http://www.telegraph.co.uk/science/science-news/7823032/Sunburnt-plants-myth-is-debunked.html Interesting info. for this time of year. Margaret
Locally generated remarks dating from 2002: The Bottom Line • Wet foliage is not susceptible to sunburn • Analyze site conditions to ensure optimal root and shoot health and prevent drought problems • Any time plants exhibit drought stress symptoms is the time to water them • Optimal watering time is in the early morning; watering during the day increases evaporative losses, and evening watering regimes can encourage establishment of some fungal pathogens • Do not overuse fertilizers and pesticides, especially those containing sodium or chloride salts • If using recycled or gray water, consider running the water through a filtering system before applying it to plants http://www.puyallup.wsu.edu/~linda chalker-scott/Horticultural Myths_files/Myths/Leaf scorch.pdf
While visiting the rainforest area of Panama, with rainshower after rainshower followed by rays of sun directly shining through gaps in the tree cover, and the accompanying heat, one never sees symptoms of burning on foliage...
I remember a big discussion about this on Gardenweb a while ago. The upshot was that its not the sun thats burning the leaves but rather the salts in the water getting left behind as the water evaporates burning the leaf surface.
That makes complete sense. The water on leaves causing burn always seemed like a myth to me - but I have worried about it and avoided doing it. Some water (like mine) is really "hard" and has all sorts of things besides water in it.
After all it often rains while te sun is shining! Nature would surely protect against that inevitability!
