What happens to wheatgrass if it doesn't get enough light? Wheatgrass will grow very slowly. It does this because it thinks it is still winter (which it probably is), and wheatgrass only starts to grow quickly when it is warm and has plenty of sunlight--which happens in the spring.
Though you can grow wheatgrass with 10 to 12 hours of sunlight a day and cool weather, it definately grows really slowly. Additionally, you will most likely end up not getting your juice for a couple of days because your next tray is too small to be cut. If you are going to grow wheatgrass all year long (which I highly recommend), you should definately invest in a good grow light. The easiest kind of growlight to use is the kind that screws right into a regular light bulb fixture like this one. They are cheap too--about $10-$20, and will last at least a year. You can screw it into a clamp-on light fixture, and clamp it onto somethnig about 2 feet above your growing wheatgrass tray. If you have more than one tray growing, you can stack them vertically on a shelf, and set the light at a 45 degree angle so the light hits all of the trays. It is also a good idea to turn the trays around once a day so the grass grows evenly. If you are really gung-ho, or are thinking about growing on a large scale, you can set yourself up with some long fluorescent growlights. Have a good winter!