We use aspirin for common aches and pains. Some folks like to crush an aspirin, dissolve it in water and use the water to extend the life of cut flowers.
But some experimentation is going on that calls for using aspirin on plants to prevent or lessen the damage caused by disease. Some of the info is academic; some is anecdotal. All of it is fascinating.
The Agricultural Research Service has been experimenting on the use of salicylic acid solutions to protect potatoes from a disease transmitted by a beetle. Salicylic acid is the key component of aspirin that reduces inflammation and pain response in humans. In plants, researchers credit salicylic acid with triggering systemic acquired resistance (SAR), a kind of general readiness state that primes plant defenses against pending microbial or insect attack. Some describe it as boosting a plant’s immune system.
This piggy-backs on work down in the first decade of this century by Rebecca Brown, professor of plant sciences at the University of Rhode Island. Talking about her research in Fine Gardening magazine in 2006, Brown described spraying tomato plants with an aspirin solution as a protection against disease. This was compared to a commercial product called Messenger that triggers a similar response to aspirin in plants.
Brown noted that all the plants grew equally well. She also mentioned the aspirin-treated plants had more, but smaller, fruit.
Other folks are more enthusiastic. Some Master Gardener blogs compare the use of an aspirin solution to that of willow water. Old-timers used to use willow water to help cuttings develop roots. You chop up a bucket of willow leaves and twigs and cover the plant material with water. Let it set for 24-48 hours. Then, use the water on cutting beds or to water newly set plants.
Supporters of aspirin water say they get the same results — healthy plants, better root systems and greater disease resistance. Some gardeners even advocate gently watering seeds with aspirin water before you cover them in the garden.
If you would like to give this a try this season, any aspirin product will work, say both scientists and gardeners. The solution is 250 to 500 milligrams (one or two regular aspirin tablets) of aspirin per gallon of water. Treatments are made once every three weeks throughout the growing season. Here’s a word of warning — more is not better. Whether you use the solution as a foliar spray or soil drench, too much aspirin can burn the plant up.
If you do try it or have tried it in the past, let me know how it works out.