Depending on what worms you want, I started a wormery by using a plastic dustbin and three or four 25ltr plastic bins wiv lids
the dustbin gets all the veg waste and the like (tea bags) from the kitchen. Initial composting is done in the dustbin, it's then put into the 25ltr bins for secondary composting and this is where I harvest my worms. You have to make certain the bins don't get too hot or dry,I also drill holes in the base of the bins to allow excess water to drain, I know it seems a lot of bother but it can pay of. Any worms left over from fishing get put in there, along with any found crossing the path while walking the dog after dark. Actually that is a brilliant way to collect worms, take the dog for a walk after dark in the evening, particularly if it has rained, tuck a bait box under your arm and any form of indentification that proves your an angler, (its a long story involving the police a young lady and a nasty accusation)
Search areas near where the path joins the grass verge, you will find a large number of worms congregate around the base of street lights for some reason. you will also find them crossing the path and on the road, (be careful not to get run over)do not worry about getting mugged because anyone seeing you will think you are either mad or a pervert peeping tom!!
All this costs a bit of time and is FREE, not only that your misses gets free compost for her pot plants!
Rather than the washing up treatment, which can 'damage' the worms, try just inserting garden fork and wiggling around. This should make a grating noise on the underlying sand/gravel/stones. Systematically move backwards and repeating and you will find the worms literally zoom out - just pick them up. Doesn't damage the lawn either.
The Pilgrim is right.
The best way to start a wormery is to put all your waste in a dustbin and transfer it to smaller boxes later.
I even put mashed potato in my wormeries (the worms love them) try it and you will see.