This study was performed to investigate how to smoke solution affects dry matter loss, crude protein (CP) and toxic compound ODAP contents of grass pea in hydroponic media during seven days period. Three doses of smoke solutions (1, 5 and 10%, V: V) by diluting with tap water were applied to seeds as priming agent, and tap water was used as a control (0%). The experiment was arranged according to the split-plot design with three replications. Compared to seed, significant change was detected in hydroponic sprouts depending on the day in terms of dry matter loss and chemical content. Grass pea sprouts had higher CP and lower ODAP content than seed, even in control treatment. Furthermore, smoke solution increased the efficiency of system by increase CP, decrease ODAP content and also decreases dry matter loss, with significant effect on doses. CP of sprouts increased day by day and was the highest on day 6 (36.27%) at the 10% dose of smoke solution followed by 5% on day 7 (36.09%). ODAP decreased up to day 6 and then began to increase, but it was lower than control at all doses of solution during to experiment. This study showed that grass pea is suitable crop for hydroponic forage produce and that smoke solution can make a significant contribution to yield and quality of sprouts, especially at the dose of 10%. However, when the yield, nutritional value, and safe use were evaluated together, it was observed that the best time for harvesting was the end of the 6th day and delaying did not provide a significant advantage and even occurred undesirable results in terms of ODAP and dry matter.