Viewing post #3041274 by crowrita1

Any of the pre emerge applications...."chemical", or "green" won't draw either rats, insects, or mold spores...if they are applied correctly. In order to work, they need 'watered in"....both Preen, and Ornamec recommend 1 inch of water....not sure how much other brands recommend . The concept is this...the acrual chemical that stops the seed germination...be it a "natural" in the corn gluten, or the "synthetic" in Ornamec...degades, and loses it's "oomph" in sunlight....if I remember correctly (a real trick, at my age!) ...20 hours of sun exposure completely negates the effects of the pre emerge. So, you till, or lightly rake the surface of the soil (as much as exposed iris roots, etc. allow), apply the granules, and irrigate '''lightly...until you have applied the recommended amount of water....then, the "granules " aren't granules, anymore, they are dispersed into the top 1 inch (or so) of soil...and that's where they do their work.
If applied, and NOT watered in...or applied on compacted soil....when it DOES get around to raining, some areas will get "granule runoff" they will 'pile up" in the low spots, and, being "an organic substance" , and wet...they will mold. At least...that's what I've 'learned" , over the years.