March is on our doorstep and people are getting excited about crabgrass.  Every time you turn on the television, you see commercials espousing the virtues of various products which should work magic on your lawn.  Visions of a beautiful lawn dance in our heads as we swing in our hammocks sipping iced tea.  Who says big people don't believe in Santa.

    Crabgrass is an annual grassy weed which germinates from seed in the spring through summer, and is killed by heavy frost in the fall, leaving dead and brown crabgrass plants all over the lawn.  Bermudagrass or "wiregrass" is a perennial grass which goes dormant with heavy frost leaving plants of a dead and brown appearance throughout the lawn, but the plant is alive at the root and making plans for the following growing season.  Both of these plants are sun lovers and will not be found in the shade.  I would guess that over half of the crabgrass preventers applied in the spring are being used on bermudagrass which has been incorrectly identified as crabgrass.   Indeed, you may have both plants thriving in your lawn, but you need to correctly identify your weed in order to develop a n effective weed control plan.  If your weedy grass has a long, green root then you are probably dealing with the perennial bermudagrass.  Crabgrass preventer will yield no results on this plant.

    Crabgrass will begin to germinate when the soil temperature reaches a consistent level of the mid 50's or greater.  Temperature and moisture are needed to sprout the seeds, so they may wait for rain in a dry spring.  People say "put your crabgrass preventer down when the forsythia blooms (45 degrees soil temperature)".  You won't be late following this rule, but your crabgrass control will wear off before all of the seeds have germinated.  In July or August, crabgrass will take over your lawn.  Crabgrass seeds begin to germinate in the spring and continue to germinate throughout the growing season.  Contrary to popular belief, the seeds do not all simultaneously jump out of the ground at 10 AM on March 29th.

    Let me give you a simple explanation of how crabgrass controls work.  These products are called "pre emergent weed controls" meaning that they are only effective if applied prior to the emergence (or germination) of the target seed.  Crabgrass preventers form a vaporous barrier over the surface of the soil which cannot be penetrated by the sprouting seed (which would also include grass seed).  Following application, a 1/4 to 1/2" of water or rain should follow to activate the product.  Depending on the product and its rate of application, the life of the barrier can range from 4 weeks to 24 weeks.  An overdose could give you control for several months, interfering in the fall seeding process of desirable grasses.  The barrier is broken down over time by higher temperatures, moisture, and microbial activity or "critters".  Variations of these conditions can effect the life span of your crabgrass control.  A good example is frequent use of irrigation which provides a high level of moisture, thus shorting the life of the crabgrass control.

    So...put your crabgrass preventer down in mid March, assuming you are not planning to overseed.  If you have a historical crabgrass problem, consider a second application in mid May.  This step will give you excellent control rather than failure.  There are many products available and I will list a few.

Dimension - Fairly new and very long lasting (20 to 24 weeks under normal conditions).  Designed as a one application preventer to be applied in mid March.  This product actually kills young crabgrass seedlings, so it's great if March 15th turns into April 20th.  Do not use a second application of any product with this material or you will eliminate falling seeding.

Team  - A combination of Balan & Treflan, this product is old and reliable, lasting 12 to 16 weeks.  Excellent for use in mid March as a one time general preventative.  Can be reapplied in mid May if you have had a crabgrass history, rendering excellent control.

Pendimethelin - Similar to Team.  Usually found in Scotts + Halts.

Tupersan (Siduron) - This product is unique in that it is safe to apply to newly seeded lawns or areas where grass seedlings are young and tender.  New seedlings will suffer damage from other crabgrass preventers.  Tupersan is short lived (4 to 6 weeks) and should be followed by a second application of  Team in after the new grass has established, probably in mid May.

    Many of these products come with or without fertilizer.  You may use either in mid March, but avoid fertilizing more than once, or later than mid April.  Additionally, you may be planning on using a post emergent "Weed 'n' Feed" in April for your growing broadleaf weeds.  Now you're feeding twice, promoting diseases and causing yourself to mow twice a week.  Post emergents are also available with out fertilizer.  I hope this information has been helpful and I encourage you to come visit us for all of your lawn needs.  Spring is upon us.