I've done it both ways. However, it's best to have two sprayers & label one
for weed killers. While chemically there won't be any adverse chemical
reaction, you will be adding residual weed killer spray to shrubery and
flowering plants which could damage them. Also, a weed killer spray
container (generally one which attaches to hoses) should have a sprayer head
which sprays down onto your lawn while the general insect sprayer will have
a spray head which can rotate to reach up into trees, the underside of
leaves on shrubbery and other areas needed. I'd recommend the Ortho
dial-a-spray for the latter. Hope this helps.
"kaskiles" wrote in message
om...
Hi,

Can I use the same sprayer to spray both weed and pest control
chemicals? Or do I need to buy one sprayer for weed and one sprayer
for insects, because they might chemically react with any residuals
absorbed into the plastic sprayer? I would clean it out with clean
water after use.

Thanks.