From my St. Pete Times column in 2006:

         We’ve all had to deal with fungus problems on roses, squash and more. And we’ve all had aphids, mealy bugs, scale and red spider mites feast on garden treasures too. Those funky smelling chemical fungicides and insecticides rarely seem to work for long,  and if they do, eating the produce or sniffing the blooms can be pretty scary! Hey, who wants to eat or inhale toxic chemicals? But for over 100 years Southern gardeners have relied on a cheap, non-toxic and VERY effective natural alternative they bought in grocery stores, and that thankfully we can now also order toll free or on-line.

   What is it? An old-fashioned  lye soap called ‘Kirk’s Castile’. Yup, dissolved in hot water this true soap (most “soaps” these days are detergents)  is an organic gardener’s dream come true as a non-toxic all purpose garden spray. I was taught this concept in the 70's when I was an idealistic hippie/art major living in Seminole Heights with wise elderly neighbors who’d used it since the 1930's. These women said  that back  when they were young gardeners  it wasn’t called “organic gardening”…. it was just a very cheap, tried-and-true common sense gardening aid…just splash  the used  dish and laundry water on plants with fungus and bug problems!

  To make a small batch of  soap spray, rub a bar of “Kirk’s Castile” against a cheese grater, then dissolve 1-3 heaping tablespoon of the soap flakes in 1 gallon of very hot tap water in an old plastic milk jug.  Let it sit a couple days, shaking the jug daily to dissolve lumps. Then pour the spray into a trigger spray bottle or your garden pump sprayer then spray the affected plants every 7-10 days till they are dripping. Be sure to apply the spray when you don’t plan on watering for a few days so it can cling to the leaves and do its job. Don’t be afraid to experiment with slightly weaker or stronger strengths as it is non-burning unlike some of the dishwashing detergent liquids you may have tried in vain.

  To make a big batch of concentrate for future use, drop a whole bar into a wide mouth gallon container. Fill that jug with 1 gallon very hot tap water and let sit a week, stirring daily. You’ll end up with 1 gallon of a thick soap concentrate that keeps just about forever in a lidded container.  To make a batch of spray, dissolve 1 cup of this concentrate in 1 gallon warm water, shake, then pour it into your sprayer. Thus a cheap bar of soap will make you SIXTEEN GALLONS of a very  safe and effective fungicide and insecticide that won’t harm the environment nor make your vegetables and flowers and herbs toxic. For tougher problems try 1 part soap concentrate to 10 parts water for a thicker, more potent soap spray. And there is little worry of leaf burn from harsh summer sun.

  How does it work? The  soap  alkalinizes the  leaf surface, but powdery mildew and black spot and sooty mold ( on citrus and gardenias) fungi need an ACIDIC leaf cuticle to grow on…plus as a soap it helps to rinse them off. Spray UP at the undersides of the leaves if you are after blackspot fungus on roses. 

  What’s cool too is that the coconut oil in the soapy water (true soap is an oil or fat plus lye) help suffocate bad bugs by plugging up their breathing holes and permeating their chitinous exoskeletons. (that’ll teach’em!) Aphids on new growth? Spider mites on leaf undersides? Mealy bugs or scale on the stems on shrubs? White fly on your tomatoes? Just spray the plant thoroughly till it drips. Quite often the wing coverings of our garden allies the ladybugs and lacewings seem to spare them by acting as umbrellas. Adding 1 cup of cheap vegetable oil to that soapy gallon and shaking it thoroughly will let you wipe out vast numbers of scale insects.

   Okay, its 2006, not 1976,  and I am a little more grounded and happily middle-aged now, but now more and more folks wish for less toxic ways to grow their garden favorites. So a century old  secret deserves to be better known and tried before we resort to  expensive chemical sprays that can kill many unintended and valuable inhabitants of our yards’ ecosystems and endanger our children and pets while adding to the burden of poisons endured by our own bodies, the groundwater and what remains of this beautiful state.

SOURCES:

Publix, Albertson’s Kirk’s Natural 1-800-825-4757 www.kirksnatural.com