There is a perfect moment when to juice Wheatgrass. The grass is at the perfect height and is dark green in color. Your grass should look something like the following:

My rule of thumb is your grass should be 25cms tall from the base. This may vary for some of you but I have found this to be the best height to juice wheatgrass. If you want to make your grass darker then I suggest using a good fertilizer or natural worm juice fertilizer on your wheatgrass