I sow in summer (May-August) from 72-85 degrees. IME seeds have short shelf life, buy from someone you know that has fresh seeds (CandD Plants is where I've gotten mine). Fresh seeds give me 50-70% germination, tends to be better using the Fleischer method instead of baggy. But either way has given me at least 30%. Most seedlings will appear near 2.5-4.5 weeks IME, and typically all at once or over 2-3 days. B. bruynsii takes longer, 2 months minimum. They will grow year round as seedlings if kept indoors under lights, and depending on species/type locality, bulbines can have a major dormancy or retain leaves but grow more slowly in the summer heat.

Thx, Ben. I know the "Baggie" method but can't say I've heard of the other... obviously, someone you know or has written about it here. I assume the purpose is to increase warmth and humidity. So you keep them moist and warm until they germinate like Adenium seed? You sow in a fine grit like pumice fines?

Fleischer method is similar to baggy, but done in an airtight container like a to-go container or mason jar. Soil is sterilized in-jar via microwave, which leaves the ideal amount of water if done correctly, which takes some practice IME lol. Major differences are how water is distributed throughout the soil and the sterile air, like you said. I'd say a little warmer than Haworthia germination temps (which don't do well for me in 80+) but no additional heat needed. I just put my jars on a windowsill. I use a complex soil for seedlings, works for everything from Ariocarpus to Trichodiadema for me: 40% Norlite, 20% Turface, 30% coco coir, 10% horticultural sand.

My Bulbine frutescens seeds just sprout everywhere all over the garden every winter. ;)