When is the best time to water indoor plants?

Watering at the wrong time increases the risk of pests, fungal growth, leaf, stem and root rot. No thank you! Morning? Middle of the day? Early evening? What’s best? Let's find out...

I didn’t think when you watered mattered that much until I lost my first plant to over-watering. My plant heart is tougher now but at the time it really upset me. Nothing like a plant loss early in the hobby to make you go into research mode. Fake news alert. I found SO many myths. A lot of what I thought was watering gospel turned out to be the opposite of what the research proved. 

The evening

Have you been told to avoid watering during the hottest part of the day and to water in the early evening instead? Me too! Don’t do that. Evenings are best avoided because of evaporation and transpiration (I think of transpiration like a plant breathing). Around 99% of water a plant takes up does NOT stay in the plant. Tiny pore-like holes on leaves, called stomata, take in carbon dioxide and ‘breathe out’ oxygen and water.


Evaporation and transpiration reduce overnight, so watering in the evening means water sits around for longer. That increases the risk of fungal growth, rot and moisture-loving pests like fungus gnats. If you've got fungus gnats this is how to get rid of them once and for all (they would win the award for the most annoying plant pest, but luckily one of the least harmful to our plants).

The middle of the day

Another one I was told was not to water in the middle of a hot, sunny day because it burns leaves. Another myth! If your plants are showing signs of draught, water them when they need it, don’t wait! Watering is NOT a cause of leaf scorch. Wet leaves combined with high heat or bright light (even direct sun) are totally okay (oil on leaves + direct sun is not okay though, that one is true).


But one thing you can do to avoid the burn is watch the salt. Salt IS one cause of leaf scorch. Using a low-salt fertiliser helps reduce the risk. Look for one free of urea, chlorides & sodium (one that ticks the boxes is GT). But don’t skip the fertiliser all together! A lack of potassium (that's the K in NPK), increases water loss, causing brown tips, leaf margins, and leaf scorch. Ouch.

(drum roll please) When is the best time of day to water indoor plants?

Mornings! Perfect timing. That gives plants more time for water to dry during the day which reduces the risk of rot, fungal growth and bad bugs. Sounds good to me :)

Keep learning

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