DIYbanter - View Single Post - topdressing & overseeding, and killing dandelions all at once

wrote:
I would like to to topdress my entire lawn with a new layer of topsoil
(half an inch) and overseed it, but I currently have dandelions that
are starting to grow. Quite a few dandelions actually. How do I
proceed to coordinate the need to grow new grass and kill off the
dandelions at the same time?

Why are you top dressing? How large is the lawn? Fairly healthy?
Compacted badly?

If I was putting major effort into an established lawn, it would be to
de-thatch, weed and fertilize. The dandelions should be attacked early,
and a broadleaf herbicide applied when they are young works best. Don't
always need to apply to entire lawn - can hit concentrations with a
hoseend sprayer or hand sprayer - depends on type and number. For
stubborn ones, painting on RoundUp with a brush is feasible if not to
numerous. Keeping the buggers from seeding, even to the point of
hand-picking, will help unless you are surrounded by dandy fields. If
the lawn is lumpy and uneven, top dressing might be done gradually
without hurting the growing lawn. You can't, as you said, apply
herbicide to new grass seedlings. Best weed "treatment" is prevention,
although seeds sometimes take 2-3 years to germinate, and always will be
carried in by birds and the breeze. Proper watering, cutting and
fertilizing will grow good grass that helps crowd out the weeds.