"Pink Torch" Puya
Fresh seeds are easy to germinate. Any small containers will work. You can use those plastic "6-pack" containers that nursery plants are sold in. For the soil i recommend a mix of 1 part high-quality potting soil and 1 part perlite, mixed well. Fill each container to within 1/2" of the top with soil. After filling the containers, water the soil so that it is uniformly moist, but not soggy. Place 1 or 2 seeds on top, and sprinkle a very thin layer of vermiculite or soil on top - just enough to barely cover the seeds, because the seeds need light to germinate. Spray the top soil with a spray bottle. Ensure that the surface soil does not dry out, perhaps by putting the pots in a propagation dome or plastic bag. Place the pots in a spot that's about 65-75 degrees, under a fluorescent bulb, or in bright shade. By the way, if you are inexperienced with growing seeds, start by planting only half of them.
Many of the seeds should sprout within 3-4 weeks, although allow up to 8 weeks for any slow ones. It's normal for a few seeds to be sterile and not sprout. Once you see little green leaves - celebrate - and then remove the bag or dome. Spray the soil whenever the top half inch of soil feels dry, but avoid keeping the leaves wet for long periods of time. A well-ventilated spot is best, to avoid rot. Give your seedlings either filtered sun, or 2 hours of morning sun plus bright shade the rest of the day. Transition them to more sun very gradually. About every 3-4 weeks, give them an hour more sun each day, until eventually they are in a half-day's sun, with some shade during the middle of the day. After about a year you can slowly transition them to full sun. It's best to grow them in a protected spot for the first 2-3 years, so you can keep an eye on them. Be patient with your Puya plants, as they are slow growers.
Long-term care: Water moderately whenever the soil is about 2/3 dry down where the roots are. I recommend using a moisture meter probe to monitor the soil moisture. You can buy this at garden and hardware stores for about $4. Simply stick the probe in the soil at the level where the roots are, and water whenever the needle is about 1 or 2 on a scale of 10. Avoid letting the soil completely dry out, but don't let it stay soggy either. Never let the pots sit in a tray of water. Feed once a month during periods of active growth, using an ordinary complete vegetable fertilizer at 1/2 the recommended dose. Remember that small seedlings need very little fertilizer. Most potting soil contains some fertilizer, so your seedlings shouldn't need feeding for the first 2-4 weeks.
Repot your plants to a larger container whenever the roots start circling around the bottom of the container or poke out of the holes. After a few years, move it to a 3-5 gallon pot. A colony of plants will need a larger container. Use cactus soil when you repot. Protect your plants from frost for at least the first winter or two. Also keep them fairly dry during the winter, unless temperatures are above freezing. They will bloom the soonest if protected from frost. During the summer, it's best to give them some mid-day shade if it gets into the upper 90s or above.
By the way, the leaves will develop a white powder on them. This is normal!
Have fun growing them!
Strange Wonderful Things