Cranky Man’s Lawn Epistles ’12: Good crab – Bad crab

Ah yes … The Summer season is officially upon us!  And as we settle in for three months of hot temps, cool surf, outdoor parties and traditional Summer foods, it’s important that we not forsake the home turf when those hot temps hit.  I will assume that if you have gotten this far without closing your browser, that we are on the same wavelength!

Remember these summer lawn tips:

  • If you haven’t started already, now is a good time to raise your mower settings to allow your lawn to grow longer.  This will help to prevent some of the damage a hot, dry summer can cause by keeping your grass-roots shaded a bit from the searing sun.  And even though we have been getting plenty of rain in May, damaging heat is right around the corner.
  • Once temps start to rise, don’t forget to water your lawn!  Once these May rains end and the heat starts to build, it will not take long for your lawn to dry out.  Making sure your lawn gets water every 2-3 days is crucial.  Blah blah blah … You get the point.
  • DO NOT apply fertilizers to your lawn when it has been hot and dry for some time with no relief on the horizon.  Chemicals that sit on a lawn without water is a recipe for disaster!
  • And finally, enjoy your blue crab, your soft crab, your King crab this summer, but get the crabs out of your grass!

Vile weed, CRABGRASS!

Late May to the first week in June is the most important time for crabgrass treatment.  In previous posts, I put forth my objections to the long-held belief that crabgrass treatments are best applied in the early Spring.  Many lawn supply stores will recommend one treatment in the early Spring to prevent crabgrass from germinating.  But even if crabgrass plants successfully germinate in March or April, the plants will not grow until the heat of Summer hits.  Crabgrass likes it hot!

So there are two theories on crabgrass treatment … The preemergent treatment that attacks the germinating crabgrass plants, and the postemergent treatment that attacks crabgrass as it gets ready to bloom.  (Of course, your lawn supply store will say you need BOTH.  But that’s not always the case if your lawn is in very good condition.)  If your lawn is in poor shape or has a recent history of significant crabgrass, then treating BOTH ways is probably the safe choice.  However, if your lawn is healthy and full, without a significant crabgrass issue, then I recommend an active crabgrass treatment applied just before the heat of Summer activates the growing cycle.

These are the choices that have worked for me.  Your mileage may vary!

I never really liked the preemergent route because it relies on a bit of “soil whispering” which many of us non-professionals is pure guesswork.  Soil temps must hit 55 degrees for several days in a row for crabgrass germination to start.  And who has that kind of precision when it comes to weather prediction and taking soil temp readings???  Not I, I can assure you.  If you know someone in the turf business (No, not the kid at the Lowe’s Garden Center!), they might let your know the perfect timing if you call frequently enough.  So I opt for the simplest way to treat crabgrass, just as I do other weeds.  Wait for the suckers to be there with no doubt and then bring down the wrath of chemical warfare!

I’m also frugal (cheap), so I prefer the one-and-done method of crabgrass eradication.

The trick is timing it right to give your lawn the full benefit of crabgrass protection.  If applied in late May-early June, most crabgrass treatments will be good for three months.  (The reason I avoid early Spring preemergant applications.)   An application now will carry you into late August-early September when temps will cool (i.e. not the best temps for crabgrass growth)

Use a post-emergent product even if you do not see active crabgrass plants.  Preemergents will only work on germinating crabgrass plants.

Here are some other good anti-crabgrass tips:

  • Keep your grass longer!  (Yet another benefit of letting your grass grow longer in the Summer.)  Crabgrass seed need direct sunlight to grow.  Longer grass will keep the soil shaded, frustrating crabgrass growth.
  • Reseed any bare patches.  Similar to the above line of thought, a bare patch with direct sunlight is an inviting bed for crabgrass growth.
  • Water LESS frequently, but for longer durations.  (Not a big fan of this suggestion from an overall lawn health angle.  But if you have an active crabgrass problem you might want to consider this).  The theory is that crabgrass plants have shallower root systems, so frequent and quick watering benefits the crabgrass.  On the other hand, healthy grass-roots are longer and deeper, so less frequent watering that run longer will benefit the good grass, not the crabgrass.  (I can’t say I buy this idea, since ANY watering has to benefit the crabgrass.  So what difference does it really make?  You will have to make this call, based on the condition of your lawn.)

Finally, I share the following link for the Purdue University Turfgrass Science program. 

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