Sure you can. In fact many consider weathered straw to be even better to use as it is already decomposing and providing some nutrients. Any mold quickly dies off once exposed to the air and sun.

In your zone I would think it is a bit early for heavy mulching. What are your soil temps? Down here it is usually early June before my soil is warm enough for anything but very light mulching and with all the rain and cooler temps this year it will likely be more toward mid-June for me.

Just something to consider.

Dave

Thanks Dave,
I didn't want to put it down yet, but we're expecting rain every day next week. But it's supposed to be warm. So I was thinking the soil will warm up soon enough, and all that rain splashing the soil up on the tomatoes might be worse for it than cooler soil temps. What do you think? I need to do it this afternoon if I decide to go this route.
Thanks again!

I never put all my mulch down at once anyway. It is built up in layers over a couple of weeks. So you can start out with a very thin layer now right around the base of the plants before the rain to reduce the splashing and leave the rest of the soil bare to continue warming.

Remember that air temps are not a valid indicator of soil temps. Soil will always be at least 10-15 degrees cooler than air and usually more.

Dave

Thanks Dave. That's a great idea! I will put just a thin layer down today and add more as the temps stay up. Thanks!!

I go around collecting straw bales after Halloween (people buy them for decoration then toss them; wasteful) and they sit outside all winter and spring until I'm ready to use them. At which point I break the bale open, spread out the straw to dry for a bit, then run over it with the lawnmower. Chopped/shredded straw stays in place better for me.

Rodney

Good idea Rodney!