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The Latest Dirt - May 2023

Help Desk Responds to Phase of the Moon Timing

Client’s question:

Thank you for your “ASK US!” service. We will need to begin weed whacking soon, before our house is completely overgrown. Is there an optimal time to cut weeds based on the phase of the moon (or any other factors)?

Susan Heckly’s response:

Thank you for contacting the UC Master Gardener Program Help Desk with a question about weeds. The best time to cut weeds is as early as possible. Ideally, weeds should be removed before they get a chance to set seeds. Once seeds are formed, even if they are not ripe yet, they will continue to ripen on the cut plant. If you don’t remove them from the landscape, they will reseed and give you a great weed crop next year—and in subsequent years. There’s an old saying— “one year of seeds gives you seven years of weeds” from seeds that lie dormant in the soil.  

The University of California hasn't published research on phases of the moon and how they affect weed removal (or their effect on any other plants), so I can’t opine on that aspect.  

This link will give you more information about managing weeds in the landscape, both for new plantings and for established landscapes: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7441.html 

I hope this information is helpful. Let us know if you have more questions. Good luck with your weeds!