This little northwest mist we just experienced reminds me that this is the time of year when all those little weed seeds that have been lying dormant in our soils suddenly get a notice from Mother Nature that it is time to wake up and start growing. There are 3 environmental signals that cause this response…
First and foremost, our days are getting shorter (and have been since we passed the Summer Solstice way back in June). This is a trigger for fall germinating seeds. Along with the shorter days, our nights are getting cooler, which is yet another signal to wake up. And finally, a little moisture just sets all of this commotion into gear and before any of us realize what is going on, our gardens suddenly take on a green patina of freshly sprouted seedlings of chick weed, shot weed, annual blue grass, and henbit, just to name a few. What is a gardener to do?
Fall weed control is best handled by prevention rather than trying to clean up the mess, especially if it is left until spring when weeds will seemingly grow several inches a day. We have tools called “pre-emergent herbicides”, which when applied before the seeds actually germinate, will stop these weeds in their tracks and have no deleterious effect on plants that are already rooted and growing. Commercial products like Casaron and Preen are two examples of pre-emergent weed preventers that when used according to label recommendations, are effective tools against fall weed invasions. Surprisingly, corn gluten can also act as a natural weed preventer (and ultimately breaks down into a source of nitrogen fertilizer).
Unfortunately, these products decrease in their efficacy the longer we wait to apply them and I am sad to say that our window of opportunity is rapidly closing. That being said, even if you already see weeds emerging, all is not lost. Skin off the surface of the soil with a stirrup type hoe (my favorite is the Hula Hoe brand) and then apply your product of preference.
If you are opposed to using herbicides, then the next strategy (and probably the best in my book) is to cover any bare soil with an inch or more of compost. Compost, used as a mulch in this case, will smother any weed seeds in addition to acting like a sponge to absorb moisture, minimize compaction, insulate the ground, and add nutrients and microorganisms to the soil all winter long. Everybody wins when we mulch our beds in the fall.
This fall phenomenon of seeds germinating is not all bad news. It also just happens to be the absolute best time to plant or reseed a lawn. Now until the end of September is when we will have to best success establishing a plush and healthy turf area, and considering the brutally hot summer we just experienced, I would imagine an awful lot of gardeners have their work cut out for them.
In addition to grass seed, there are multiple types of veggies that can be sown now and actually harvested within the next 60 days. Arugula, lettuce, spinach, beets, carrots, radishes, broccoli, kale, and chard are just a few of the options. Of course, you can also just pick up some transplants from the garden center if you want to get a jump on the season.
Fall seed germination can be a mixed bag, but if we are smart, we can make the most of it. Stay safe and keep on gardening!
