Firstly you need to prepare your growing medium. I always find that a good quality general purpose compost is most successful when germinating bamboo seed.
Fill your chosen pot or tray with compost and moisten it with water. Place the pot or tray into your propagator for 24hrs bringing it up to the required germination temperature (20 - 26 deg C). If you don't have a propagator simply cover the top of your pot with a clear plastic bag held in place with an elastic band.
Soak your seeds in tepid water for 24 hours. Make sure it doesn't get too hot, as high temperatures can kill your seeds. Cooler temperatures however, will not hurt the seeds, but may delay germination by a few days. Space your seeds out on top of your warm compost at 1cm intervals and sprinkle a further fine layer of compost on top (approx 0.5cm is enough).
Place your propagator in a location where it will get medium shade. NOTE: Wherever you put it, it should not get too much direct sun, even a mini greenhouse can quickly get up to seed killing temperatures in hot direct sun. Check on the propagator daily making sure that the compost never dries out. Before the seeds sprout, they can survive getting too dry once or so but as soon as they sprout, they can die in a matter of hours if they dry out. You may see a sprout within 10 days from planting, though the bulk of germination will occur after at least 15 or 20 days.
Different species have different germination rates, so don't get disappointed too soon. If any of the sprouted seedlings get tall enough to touch the plastic dome lid while others are still getting started, prop the lid up as necessary to prevent the leaves from touching it; Any leaves resting against the lid will quickly rot and risk killing the seedling.
After about 30 days, most of the seeds that are going to sprout with this method will have done so. Transplant all of the healthy sprouts into 4cm pots using the next few steps. (Don't discard the rest of the seeds yet, as a few more may bolt into action by changing their conditions). Mix a good potting soil with about 50% small bark-chip mulch. This makes a potting mix with very high drainage that is good for bamboo. Move each seedling into a pot and fill around it so that the neck of the seedling is level with the top of the potting soil. Give the pots a good dose of water. Because of the really good drainage, don't worry too much about over watering. Set these pots in an outdoor location that gets about 50% shade and that never gets full hot direct sun for more than a few minutes at a time. These seedlings are now well on their way. You will likely lose approximately 10% of them for no apparent reason at all, but the rest will have a good chance at making it to maturity.
For the first winter in cooler climates, the seedlings will need shelter. Plant the pots in the ground and give an inch or two of mulch. Don't give them more mulch than that, as it will encourage mice to move in and later to eat the top off of your bamboo. In really cold climates or for less hardy species, they may need to spend their first winter indoors or in a greenhouse. But remember that they need some water even in winter, so don't just put them in a greenhouse and forget about them!
During the following Spring consider 'potting them on' if you feel that the roots need some more room. Then simply keep moist, sit back and wait for your first bunch of new culms / canes. Once the seedlings have reached a height of approx 30cm their ready to be transplanted into your garden.
This is the basket Message
This is the basket Message