I bought a tuber from a store and I am quite a newbie so I want to know what to do.
What soil do I use?
How big of a pot? how much water?
I also have a sunroom. Will it do best there?
What do I do to get it to flower?
Not that I always do it myself, but it's kind of a good idea to ask some of those questions before you buy it rather than after. To start--it's been more years than I care to think about since I grew a 'gloxinia' tuber. First, what is commonly known as gloxinia is actually a sinningia. When what is now the Gesneriad Society was started it was started primarily for people who grew gloxinias, as they were then known, so it's a pretty important plant! Have you started any other bulbs or tubers? I think when I used to start them, in a pot not much bigger than the tuber, I used to put them on top of the refrigerator 'til they started top growth--they get some bottom heat that way (tho' I'm not sure my energy star frig puts out nearly as much!) Be sure to give them good light as soon as that little furry bud shows up, and your sunroom would probably be fine; they need more sun than many others, which may be why they don't seem to be grown as often these days. Use a good-quality potting mix that drains well, feed them lightly periodically (I feed *very* lightly with every watering for most my gessies) and enjoy them as they grow and bloom. After they bloom and grow and all, and begin to slow down, let them go dormant. Don't think they're dying and dump them, as many have done! Don't force them if they don't want to. Let them stay dry and dormant until you see new growth, when they may need repotting--or may not!--and a new cycle of growth and bloom begins. Probably someone who's grown them more recently will have some better advise! Enjoy! They're beautiful plants!
I don't have much experience, but last year I started a few gloxinias from leaves, and I tried growing a couple of plants in a south window, and a couple in a north window. The ones in the north window grew leggy, and the plants in the south window were shaped very nicely. But by the time the south window plants were fully grown, with large leaves, watering became a real pain, sometimes I'd water them in the morning, and by the evening they'd wilt a bit (but they'd perk up just fine after watering). I do use well-draining soil (at least half perlite), so with other soils YMMV. I now have several tubers that just sprouted, and I will put them in the south window for now, so that the young foliage grows nicely shaped, and then, by the summer time, I will move the fully-grown plants into a bit less lit location. I guess an east window would be perfect, but I don't have one, so I'll have to improvise.
I put my tubers into 6'' pots -- the tubers are only about 2.5'' in diameter, but they grew to that size in just one year, and their 4-4.5'' pots were full of roots, so I figured they want a bit more space. That's just my guess though, I might be wrong. I remember reading somewhere that a bigger pot will give you a bigger plant -- which you may or may not want. (Maybe I should do an experiment, keep one of the tubers in a 4'' pot, see if the plant turns out smaller. That's a neat idea.)
And you don't really need to do anything special to make them flower -- as long as the plant is reasonably healthy, it will stick to its annual cycle: grow-flower-go_dormant.
My mother used to grow gloxinias in Conn. and I'd like to start growing them again although I'm out here in California.
Is there anyone who would care to share some tubers?
I can't find any store around here that stocks them. They all seem to say "Ohhhhhh" no, we don't have any.... I guess they're out of favor.
I remember the grocery stores would have LOTS of them for sale every year when I was growing up. It was one of those plants that were inexpensive to pick up that way and gave lots of enjoyment!
Love to start growing them again - then I can share them back!
Please let me know if you'd be up for an exchange or can just spare a few. Thanks,