animaux expounded:

Weed and Feed products are, for the most part, pre-emergent chemicals.

No they aren't, they're full of weedkiller to knock off the
dandilions, plantains, etc. Pre-emergents are a totally different
product, albeit with fertilizers, sometimes, that are applied earlier
than the weed and feed products. If you use weed and feed around here
in March it'll do nothing but spread unnecessary chemicals and
fertilize the lawn (excessively). Fertilizer with crab grass control
is spread then. The weed and feed comes in the second feeding.

At least that's how it works on chemical feeder's lawns. Not mine.

--
Ann, Gardening in zone 6a
Just south of Boston, MA
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