wood ash and fine shreddings

An interesting area, soil is something I'm starting to take more seriously. I'd say yes they're both good but only when mixed well with soil./compost.
I shred all my waste for my compost bins and would add wood ash if I had some.

A sprinkling of wood ash over the soil is good as it adds phosphate to the ground. Shreddings are also good for an overwintering mulch that can be dug into the soil at the end of the winter. As with most good things - use in moderation.

Bulbaholic' you are spot on once agine' cheers

Particularly good if your soil is acidic - good in moderation if neutral - not so good if alkaline as it can inhibit the uptake by plants of other nutrients.

As the shreddings rot down they may use up any nitrogen that is around so you may need to supplement with fertiliser.

I used to use both wood ash and shreddings in the bottom of the snap-pea and runner bean trenches I always dug in the autumn and left open ...for convenience (!) ...as I then added all the kitchen veg scraps through the winter - until spring when I topped it off with a layer of well rotted manure (this was before the foot and mouth caper - when you could still get the stuff) I had runner beans and peas like never before!!!

Does your husband mean to grow plants in pots? As in potting compost? Because if he does, the answer's no, it won't work for that. All the other uses everyone's mentioned above are fine, though.