Use of wood ash instead of lime?

We are fairly new to gardening so hope this question is not too basic.

According to our book, it is suggested the part of the garden for legumes be limed in the autumn. While we can buy lime here (it is also used to paint trees white at the bottom) we are not sure if it suitable for horticultural use so last year used wood ash from our log burner instead, spreading it out at about a bucket per 10 sqm during the winter (3 buckets in all). The crop yield seemed ok. Our soil is heavy clay but not sure if it is acid or alkali or if the ammount used was appropriate.

My question is : is it suitable to use wood ash instead of lime or should I bin the ash and try to fins suitable lime?

Wood ash is more of a source of potash than lime, although it does contain both, and as SW says it's easily leached out by winter rain.

Better to store it somewhere dry and use it as a top dressing next year - if your soil does need lime (best to do a pH test first) then powdered limestone or slaked lime is the best stuff to use (you could use quicklime or burnt lime at a pinch but it needs caution as it reacts with water and gets a bit hot so not something to be chucking about on a wet and windy day!)

Thankyou for taking the time to reply.

To address the points made : The book I followed was in fact the five year crop rotation plan from this web site "Lime Follows Potatoes, Then Legumes" 

I suspect our soil is ph neutral as cabbages grow just as well as tomatoes/potatoes, but agree I probably should undertake some tests to find out for sure.

We obtain wood ash in decent quantities as the woodburner is our only means of heating the house in winter, rather than throw the stuff out I thought it may be a possible substitute for lime due to its alkalinity...looks like I was wrong.