Be-A-Better-Gardener The World of Weeds

 

Be-A-Better-Gardener
The World of Weeds

Wood sorrel, Oxalis corniculatus, a common summertime garden weed in this area.

By Thomas Christopher

 

Weeds are the ultimate opportunists – they are experts at seizing on any resources left unclaimed by your garden plants, and they flourish in conditions such as heat and drought that challenge other vegetation.  Indeed, experiments conducted by scientists at the U.S. Department of Agriculture indicate that weeds will actually benefit from global warming:  when grown in the levels of extra heat and carbon dioxide predicted for the mid-century, weeds grew faster and more than twice as big, also producing more allergy-inducing pollen.  Even in current conditions, though, weeds are formidably prolific.  A single chickweed in your lawn can bear 15,000 seeds; that lamb’s quarter in your vegetable patch produces a crop of some 50,000 seeds.   In addition, these weed seeds are remarkably persistent, surviving decades or even centuries in the soil to sprout as soon as conditions become favorable.

There’s no easy remedy for such a vigorous enemy once it is established in your garden.  It’s far easier and more effective to practice prevention.

Weeds thrive in a disturbed habitat, so minimize disturbance to your soil.  In particular, avoid tilling as much as possible.  Exposure to light for even a fraction of a second is sufficient to cause many weed seeds to break dormancy and begin growing – by churning the soil and bringing many buried weed seeds to the surface, even if only temporarily, tilling usually prompts an explosion of weeds.  Refrain from stepping in garden beds so that you don’t compact the soil and you’ll find that you need to dig far less often. Top up beds with an inch of compost occasionally and you’ll promote a healthy population of earthworms who will do your digging for you – without awakening weed seeds.

Be precise in targeting your watering, so that you give your plants just the moisture they need and you don’t splash any excess on the surrounding area.  Excess water will enable and encourage weed growth.

Be precise, too, in your fertilization. Send a sample of your garden soil to the state agricultural laboratory for testing, so that you’ll know exactly what nutrients, and how much of them, you should apply.  Excess fertilizer is also an invitation to weeds.  Keep in mind when reading fertilizer labels that the manufacturers want you to use the maximum dose so that you’ll have to return to the garden center for more.  I prefer to fertilize at a lower rate than what is recommended on the product label, but also more often.  Instead of gorging the plants with a big blast of nutrients, the smaller and more frequent applications administer the nutrients at a rate at which the plants can better utilize them.

Plant closely.  Don’t crowd the plants – that encourages weak growth and disease – but place them at the minimum recommended spacing.  That leaves less space open for weeds to colonize.

Mulch around your plants to smother weed seeds.  I’m not a great fan of bark mulch; among other things, as it decays it temporarily extracts nitrogen, a major plant nutrient, from the soil.   Shredded leaves, which I collect by the bagfuls every fall after running them over with a mower, have a more natural look in my opinion, and they decompose into humus more quickly.  Mulch also reduces the need for summertime irrigation by keeping moisture from evaporating out of the soil.

Finally, if weeds do invade, try to make sure they don’t go to seed.  If you don’t have time to uproot them, use your string trimmer to cut them down.  Remember how prolific they are, and how long-lived are the seeds they produce.  As the old timers used to say: “one year’s seeding makes seven years weeding,” which is, in fact, a considerable understatement.

 

Thomas Christopher is the co-author of “Garden Revolution” (Timber Press, 2016) and is a volunteer at Berkshire Botanical Garden. berkshirebotanical.org

Be-a-Better-Gardener is a community service of Berkshire Botanical Garden, one of the nation’s oldest botanical gardens in Stockbridge, MA. Its mission to provide knowledge of gardening and the environment through 25 display gardens and a diverse range of classes informs and inspires thousands of students and visitors on horticultural topics every year.  Thomas Christopher is the co-author of Garden Revolution (Timber press, 2016) and is a volunteer at Berkshire Botanical Garden. berkshirebotanical.org.

 

 

Author: Harlem Valley News