You should be OK. If you want to give your soil everything it needs, then give it some compost. Labor intensive, I know, but there is no substitute for good compost in an organic program.

Yesterday, I sprayed molasses and compost tea on my yard. Last night we had rain and it is supposed to rain off and on, all day. My question is whether I will need to reapply after the rain? If so, should I wait until the soil dries out some?

You should be fine, the rain just watered it in. Severe runoff might be bad, but not showers and on-and-off rain.

Ideally how long after compost tea application can we turn on watering ?

-LG

Ideally how long after compost tea application can we turn on watering ?

About thirty seconds. ;-)

You might want to leave it until the dampness dries on the grass blades. Any nutrients the blade will pick up via foliar feeding are absorbed while it's damp. There aren't many direct nutrients in a compost tea, though. You're mostly applying it to add microbes to the soil.

Most microbes dislike ultraviolet light (although they can and do protect themselves very well). Watering them in starts their journey through the soil, so doing it immediately isn't going to hurt.

What about chlorine that will be in the water. Will it not reduce the bacteria ?
-LG

I believe as far as the chlorine its good to let the tap water pump for a day before adding the compost or try using rainwater. Around here we've definitely had enough rain.

For watering in, volatile chlorine leaves the tapwater before it hits the ground (most of it, anyway).

Non-volatile chlorates (I think that's the right word, but know there's a much more complicated one!) don't evaporate.

I've found some minor indications that humates bind them and render them harmless. If you're worried about it, add humate to the water you're using to irrigate.

However, most of us do irrigate and we don't lose our bacterial populations. It doesn't seem that tapwater is all that harmful to them.