Even though lupins have tall, spiky flower stalks over star-shaped leaves, they are in the same family as peas and other legumes and bear their seeds in pods. There are more than 300 species of lupin, and they've been cultivated for at least two millennia, with some varieties harvested annually and passed down through generations of families. Lupins are one of the simpler seeds to harvest, and the blue, pink or white blooms make the effort worth your while.
Pick the ripe pods from the lupin plants and place them in the paper bags. Put the pods from separate colours or varieties of lupin into separate bags. Label the bags.
Spread the pods in a single layer on the bench or tabletop. Segregate by colours and species, if applicable. Cover the pods with the cheesecloth and let them dry for two weeks.
Split the dried pods open along the seams and remove the seeds. Discard any that are mouldy or malformed.
Put the seeds in envelopes according to variety and colour. Seal and label the envelopes.
Store the envelopes in a cool, dry, dark location.
You can tell when a lupin plant is ready to harvest by looking at the pods. They should be black or dark grey but still firmly closed. The pods will feel dry and brittle and should "pop" open easily when you squeeze them.
Pods are ready to be picked when they snap off the stem; if they don't come right off, wait and try them again in a few days.
Healthy lupin seeds are about 7 mm (1/4 inch) in diameter, round or oblong and a grey to dark-brown colour.
If you store your lupin seeds in the fridge, put them in jars or tightly sealed bags to keep the humidity out.
Don't harvest seeds while they are wet. They will mould.
Cover the ripe pods with the cheesecloth as they are drying -- some of the pods will split as they dry and the seeds may pop into the air and be lost.