Nontoxic Weed Killer (Non-chemical, too)

Image: using steam to kill weeds

Battling Japanese Knotweed in Central New York is no trivial task; within days, even the smallest amount of root left after hand-pulling the weed sprouts new growth. While our Ollie’s Point project began in June 2019 with a Saturday of cutting and pulling all the knotweed we could from our revegetation site, we sought additional methods to battle regrowth effectively throughout the summer. Given our site is the shoreline of Onondaga Creek, we looked for alternative options to Roundup or other chemicals. This lead us to research about effectively using steam to control weeds.

Managing Weeds with Steam

Below are helpful articles and videos promoting the use of steam to selectively kill weeds without harsh chemicals.

Saturated steam an organic weed killer

CU Boulder employs steam to control weeds on campus, University of Colorado Boulder

Steam Weeding for Weed Control in an Organic Hopyard, University of Vermont

Non-chemical steam management of invasive Gorse weeds by Weedsteamers

Ultimately our group purchased the DynaSteam All-Natural Weed Killer from Northern Tool to test on our project site.

Weed Steaming Experience to Date

So far, so good it seems with steam. While steam does effectively avoid dragging harsh chemicals to our project site to then flow into the creek, it does require us getting power to an otherwise powerless natural area. To test the use of steam for our project we had to additionally secure a generator for use which has limited how much testing we’ve been able to actually do this season.

Other notes from our testing so far is that, while the DynaSteam is an approachable size (and price point), it looses its pressure quickly requiring much starting and stopping while the water re-heats to the correct temperature and pressure. Those notes aside, it does seem as though regrowth is not occurring in the sections where we’ve used the steam. We’re using a pronged attachment to get the steam underground to the roots, as steaming at the rhizome level seems to have more long term promise than surface application alone.

Next spring we’ll be doing more controlled experiments in a section we can cordon off from any and all hand-weeding and will test using steam at the first sign of spring growth, and then later in the summer to test more accurately how well the steam does at discouraging regrowth. We’ll post notes of those experiments in the spring.