation“>drip systems, timers and capillary matting keep plants watered while you’re at work or away — see the drip kits & timers“>drip kits & timers guide.
Don’t forget humidity
Watering and humidity are linked — over-watering plus poor airflow raises humidity and disease risk. Pair good watering with ventilation“>ventilation; see greenhouse humidity“>greenhouse humidity.
Quick questions
How often should I water greenhouse plants? In warm weather, check daily and water when the top of the compost starts to dry — often daily, sometimes twice a day in heat. Ease off in cool, dull spells.
Related guides
- Overwatering vs underwatering“>Overwatering vs underwatering · greenhouse irrigation“>greenhouse irrigation · humidity“>humidity · greenhouse growing hub“>hub
