I would put it down as soon as possible. Watching for the forsythia to begin blooming is an indication that soil temps are about right for weed seeds to germinate. A little too early is always better than a little too late.

Get it down before the rain and you won't have to water it in. Read the directions on the bag--it probably says to water it in.

Thank you. Just checked weather forecast which now says 1-2 inches of rain tomorrow. Too heavy for fertilizer/pre-emergent?

It's too early for fertilizer, which will simply tap the roots of carbohydrates, set off massive top growth, and set up problems for summer.

However, that much rain is also a bit heavy for pre-emergent. Generally, recommendations are for 1/4 to 1/2" of rain post-application. I wouldn't gripe too much about an inch, but the possibility of getting 2"? Hold off.

Thank you. I am holding off until the next rain. Enjoy the spring!

Might be good to put it down after the rain and then irrigate to activate it. The crabgrass could start to germinate soon and you want to get it down before it starts germinating. If you're using Dimension that has some post emergent effect on baby crabgrass so maybe waiting until the next rain would be okay. If the forsythia is blooming, that's the sign to get the pre-emergent down.

Thanks everyone. I held off which worked out well because we got hit by a very heavy thunderstorm last night. Next rain is tomorrow followed by 60 degrees and sun for the next several days.