Me? I'd keep the old straw right where it is and just push it apart to make little holes to put the starts into. Then your garden is already mulched. The straw will break down little by little and feed the soil. I use hay mulch and treat it like this -- but the hay breaks down almost completely each year (quicker than straw) so I have to replenish.

To avoid any diseases that might be in the plant debris, just be sure to rotate your crops. Since different families of plants are susceptible to different diseases, if you plant something different in a space with plant debris, chances are the new plant won't be able to "catch" anything in that location. That's the way I understand it, anyway.

I'm sure others will weigh in on this, but that's what I'd do.

If I need to use new straw, what do I do with the old straw (it's a lot of straw!)?

I recommend new.

In a traditional, in-ground garden that old straw would most likely be tilled in or turned under into the soil to improve the soil and new mulch laid down after planting. That is what I do.

In cooler climates where mulch can only be applied later in the year, or when using raised beds, many will rake it all off the garden to allow the soil to warm well, use it as a compost pile for working into the soil in the fall, and mulch when the time was right with new straw.

So both those approaches would work for you given the size of the garden.

The reason I don't recommend re-using old mulch is because of the possible diseases, pathological fungus, bacteria etc. as well has the pests is could now harbor and like you, my winters simply aren't cold enough to kill them.

JMO

Dave

I'd compost the old straw in a hot pile and use when it's transformed. If you're organic.......you surely have a compost pile.

Thanks, everyone, for your feedback. Using new straw sounds like the smartest thing to do although it's a shame since the current straw is in great condition.

Dave... if I work the straw into the soil now, will it be okay to plant in? Won't it rob the soil of nitrogen as it breaks down?

I do have a compost pile but it's no where big enough to accommodate all that old straw. But I'll just start another compost pile.

At the end of this season, you might cover the beds/straw with cardboard and a layer of compost, and keep it wet. It will help to decompose/compost the straw in place for next season.

I gardened in Menlo Park Ca (bay area) for 45 years. I didn't really use mulch, I should have I guess. I dug compost in. I don't think that disease is much of an issue in the bay area. I would rake the straw off. Then because you have heavy clay I suppose I would double dig your planting areas and put some straw back with the plants or regular dig and put all the straw back.

Dave... if I work the straw into the soil now, will it be okay to plant in? Won't it rob the soil of nitrogen as it breaks down?

It can, not rob but bind it up, depending on how decomposed it is. But the assumption is that you will be tilling it is well before planting and that you will be adding additional sources of nitrogen anyway. If planting immediately you would definitely need to supplement the nitrogen levels.

Dave