"The only two herbicides we recommend are cultivation and mulching."

—Organic Gardening Magazine

A better mousetrap? Pharm Solutions, Inc. thinks so.

The Washington Corporation has recently received Environmental Protection Agency (EPA) registration for “the world's first food-grade organic herbicide.” Weed Pharm is a non-selective weed and grass killer with food-grade vinegar as the active ingredient. Pharm Solutions manufactures a wide variety of chemical garden products which includes the only U.S. Department of Agriculture (USDA) Certified organic pesticide. Many extension offices are only permitted to recommend the use of products that have been registered by the EPA so it is important to have an approved organic product for Extension Agents and Master Gardeners to suggest when requested. Weed Pharm is certified organic by Oregon Tilth and will be commonly available this year in lawn and garden supply stores.

Studies have shown that for vinegar to be most effective as a weed killer the percent of acetic acid must be stronger than the 5 percent acetic acid/vinegar we have in our kitchens. Herbicidal vinegar with a 20 percent acetic acid composition is fast acting and most effective on young, actively growing annual weeds. Vinegar does not move into the roots of treated plants, so only top growth is killed. This means that it will not be effective on perennial weeds. Non-selective means that you must take care during application as the solution will kill any and all plant tissue it touches.

A weed control research study done on wine grapes in San Joaquin County found Weed Pharm to be the most effective (of three commercial brands) herbicide used on a test vineyard over the short term, three days after application. However, after 28 days it was the least effective. This result will be acceptable for certain applications though not for others. Since the product is so new, there is very little practical information available and it remains to be seen how adaptable it will be to farm and garden. I imagine that it could be quite valuable to small farms and gardens which have an organic designation and are able to apply the herbicide frequently enough.

Weed Pharm is claimed by the manufacturer to be an alternative to chemical herbicides. All material things, however, can be broken down into chemical compounds. Vinegar is a chemical compound; therefore, Weed Pharm IS a chemical herbicide that also happens to be organic.

There are dangers associated with the use of Weed Pharm, as with the use of any synthetic or organic chemicals so the warning label must be carefully read and followed. Desirable plants need to be protected from potential spray drift.

A postscript to my recent attempts to resurrect year old paperwhite narcissus bulbs: The experiment failed. I had always heard that bulbs were exhausted after being forced and I will have to agree that is the case. Some of the bulbs did grow long lanky leaves but none set buds or bloomed. From now on I’ll treat the bulbs as annuals.

In the February Garden:

Work in the garage this month to make and/or repair birdhouses and feeders, and mason bee blocks for nesting native bees.