A series of germanate glasses with manganese and alkaline ions (Li, Na, K, Rb, Cs) are successfully synthesized. Only 9 out of 21 studied compositions crystallize into glass-ceramics with LiNaGe₄O₉ and Li₂Ge₇O₁₅ nanocrystals. The glass-ceramics possess intense emission near 660-670 nm with 37% QY and two-exponential decay with lifetime equal to 1.29 msec. The fabricated materials can be used as a deep-red radiation light source for plant growth cultivation.