The Gesneriad list once again gives us something interesting to think about. The topic relates to passive hydroponic growing of your violets and gesneriads by placing them in a truly soil-less mix thats only purpose is to hold the plant's roots in place. This could be an item such as perlite or clay pellets which act to support the plant while it gets all it's nutrients from the enriched water that gets passed over its' root system. The fact that the kitty litter is Diatomaceous Earth is important because DE powder is used to KILL pests and insects mechanically by making cuts and abrasions on the pest as it comes into contact with the "sharp" qualities of the DE. Diatomaceous Earth is mined from "glass-like" sea creatures, diatoms, made of mostly silicon dioxide. Passive hydroponic growing is a very interesting topic and one respondent, BF, commented about it:
I'm using a product I read about on the Bonsai4Me website: http://www.bonsai4me.com/Basics/Basicscatlitter.htm I got my big bag of DE gravel at my local NAPA auto parts place, "part" number 8822 for $7.99 plus tax. The grains are up to 1/4" (.5 cm). It looks just like the photo on the website. So far, so good. The only plant I've lost has been an adoptee Wisdom violet that was sick from soil mealies when I rescued it. Its soul mate has put out a new leaf since I treated and potted them into DE. The only red bag of Wal-Mart cat litter I found was the old style clay that melts right away rather than "Special Kitty® Natural" that the article says is actually DE. The Wal-Mart clay litter has the words "Absorbs odors naturally" in small print, so shoppers really need to check the ingredients info.
I'm using a product I read about on the Bonsai4Me website: http://www.bonsai4me.com/Basics/Basicscatlitter.htm I got my big bag of DE gravel at my local NAPA auto parts place, "part" number 8822 for $7.99 plus tax. The grains are up to 1/4" (.5 cm). It looks just like the photo on the website. So far, so good. The only plant I've lost has been an adoptee Wisdom violet that was sick from soil mealies when I rescued it. Its soul mate has put out a new leaf since I treated and potted them into DE. The only red bag of Wal-Mart cat litter I found was the old style clay that melts right away rather than "Special Kitty® Natural" that the article says is actually DE. The Wal-Mart clay litter has the words "Absorbs odors naturally" in small print, so shoppers really need to check the ingredients info.
As you know, it's questionable as to whether DE works to kill critters when it's wet, but I'm hoping to find a side benefit is that thrips larvae, gnats, and any soil mealies are eliminated. And I hope it reduces the frequent repotting peat moss mixes require. As a plant grows and becomes root bound, the roots grasp and hold the gravel in place. The plant can be simply repotted into a larger pot with additional DE or clay granules. There's no waste and no brushing the old soil away from the roots. An additional quality is that the granules are washable and re-useable.
The African Violet Magazine carried an interesting article in the March-April 2006 issue, "Wicks and Rocks" by Irving Tashlick who uses clay pellets, reservoirs, and the wicking system. He comments, "I think the reasons the [passive hydroponics] methods....are successful in growing African violets and other gesneriads are that there is a great similarity to the conditions achieved with 'Texas Style' cultures. There are many air spaces to allow free gas exchange at root tips, the roots have free access to moisture and nutrients and the system depends on capillary action."
