These are this season's new bulbs. Lemon Star and Spotlight put up a third scape after they were planted. So far, I am pleased with the pot, just an inexpensive plastic pot from Walmart with a loose good organic potting mix with a slow release complete fertilizer. Its in full sun now, but as it gets hotter, I can move the pot (with a refrigerator mover) into a place that gets a little less sun. In the winter,if we have a hard frost, the pot can be moved into the garage, otherwise a frost blanket thrown over the pot should be enough for a light frost. These bulbs don't need a great deal of space and a dozen fit in a good sized pot.
Margaret, I'm surprised to hear that the foliage is turning yellow so soon, you'd expect that at the end of the growing season. The only thing that I could suggest is pull the bulb, check the roots, perhaps cut back the yellow foliage and repot it and see if it puts up new healthy foliage. It could be a root rot which would need a fungicide.
