When should I pick my cucumbers?

You can pick cucumbers whenever they’re big enough to use. When the fruit starts to appear, check the vines daily, as the fruit enlarges quickly.  The more you pick, the more the vines will produce.  Don't let the cucumbers get oversized or they will become bitter, and don't leave overripe fruit on the vine (their production will slow down).  If they are yellow on the blossom end of the fruit, they have become overripe. 
To remove the fruit, cut the stem above the fruit using a knife or clippers.  Don't pull them off or you  may damage the vine.  You can read up more on this topic by clicking here.  Enjoy your harvest!  - Gardening Gal