Hort Shorts
Corn Gluten Meal
Corn gluten meal (CGM) is a natural substitute for synthetic preemergence
herbicides. Preemergence herbicides attack seeds while they’re
still in the ground, before the seedlings emerge from the soil. CGM
is a byproduct of commercial corn milling that contains the protein
fraction
of the corn. Its use poses no health risk to people or animals. In
fact, because it is 60% protein, corn gluten meal is used as feed
for cattle,
poultry, fish and dogs. In addition to the 60% protein, corn gluten
meal is 10% nitrogen, by weight.
The use of corn gluten meal as an herbicide was discovered during
turfgrass disease research conducted at Iowa State University. CGM
was observed
to prevent grass seeds from sprouting. Further research has shown that
it also effectively prevents other seeds from sprouting, including
seeds from many weeds such as crabgrass, chickweed and even dandelions.
Corn gluten meal is effective only against seeds, not existing plants.
Products made of corn gluten meal will not kill annual weeds that are
already up and growing. They’ll die on their own, though, by the
end of autumn. But most of the seeds they produce later in the season
shouldn’t sprout – provided you’ve applied the CGM
properly and at the correct time. Crabgrass, foxtail, purslane and
prostrate pigweed are examples of annual weeds found in lawns.
Existing perennial weeds such as quackgrass, plantain and dandelions
won’t be damaged by CGM, either. And, they’ll still come
back from one year to the next because their roots survive most winters.
What corn gluten meal will do is stop the seeds they shed each summer,
so the population of these particular weeds won’t increase. In
fact, because some will die of “natural” causes, their
numbers should actually decrease after several years of consistent
CGM use.
How To Apply Corn Gluten Meal to Lawns
Corn gluten meal is available in powdered and pelletized forms, both
of which work equally well. The pelletized form is easier to use, though.
Apply corn gluten meal first in late April/early May, then a second
time around mid-August. Spread the product evenly, at a rate of twenty
pounds
per 1,000 square feet of lawn. Water it lightly into the soil in order
to activate it. The CGM should remain effective for five to six weeks
each time you apply it.
Most annual and perennial weed seeds sprout in spring or early summer,
but there are a number of “winter annuals” that may sprout
either in spring or fall. Chickweed, shepherd’s purse and speedwell
(Veronica) are examples of winter annuals that may be found growing
in lawns. When these seeds sprout in fall, their roots live over winter,
giving them a head start the following spring. By the end of that growing
season, they die, just like other annuals. Because of these winter
annuals,
you should apply corn gluten meal to the lawn in late summer as well
as spring.
Results of Using CGM on Lawns
Don’t expect to see instant results from using corn gluten
meal. Every consecutive year you apply CGM – assuming proper
timing and rate – should give you better results than the year
before. By the fourth year, weed control should be very good.
When you use corn gluten meal you are also fertilizing the lawn,
which encourages it to grow thicker and help exclude weeds. Applying
CGM
at the recommended rate of twenty pounds per 1,000 square feet, twice
a
year, gives your lawn a total of four pounds of nitrogen annually – more
than enough to meet its needs. Corn gluten meal does not supply phosphorus
or potassium, however. You should have your soil tested periodically
to see if either nutrient should be added and in what amount. Contact
our office for more information at 773-233-0476.
Garden Applications
Corn gluten meal may be used safely in gardens around established
perennial plants, to keep weed seeds from sprouting. It can also be
used after
transplants have been in the soil long enough to have “taken hold.” Follow
label recommendations for application rates.
Wait until seedlings are up and growing well before applying corn
gluten meal to flower or vegetable gardens where seeds were sown directly
into the soil. CGM will stop most seeds from germinating.
The Downside
Potential problems with corn gluten meal stem from the fact that
extensive moisture and microbial soil activity and reduce its effectiveness.
You can control how much you water right after applying CGM, but you
can’t
control rainfall. Sometimes seeds that had been prevented from forming
roots can “outgrow” the problem.
Another potential drawback is price and availability. While it is
becoming more readily available, corn gluten meal is still significantly
more
costly compared to other Preemergence herbicides. Check places that
sell garden supplies, farm stores or county co-ops that sell seed and
grain
for hobby farms and some stores that specialize in selling food for
wild birds.
Avoid Glossy Plant Ads
They’re starting already! Purveyors of questionable plant deals
are busy trying to take advantage of people’s thirst for spring
planting. Glossy ads compete for our attention with coupons for fifty
cents off breakfast cereal or laundry detergent. But most of these
plant ads are not a bargain.
Take dwarf banana trees. They’re interesting as houseplants, but
I’ve yet to see them produce fruit year-round in a sunny window,
as promised in the ads, maybe in a large greenhouse or conservatory,
but not in an average home. Nor can you produce strawberries indoors, “even
in winter.”
Ditto, tree tomatoes, which, according to the ads, are “not to
be confused with an ordinary vine or a tomato plant.” “…simply
stand back and watch your tree quickly zoom to the full height desired
and supply you with yummy fresh garden tomatoes.” Don’t you
believe it! If the plants ever do produce fruit for you – and that’s
unlikely – it will be instantly apparent that they aren’t
tomatoes at all.
There are many legitimate mail-order (and Internet) nurseries whose
reputations are built on years of service. Put your trust in them – and in
local nurseries and garden centers. They know what can be expected to
grow well here…and what can’t. The nursery or garden center
down the road from you wants to keep your business. They’re not
about to make up wild claims for plants that are marginally hardy here,
at best.
Choosing Houseplant Fertilizer
Now that days are growing noticeably longer, it‘s time to fertilize
your houseplants since they’re finally coming out of the winter
doldrums and starting to resume more active growth. But there’s
always some confusion about which type of fertilizer to choose. There
are so many on the market.
Plants actually make their own food by converting light energy to
carbohydrates through the process of photosynthesis. Fertilizer simply
supplements
this process by providing nitrogen, phosphorus and potassium (and sometimes
minor or trace elements) needed for healthy growth.
Organic houseplant fertilizers act slowly, because they usually must
break down in the soil before becoming available to plants’ roots.
This means you run little or no risk of injuring your plants when using
them,
but you won’t see results for a while. The cooler you keep your
home, the cooler that moist soil will be and the longer it will take
for organic fertilizer to become available.
By way of contrast, inorganic fertilizers are in a form that plants
may use from the minute you apply them to the soil. But you must
take care
to apply them only to soil that is already slightly moist, to minimize
any chance of burning. Another way to help avoid burning is to mix
houseplant fertilizer half-strength. Labels tend to recommend more
fertilizer than
is really needed anyway especially for the less than ideal growing
conditions encountered by most houseplants indoors.
Spring 2003
Hort
Shorts | Hort Tips | Crabgrass:
A Weed’s
Weed! | Health & Household Tips | Perennial
Plant of the Year 2003 | Mulch Reminder | Using
Organic Fungicides | Bug Bites: A Bug Bite
is Not Always a Bug Bite | Lawn Care Calendar | Cybergarden
Sites | Pondering Early Planting? Think
Lettuce | Eggology | Soup
for Supper | Protein-Rich Diets and Weight
Loss
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