Time to control your weeds
September 30, 2004
MARCE LUCKE
Victoria County Master Gardener
Now that seasons are about to change- and all your work has
produced bud and bloom throughout the summer and into these transitional weeks
- you will be able to relax. Well, not soo quickly. Everything is growing well
and if it looks good to you, think how good it looks
to the insects, birds and squirrels: "Lunch is served!"
Assuming that you followed most of the rules about bed
preparation and fertilization, your lawn and gardens should be in fine
condition. To keep them that way, you must do a regular patrol about the
grounds to watch for diseases, insects and weeds. No matter how much care you
have put into your gardening, weeds will find a way to come out and challenge
you! By the wind, birds, animals and even in the root
ball of new plants, weeds will come in and attempt to invade.
Some seeds previously dormant in your garden for several
decades can come up when just the right conditions develop. So what provoked
them to come up now? Those right conditions could have been the extra rain we
received this summer, light or heavy tilling of the soil that could bring up
seeds buried for decades, or weakening of turfgrass
allowing, sunlight to warm the soil and germinate the seeds. Once they sprout
and grow, not only do the weeds look bad, but they also compete with the
desirable plants for space, light and nutrition.
To control weeds you need to first identify them. If you
need help in doing this, it is a good time to check resources on weeds at the
Extension office or in books at the library- or even search the Web for sites
or links on weeds. If you have children in your family, this is a good time to
enlist their help. They will learn to recognize weeds and will see insects that
you might miss. Turn it into a game by giving them a bag or bucket to collect
their weeds and see who can get the largest, strangest, and the one with the
longest root system. It is especially important that they learn to pull the
whole weed - and not just break the stem. Chopsticks are good weeders and so are old table forks. If they are composted,
turn the compost pile frequently to prevent them from growing. Or, just simply
bag them for the trash.
So what are weeds anyway? Weeds are defined as plants
growing out of place. They come in all varieties - tall, short, spreading
ground cover, but mostly unsightly. They are invasive and destructive to your
garden plants because they take up space, light and nutrition, hindering the
growth of other plants. As we move into the fall season, winter weeds will
began sprouting from late September through October and possibly even through
November and December depending on the weather. Winter weeds that typically
cause problems in our yards are annual bluegrass, bur clover, chickweed,
dandelion, henbit, lawn burweed, stinging nettle and
thistle.
A thick, dense turfgrass usually
identifies an area that will seldom have weed problems. So, the best advice is
to follow management practices that maintain a thick turf. But a little bit
goes a long way - and just enough is better. Too much high management, i.e.,
fertilizer, water, etc. will encourage pests, thus weakening the grass and
resulting in more weeds.
If you stand above your lawn looking down at it and see
either dead spots or a weak turf at this time of the year, you will probably
have one or more of the weeds listed above within a month or two. Since it is
always recommended to first use the least toxic weed control method, try
pulling the weeds as your first technique. If that is not your cup of tea, then
apply a thin layer of mulch around the desired plants and also apply it in
walking paths. This will keep the soil from being compacted so less tilling is
needed, less weed seed is tilled up, and it will also help keep soil
temperature and moisture more uniform.
Another option to minimize winter weeds is to use a
pre-emergent herbicide. Applied now before the weeds sprout, the herbicide will
kill the sprouting seeds before they establish. There are several different
pre-emergent herbicides that range from organic to typical herbicides.
An organic approach that has been promoted recently as a
pre-emergent herbicide is corn gluten meal. Universities have proven that CGM
has pre-emergent activity. Furthermore, proof has shown that it takes at least
20 pounds per 1,000 square feet - and twice or three times that rate is better.
While CGM works, it typically only controls about 50 percent of the seed
sprouts. Also at the 20-pound rate, the natural nitrogen in CGM is twice the
recommended fertility rate needed, and this may cause problems. (More effective
pre-emergent weed control is demonstrated with a 66-, 132- or 198-pound rate of
CGM, but the nitrogen level gets even higher.)
Some of the inorganic chemical herbicides that may provide
not only higher percent weed control, but may even be more economical include
(with chemicals listed in parenthesis): Green Light Products - Amaze Grass and
Weed Preventer (benefin and
oryzalin), Green Light First Down Granules (benefin and trifluralin), Green
Light Portrait Broadleaf Weed Preventer (isoxaben), and Green Light Betasan
Crabgrass Preventer (bensulide),
Other products include Vigoro Preemergent
Crabgrass & Weed Control (dithopyr), Scotts
Company Halts Crabgrass Preventer (pendimethalin), PBI/Gordon, Inc. Betasan
(bensulide),and Fertilome Winterizer & Weed Preventer (simazine).
The key is to become better informed. First recall what
weeds were a problem last year. Second, if you think you
will have that problem again this winter, search for the product that has the
best control of them with the least cost and environmental concerns. Third,
read the label thoroughly and apply the product according to directions,
following all precautions.
If you miss this pre-emergent season to control your winter
weeds, you have one more chance once they have sprouted and begin growing.
Prior to the weeds reaching taller than 3-4 inches, identify which ones are
problems and follow with steps two and three listed above - only now searching
for a post-emergent product and applying it according to directions.
All of this is a lot of extra work - when it is far easier and more economical to strive to have a thick turf from the start without having to fight the weeds. But hopefully now weed control can be a whole lot easier, and by now you see why you can't seem to garden without weeds!