If it's clumpy, put it on a tarp, smash it up with the lid of a bucket and let it sit in a place with no wind (inside if need be).. Don't make it harder than it is.
It would be helpful if you let us know what you were trying to grow.
It's pretty alkaline.
If you have acid soil it could bring it towards a neutral ph. If your soil is already alkaline, putting wood ashes on it will exacerbate the problem.
Anyone know what will happen if too much is added? Seems to me I read somewhere that you weren't supposed to add very much but never did say what would happen if .....I had some waiting to go into the garden and the lid blew off, it all got wet and so ended up coming out in soggy lumps. If this is going to cause problems what can I add to try to compensate?
If you don't want to change soil pH too abruptly, I recommend adding it to material to be composted or adding it to soil and then mulching on top so the pH is buffered.
The growbox has grown energetic squash (masses of flowers but almost all male last year but it was a very cold wet summer) and tomatoes and peas have done well in it. Had a wonderful bunch of baby dandelion tonight out of it. I have 4 of them going but every one is slightly different.depending on what was available. I have absolutely no idea about the ph. I wanted to try growing corn this year. Have I messed it up?