Forget What Grandma Says – It's Okay To Water Your Plants In The Mid-Day Sun

Pardon this interruption of our regularly scheduled coverage of ObamaCare debacles and setbacks, Obama scandals and manufactured crises, loss of US sovereignty, and exploding world crises, but  Horticulturist Linda Chalker-Scott, Ph.D of Washington State University has some crucial information for summer gardeners.

As we enter the hottest months of the year, another bit of well-meaning advice rears its annual head.
Magazine articles, books and web sites all warn against
watering plants during the heat of the day.

Just so you know, I have always been a skeptic of this particular bit of conventional wisdom. If one of my flowers looks stressed in the middle of the day, I’m watering it – scientific consensus be damned.

It’s good to know that science has caught up with common sense.

The Reality:
This is one of those myths that refuses to die. Although most (but not all!) of the .edu web sites I checked
dispel this myth, hundreds of other domains on the web
keep the misinformation alive. If your plants are
showing signs of water stress in the middle of the
day, by all means you should water them!

Postponing
irrigation until the evening (not a good time to water anyway, as this can encourage fungal pathogens) or
the following morning could damage your plants and open them up to opportunistic diseases.

There are many causes of leaf scorch, but irrigation
with fresh water is certainly not one of them.
Hundreds of scientific publications on crop plants, turf, woody shrubs and trees have examined foliar
scorch, and not one of them has implicated midday
irrigation as a causal agent.

What does cause damage,
however, is suboptimal plant-water relations, which can result in tip and marginal leaf scorch, shoot
dieback, stunted growth, and leaf abscission. After drought, the most common source of these problems
is salt, in particular salts containing sodium (Na) and/or chlorine (Cl).

If your petunias look like they’re dying of thirst – you might want to get out there right now and water them.