Posts Tagged ‘pre-emergent’

Weed Control: Pre-emergent vs. Post-emergent

Published by JKeefe on May 14th, 2012 - in Broadleaf Weeds, Lawn Care Companies


I have lots of folks asking the difference between treatments that claim control over annual broadleaf weeds, or pre-emergent weeds like spurge, vs. post-emergent weeds such as dandelions.  While this is often a very confusing distinction, a brief explanation will clear things up and differentiate between the two types of weed control.

Annual broadleaf weeds germinate beginning in late April and continue throughout the summer.  The early season crabgrass suppression treatment not only inhibits crabgrass, but these annual broadleaf weeds as well.  Therefore, these weeds don’t even germinate because of this first treatment in many lawn programs.  However, this type of treatment will not control existing weeds like dandelions or clover.  A subsequent treatment which targets these perennial or biennial broadleaf weeds works completely different by attacking the plants you see in your lawn right now.  This is done by contact with the leaf surface and by absorption into the root system.

Although there are some annual broadleaf weeds which will germinate later and not be controlled by the first treatment in April or May, subsequent weed treatments in a post-emergent setting will address those villains.  Another option to naturally reduce both annual and perennial/biennial broadleaf weeds involves turf building by adding compost tea, kelp, annual aeration/overseeding, lime, as well as natural or organic fertilizer.  A healthy lawn that is thick and growing will naturally crowd out a huge amount of weeds over time without the need for broadleaf weed control treatments.  However, many folks like to speed the process up by having a few select weed reduction treatments followed up by a conversion to natural treatments afterward.

So, if you are confused about pre-emergent weed control versus post-emergent weed control, I hope you feel a little better after reading this short blog post!  Have a great spring and don’t fear, “Mrgrass” is always near!


Time to review and renew your 2011 lawn care program

Published by JKeefe on January 3rd, 2011 - in Lawn Care Companies

The winter months bring back not so distant visions of once green lawns and surrounding trees.  As odd as it may seem, scheduling any kind of lawn program while snow is on the ground is actually a sound process.  There are many good reasons to activate a lawn or plant health care program during the winter to insure prompt service once mud season arrives. 

Review your lawn proposal this winter

The weather plays a large role in the spring as to what and when certain treatments can be done- mostly due to temperature and moisture.  High heat speeds up insect, weed, and disease development- in some cases by weeks not days.  While this may not seem of great importance, temperature plays a huge role in advancing or retarding certain pathogens, ultimately affecting your landscape.  If you do not have a program “online”- ready to go- this timeframe can easily be missed.  Cold weather can slow down the ability of your lawn to recover and green up fast.  The later the first application of fertilizer, compost tea, or lime is applied, your grass is missing vital time for improved color and recovery from winter damage.

I have seen several years where the temperature rose into the high 70’s to lower 80’s in April and May- making some types of weed control applications harmful to turf without proper precautions.  The same can be said about not scheduling early plant health care sprays- you simply miss the window of opportunity for obtaining decent results on a variety of insect and disease issues.

Moisture content can wreak havoc on turf and shrubs in the spring- especially if the spring is cold and rainy.  Such weather greatly advances snow molds and leaf spot on turf while creating apple scab on fruit trees.  Low moisture can reduce seed germination without proper irrigation if aeration and overseeding are done in May or June.  Having overseeding or aeration already scheduled during the winter insures they can be completed at the proper time frame in the spring since they are already booked.  A great green care company will watch weather trends and activate services during the appropriate time frame- you deserve this kind of service.

Timing is the third reason to have your program already setup during the winter.  Many applications have a narrow window of opportunity and if missed, results suffer such as pre-emergent crabgrass control or broadleaf weed control.  Soil temperature and timing are very important on these kinds of applications.  If you think you may remember to call- it may already be to late- spring is a crazy time of year.  Another fabulous reason to schedule your green care treatments during the winter includes a signing bonus if available or a prepay offer for sending in the contract early.  Look for these kinds of financial incentives in addition to a high quality- diversified green care company.

If you have not read the “researching a lawn care company” series on this blog- be sure to check them out since they were statistically the most read in 2010!


Pre-Emergent Crabgrass Control in NH: The Coin Has Two Sides

Published by JKeefe on April 18th, 2010 - in Crabgrass, Lawn Care Companies

Baby crabgrass plant

If you have a lawn service or are preparing to treat the lawn yourself, you will likely want to consider pre-emergent crabgrass control now until mid to late May depending upon your location in NH or VT.  There are both positive and negative aspects of applying a pre-emergent in the spring depending upon the condition of your lawn, your future plans, and past issues.

The Good:

There are many types of products available and most not only reduce annual crabgrass, but also can help suppress other grassy weeds and summer annuals.  I often have a lot of clients point out rough looking grass in the early spring- saying, “See there…. my lawn is loaded with crabgrass!”  Well, crabgrass is an annual and does not even begin to germinate until late April through May (geographic soil temp) so any grass you are viewing now, is a perennial meaning it is there to stay.  Crabgrass usually germinates along the road or in bare areas that warm up first; you can see the little green sprouts with a little scouting like the one pictured above.

If your lawn has never been treated for crabgrass, depending upon the density and current condition, you may want to have a barrier put down to reduce this aggressive plant.  Left unchecked, crabgrass will thrive and take up vital lawn space- winning the battle while drawing upon space, water, and nutrients- leaving less for your desired turf grass.  Yes, like an older brother that gets most of the dessert and dinner, standard turf grass is not genetically adapt to thrive in the presence of crabgrass- a superior plant.

Crabgrass control also helps reduce summer annuals which can also be a bonus in a weak lawn.  I say suppress because many homeowner’s think crabgrass control is 100%, nothing could be further from the truth.  While a pre-emergent can help suppress the noxious plant, it breaks down over several months and will never stop growth in bare areas.  This brings me to my next point- the condition of your lawn- what is the current condition?

If you have large bare areas along the driveway, or sections completely absent of turf- I would urge a different course of action such as reseeding or perhaps some light renovation.  While most lawns can be treated and improved “as is”, there are many that simply would benefit more from the addition of loam or compost instead of a chemical barrier that will fail in weeks anyway under such stress.  My turf division offers light renovation to complete lawn installations- unlike the big National chains that do not.

The Bad:

Most crabgrass barriers, once applied, will remain in effect for about 2 to 3 months maximum depending up culture practices (mowing/watering) and the overall lawn density.  This means no seeding because most products inhibit not only crabgrass, but your seeding work as well.  Again, the best offense is a great defense- in this case, turf density.  Superior lawns take hard work; they arrive from turf building by mulching your clippings and applying fertilizer on a regular basis.

If you are unsure which course of action to take, don’t flip the coin and decide yourself, call up an expert like me and I’ll take a look.  If you live outside of my service area, send me an e-mail with a picture or call up a local lawn company with a good reputation.  Whatever you do, don’t call up the large National chains since they are in the business of applying tons of crabgrass control and cannot offer any renovation work should it be required. In addition, their sales force does not have the agronomic experience or training necessary to make an accurate diagnosis.  Enough said.

Good luck and have some fun making your lawn look great this year.  We don’t have many months to make an impact in NH, so don’t wait around- get a game plan and move forward!  Information is power.

Crabrass has a lighter green color

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