Thirsty Light Takes Worry out of Plant Watering

By Jim Bray
March 6, 2008

Do you have a habit of killing your house plants because you forget to water them?

If so, the Thirsty Light digital plant monitoring system may be the answer to your chlorophyll-challenged conundrum. It's a nifty little system that lets you know when your plants need a dash of H2O – and you don't even need to get your fingers dirty feeling the soil!

It isn't a product for me, though. I don't water the plants at home, indoors or outdoors; that's my wife's territory and better for her to kill them than for me to perform that service and face the inevitable blame. Instead, I've been given responsibility for cleaning the cat boxes, where the damage I can inflict is minimal and less permanent.

Suits me. But my wife loves the pastoral feeling she gets while puttering with the plants, and more power to her.

When I used to work in corporate towers I always felt sorry for the poor soul responsible – either voluntarily or not – for keeping the office plants happy. While some people undoubtedly take to the task happily, it strikes me as a penalty meted out to whomever draws the short straw – and unlike many productivity measurements in the corporate tower, if the plant waterer falls down in his or her duties the results are apparent more quickly than in the quarterly report.  

This is a heckuvan argument in favor of fake plants, my foliage of choice ever since it became apparent years ago that I have a black thumb and kill any flora I get near. Heck, the only plants I've ever had success with are face plants, and that's not something I want to brag about.  

If it were up to me, I'd happily remove every plant, fake or not, and replace them with LCD screens. Alas, it isn't only up to me.

So when the people behind the Thirsty Light sent me a sample of the $10 device I got my wife to try it for a while and then give me her impressions (you should see her do Hillary Clinton!). She deemed the Thirsty Light to be a cool little gadget that works so well even I could use it were my wife to let me near the house plants.

Which ain't about to happen.

The manufacturer says the Thirsty Light uses Drypoint Technology to monitor your ferns' fluidity factor and take away all the worry that stems from having to keep your plants perpendicular. The system includes a sensor at the tip of the probe (the part you shove into the ground like a tiny lightning rod) and a digital circuit housed in the pod itself, which looks kind of like a green bulb. They say the Thirsty Light measures the electrical resistance of the soil environment (the resistance supposedly being lower when moisture is present and more dissolved salts are in the moisture).

The circuit measures this resistance once per second and, if the plant needs a quick quaffing, the Thirsty Light emits a pattern of blinks. If everything's tickety-boo with your favored greens, the Thirsty Light goes back to sleep for another second.  

Not only that, but as the soil gets drier the blinking pattern speeds up, as if the plant's starting to panic because, so far, you've ignored the warning being flashed at you plaintively.

The gadget's powered by two replaceable one-and-a-half volt lithium ion batteries the company says should last up to a year – and there's even a special blink pattern to let you know when the batteries need watering – er, replacing.

By using the Thirsty Light to monitor your flower children, you could also be kept from over watering the damn things: you can ignore them safely until the Thirsty Light fires up and starts "visually hollering" at you.

Thirsty Lights are sold individually or in packs of three, six and 12 – so you could use a separate Thirsty Light to monitor each plant  if you want to – I'm sure the manufacturer would love you for that. Or you can haul one Thirsty Light around from plant to plant, even turning it off to save battery life when you aren't using it, though that seems like it's kind of defeating the purpose.  But what do I know about it?

My wife moves our sample around periodically, but for the most part she leaves it in one pot and when the Thirsty Light fires up she takes that as a cue to check the rest of the plants, too. It seems to work well; our home is still infested with green, leafy things.

The Thirstylight.com website also offers a section with hints on how to exploit the product to its best, including how and where to stick it – which I daresay has nothing to do with their warranty policy. What they actually mean is that you can tailor the system to a particular plant's preferences by inserting it into the soil at different depths for different plants.

The site also offers a watering guide, plant "cultural preferences" (ours seem to like rock and roll and Star Wars movies), a "watering alert" grid that outlines the Thirsty Light's blinking patterns. They even have a page, to the surprise of few, I'm sure, where the sell accessories designed to make your plants' life more pleasant. If you care.

Sounds like the perfect tool for people who want to turn over a new leaf.

Copyright 2008 Jim Bray