How to use soap in the garden
by Lorene Edwards Forkner
Soap is a remarkably versatile, almost-magic potion to keep on hand in the garden. Whether you're battling grime, pests, sticky blades or poison oak, soap's endless varieties can tackle a laundry list of garden chores indoors and out.
Identified on most labels as "potassium salts of fatty acid," simple soap is safe in one dose and deadly in another. Always follow package directions carefully.
Garden soap uses
Bug killer — Insecticidal soap kills most soft-bodied insects, such as pesky aphids, by dehydration. You have to spray the actual bug to kill it. Repeat applications may be necessary. Carefully note label warnings for plants susceptible to damage by the product.
Deer repellent — Highly fragrant bar soap hung in vulnerable shrubs and trees offends (and repels) a deer's delicate sense of smell. The trick of course is to make bar soap ornaments look better than deer damage.
Stop slugs and snails — First thing in the morning or after a rain, handpick slugs and snails. Drop the leaf-ravaging mollusks into a bucket of soapy water to send them quickly to a bubbly grave.
Weed killer — Super-strong soap solutions kill weeds on contact by drying up soft plant tissues. This solution is most effective on tender, annual weeds before they go to seed.
Clean up indoor plants — Remove light-blocking dusty build up and other indoor contaminants from houseplant foliage by spraying with a mild soap solution and wiping the leaves clean. This is especially important during winter when plants may struggle to get enough light.
Spreader/sticker — For improved performance of spray-on disease controls, add a soap-based product to help the formula adhere to the plant. Many fungicides and dormant spray solutions already contain a spreader/sticker, so read the label.
Wetter water — Apply a very mild soap and water solution, such as used dish water, to dried-out houseplants. Peat-based potting mix is difficult to re-wet once it dries out. Plants can wither from drought if water isn't getting to the roots. As a natural surfactant, soap helps break surface tension, helping water penetrate the most resistant soils.
Lubricate saws — Swipe a bar of soap over the blade of your hand saw and winter pruning chores will proceed with ease. Soap on metal helps it go through wood more easily, resulting in straight, accurate cuts and less work for the gardener.
Relief from poison oak and poison ivy — Choose soaps specifically designed to treat the nasty rash caused by urushiol oil, a sticky toxic substance found in the sap of these noxious plants.
Clean up — Keep fingernails clean while working in the garden by scraping them over a bar of soap before heading outside. Tiny slivers of soap prevent dirt from caking under your nails and wash out cleanly.
At the end of the day, nothing beats a long, hot soapy bath and a sound scrubbing to clean and soothe weary gardeners. Insecticidal soaps, disease controls and other soap-based garden formulas may be found at your local nursery, garden center or hardware store. Save the fancy stuff for yourself at bath time.
Lorene Edwards Forkner is a Northwest-based freelance writer, food enthusiast and garden designer. Visit plantedathome.com to read about her thoughts on life, work, home and garden.