Wash the seeds in soapy water, followed by a ten minute soak in a solution of 9 parts water to 1 part household bleach. Rinse.
For seeds that have been stored, soak in clean water from one to four days. Change water at least daily. Seeds that remain floating are considered hollow, or otherwise incomplete, and unlikely to germinate. Seeds that sink to the bottom should be okay. Use these as you continue with the next step.
Place seeds in sealed plastic bag with barely moist vermiculite or peat moss.
Place sealed bag in a warm area of the house(not in sun), check them every week to see if the root has emerged, and ensure they remain moist (but not wet!)
Leave them in the warmth until the roots appear (anywhere from a few weeks to several months).
Once roots appear and are about 3cm in length, move the bag to a cool location. Temperature should be approximately 4 degrees C. (An old refrigerator is fine)
After 12 weeks, remove the bag and pot up the partially germinated seeds in a soil-less germination mix.
Depending on the time of year, you may have to place seedlings under grow lights for a few months before being able to transfer outside.
Keep seedlings under grow lights and ensure they are moist but not soggy.
Apply a balanced liquid fertilizer every few weeks.
Transfer outside slowly as you would any other tender seedling. Too much sun, too rapidly, will result in burnt foliage.
Seedlings should be outside in a sunny well-drained seedbed by September at the latest.