This study aimed to identify alternative raw materials capable of improving the physical and nutritional characteristics of substrates and maximizing productivity and functionality in response to the supply instability of beet pulp, a conventional supplement in Sparassis crispa cultivation. Various nutritional supplements (crushed corn, wheat bran, cottonseed hull, barley malt, pressed barley, and rice bran) were individually mixed with larch sawdust substrate to evaluate cultivation characteristics, yield, and β-glucan content. The pinheading period was 1 d across all treatments, except for the beet pulp single treatment (12 d) and cottonseed hull treatment (12 d). In terms of yield, the pressed barley treatment exhibited the best performance, with a fresh weight of 587 g and dry weight of 55.9 g, representing increases of 46.0% and 48.7%, respectively, compared with that of the control. The β-glucan content was significantly higher in the pressed barley (41.55%), beet pulp (41.25%), and barley malt (40.54%) treatments compared with that of the control (32.79%). Overall, although the conventional beet pulp single treatment accumulated high levels of β-glucan, limitations such as delayed pinheading and lower yield were observed. In contrast, the pressed barley treatment simultaneously achieved multiple advantages, including a short pinheading period, maximized yield, and high β-glucan accumulation. Therefore, supplementing larch sawdust substrate with pressed barley as a single additive is considered the optimal substrate formulation to effectively replace conventional beet pulp, shorten the total cultivation period, and enable the stable mass production of high-quality S. crispa.