when to harvest

I am a newbie to vegetable gardening I was wondering when to harvest the following.
1.   Carrots
2.   Beetroot
3.   Leek’s
4.   Shallots
5.   Red onions
6.   Radishes
7.   Spring onions
All the above where planted out in the middle of April.

With all of these except shallots and red onions the answer is when they are big enough.

Leave red onions until the tops fall over and start to wilt, although the above applies if you need one for the kitchen.

When you can wriggle shallots and they come loose from the bunch they are ready to lift.

Both onions and shallots need drying carefully so that they store well. When you think they are dry then dry them some more.