This study was carried out to determine the silage quality, in-vitro digestibility, energy content, and relative feed value (RFV) of the lamb's quarters (Chenopodium album L.), which was harvested and ensiled in three different vegetation periods. Raw nutrient levels, in-vitro digestibility and energy contents, Fleig scores and RFV in the silages; pH, ammonia nitrogen (NH3-N) and volatile fatty acids (VFA) concentrations in silage liquids were determined. Silages had the lowest DM (24.01%), NDF (44.07%), ADF (28.14%) and pH (4.70) with the highest CP (14.45%), AA (6.50%), RFV (141.50), DMD (69.43%), OMD (66.00%), DE (2.91), ME (2.39) and NEL (1.50) values at the beginning of flowering; the highest LA (3.01%) was in the mid-flowering period; the lowest CA (9.51%) and BA (9.51%) and the highest EE (2.92%) values were determined during the seed setting period. For all these silage parameters, the difference between the groups was significant (P<0.05). Despite the high protein content of the lamb's quarters and the silages made without additives, a satisfactory level of “good” quality class silages were obtained in all groups with all the parameters determined. It has been concluded that the silage will be of higher quality, especially in the periods between the beginning and middle of flowering, and especially if it is ensiled with an easily soluble carbohydrate source.