Tray grown wheat grass is nutritionally inferior to outdoor wheat grass. Many consumers of the tray grown wheat grass juice do not realize that it is made from wheat grass that has not reached its full nutritional potential. Tray grown wheat grass is grown under artificial conditions – usually in a warm greenhouse or indoors under fluorescent lightning. The grass is harvested and juiced only 7-10 days after sprouting, compared to up to 200 days for outdoor wheat grass. Therefore tray grown wheat grass does not have time to develop a significant root system. Instead the accelerated growth causes the plant to put most of its energy into growing leaves.
Tray grown wheat grass has a relatively high level of simple sugars compared to outdoor wheat grass. Because tray grown wheat grass develops quickly, it does not have the time to convert these sugars into complex carbohydrates, vitamins, enzymes and proteins. Furthermore, tray grown wheat grass is often grown with little to no soil. Very few nutrients are absorbed through the roots.