The Magic of Rain Water
By Paul James
Did you notice how quickly your lawn and garden greened up after last weekend’s showers and thunderstorms? Here at my place, the transformation was startling. But why is that? Why is rain water so much more effective at perking up plants than tap water? There are several reasons, actually. And there’s one that’s rather shocking, because it involves lightning.
Obviously, rain brings moisture, but with it comes cooler air temperatures and overcast skies, all of which relieve the stress of heat and drought on plants. And rain falls fairly uniformly throughout landscapes, soaking areas that even the best sprinkler systems — not to mention hand watering — often miss.
Rain water also washes plant leaves, removing accumulated dust and grime, giving plants a lusher, cleaner, and greener appearance, and more importantly unclogging their stomata, tiny pores that regulate the exchange of carbon dioxide and water in and out of leaves.
Rain water chemistry is also different. It contains a lot more oxygen than tap water, so the threat of root rot caused by anaerobic soil conditions is lessened. And it contains a good deal of carbon dioxide, which combines with minerals in the atmosphere to make the rain slightly acidic. The acidity facilitates the release of micronutrients in soil such as copper, manganese, iron, and zinc, all of which are essential for plant growth.
But to a former chemist and science geek like me, it’s the effect of lightning on atmospheric nitrogen (which makes up 78% of the atmosphere) that I find especially cool. During a thunderstorm, lightning actually has the energy to cleave the strong bonds of nitrogen in the air. The free nitrogen then combines with oxygen in the air to create nitrogen oxides, which dissolve in moisture to form nitrates, which fall to the surface of the soil, which are absorbed by plant roots. And few things turn plants greener than nitrates.
Pretty cool, huh!?
Two weeks ago I described my Bermuda grass lawn as being “crunchy” underfoot. And it looked as bad as it sounded, despite watering it generously once a week. But after the rains last weekend — and the nitrates! — it greened up beautifully. Unfortunately though, the heat is on again, and I’m pretty sure my lawn will suffer just as it did in July.
In other words, it’s gonna be crunch time all over again.
Happy gardening, ya’ll.
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