Alminium foil and on top of the water heater--you probably cooked them. Seeds do not need heat to germinate like that. Bottom heat is used to warm the soil in pots and to keep the heat constant. By the time the heat reaches the seed it is only luke warm.

Are you sure the seed was ripe before you took them then. If you are then do the wet paper towel or coffee filter in a baggie and let them sit at room temperature out of the sun. Check them daily.

fordyford - I winter sowed six different types of hardy hibiscus back in February & March from seeds I got in trades. They're just beginning to sprout inside the milk jugs the past few days. I cut the top off one jug so far but the sprouts are still small and just beginning to send out their cotyledon/seed leaves. If you don't have any luck with growing them from seed this year, you may want to try winter sowing them next Feb/Mar and hope they sprout for you in May. I don't have any more seeds but will harvest next year's supply from whatever blooms I get this year. If I have enough to spare, I'd be happy to send you some in exchange for a SASBE. Feel free to email me if you have questions.
Eileen

Eileen,

How do you harvest the seeds from the blooms ? Thank you.

I removed the pods from the plant after they had turned brown and was starting to open. I stored the pods in a glass bottle until spring.

Any chance you can go to your former residence and dig up a volunteer? These reseed themselves so easily, it seems a shame to go through all this struggle when there are probably plenty of seedlings starting around the original plant.

Can you do this with all Hibiscus ? I've admitedly never paid enough attention, but we have a Hibiscus (red hot I believe it is called) and I'm fascinated at the thought of attempting to harvest some seeds.

cocoabeachlorax - after the flowers fade, seed pods will form. Once those turn brown you can harvest them. I dry them on a paper plate indoors for a couple of weeks before packing them away until I can winter sow them. They're pretty easy to grow from seed and don't need any special treatment. Other hibiscus I've grown from seed are rose of Sharon (hibiscus syriacus). Those grow a couple of feet the first season but they won't bloom for a year or two. Hibiscus moscheutos/hardy hibiscus may not bloom their first year either but they're sure worth waiting for! I bought my first plant last year--'Luna Blush'--and watched the flowers to see if they formed seed pods. Harvested the seed pods after they turned brown.
WARNING!!! Seed collecting can become habit-forming!

Digging up a "volunteer" is a good idea and a lot easier than what I'm going through. I'm sure the people at my former residence won't care since they're not into flowers like I am.

According to a couple sources (Prairie moon nursery website, William Cullina's book on native wildflowers), hardy Hibiscus species need 60-90 days of cold stratification to germinate. Winter-sowing would be an ideal way to start these from seed.

You could try putting the seeds in a baggie in the fridge for cold strat, but winter-sowing is so much easier. As would be digging up a seedling. :)

Interesting. I have 2 hardy hibiscus plants that are at least 10 years old, and they've never set any seedlings or volunteers.

I'm not surprised to hear the seeds are slow to germinate. I've rooted cuttings from my plants and they are the slowest things to root that I've ever worked with. Patience, patience... I've got several nice little rooted plants, one full year later.

Oregonwoodsmoke, maybe you don't have hardy hibiscus? I have a blue hybrid Rose of Sharon that looks and behaves identically to my hardy hibs, but the seed is sterile. Or at least it's never reseeded.

I've never been able to find seed pods on any of the hybrid rose of Sharon. My daughter has several mature bushes growing in her garden and they don't appear to set seed. The flowers just fall off the stems as soon as they're past their prime. The regular ROS have distinctive seed pods that are loaded with seeds. I harvested hundreds of them last fall. If anyone wants seeds, let me know!!! ;-p