Are pre-emergents used by professionals better than the residential grade products you buy off the shelf?
The short answer is yes they are, and there are two primary reasons as to why:
1) Residual:
Residential grade pre-emergents are going to have a residual of about 3 months max. Professional grade products like Simazine, Prodiamine and Specticle Flo will give you anywhere from 3 to 9 months depending on how they are mixed. The longer the residual, the fewer gaps in coverage you will have. Products like Specticle that have a 9 month residual will actually give you overlap in coverage, meaning there is never a time when you don't have a barrier of pre-emergent killing weeds as they germinate.
2) Timing:
Residential grade pre-emergents HAVE to be applied BEFORE weeds germinate or they will not work. Professional grade pre-emergents will still kill young weeds, even if they are applied after germination.
All said and done, they simply work better, last longer, and give a larger margin of error with timing.
Here is a little industry secret...these products are available to purchase and apply by anyone, not just lawn care professionals.
The problem is:
1) The quantities some of them are sold in are not cost effective for homeowners.
2) While most can be purchased in granular form, liquid applications are the only way to get the most out of these products...and liquid applications are difficult for homeowners that don't have the right equipment (there is a video on this topic coming!)
