Rinse ½ cup lentils, remove any stones or debris, and place in a quart-size sprouting jar or other sprouting container.
Add 2-3 cups water, filling the jar three-quarters full; cover jar with a sprouting screen or mesh sprouting lid. Soak lentils at least 8 hours or overnight.
Drain and rinse lentils thoroughly. Invert the jar over a bowl at an angle so that the lentils will drain while still allowing air to circulate.
Repeat rinsing and draining 2-3 times per day until sprout tails appear. Taste sprouts (not lentils) daily; discontinue rinsing and draining when sprouts have reached desired length and flavor.
Drain for several hours before cooking or transferring to a covered container.