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Weeds - Never let ’em set seed


Published: 03/29/2012


Have you ever wished you could grow vegetables without hours of weeding? If you are like most gardeners, I bet you
have. The good news is that with a bit of dedicated effort, you can reduce the weeding you do year by year until your vegetable garden is virtually weed-free.


The key is to know a bit about something called the ‘weed seed bank’. Most people don’t realize that a weed can produce
literally thousands – or even millions – of seeds per plant. Seeds ‘in the bank’ can remain viable for quite a long time and sprout when conditions are right. That means it will take several years for you to reach your weed-free goal.


How many years? The answer depends on the weed species. Seeds of most annual weedy grasses die after two or three years, but some broadleaf weed seeds can last for decades.

On average, though, the bulk of your weed seed bank will be depleted in about five years if no additional seeds are
added. Never let one weed go to seed, or else you will be back to square one!


What about seeds blown onto your garden or dropped there by birds? They shouldn’t be a big problem. The seeds for most weed species drop directly to the ground, close to the mother plant. There are only a few bad actors with windborne seed, such as dandelion, sowthistle and groundsel. And it is rare for annual weed seeds to be spread by birds.


To hasten the path to a weed-free garden, I recommend a two-pronged strategy: drive down the number of viable seeds in the
soil and quickly intervene when those that remain sprout. I use solarization, mulching, hoeing and hand pulling. (Solarization involves covering the soil with a clear plastic tarp for several weeks in the summer to heat the soil and kill weed seeds. It may sound far-fetched, but it works.)


While there is never a 100% guarantee in the natural world, if you follow a ‘never let ’em set seed’ strategy, I can virtually guarantee that you will soon be doing a lot less weeding in future years.


This column is provided by the Weed Science Society of America. Robert Norris, Ph.D., is an avid gardener and a Fellow of
the WSSA.

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