Watering Plant Foliage

When I water, I like to spray the plant leaves in order to clean them off and cool them down. Is this OK? -Matt

A spray of water is a great way to remove buildup and grime from foliage and to dislodge aphids and other insects. However, wet foliage and soggy soil quickly invite fungal diseases, so it’s best to spray your plants only occasionally, and in the morning, so that the leaves have a chance to dry completely during the day.

Gardening Myth

We’ve all heard the warnings that water droplets concentrate the sun’s rays and burn plant leaves. This is actually a myth, although if your water is high in dissolved salts and minerals, frequent spraying can result in a damaging buildup on the leaves.

As for cooling your plants, it’s true that wetting the foliage can reduce leaf temperature, which reduces evaporation and can help your plant conserve water. While it’s not recommended as a daily habit, some gardeners head out on extremely hot, dry days to cool down particularly heat-sensitive or fragile plants.

However, routinely spraying your plants during the heat of the day will waste a lot of water that might be more useful around the root zone. Before you rely on overhead spraying to cool your plants, make sure you’ve taken these steps to protect your garden from the heat:

  • Water your plants regularly and deeply at the roots. Well hydrated leaves are your best defense against temperature extremes.
  • Mulch your plants generously, to cool the roots and hold in moisture.
  • Choose plants that are appropriate for your planting zone, and consider landscaping with drought-tolerant plants to reduce watering needs.
  • Use overhead spraying only as an emergency measure in extreme heat waves. High temperatures and low humidity cause plants to lose water very rapidly.

Further Information



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