There are a few different herbs for male health that can increase sperm count and overall male fertility. All of these herbs can be used in a herbal tea.
Ginseng (Panax ginseng) - Known as a male tonic (an agent that improves general health and fertility) and used to increase testosterone levels and sperm count. The recipe for Ginseng Herbal Tea can be found using the link above.
Sarsaparilla - Known as a male tonic for increased virility and sperm count.
Saw Palmetto - Known as a natural viagra, Saw Palmetto can increase male libido.
A herbal tea made of a combination of these three herbs may help you to increase your sperm count.
Hope this helps, you also may want to consult a herbalist for a custom herbal tea blend.