This section is from the book "Indoor Gardening", by Eben E. Rexford. Also available from Amazon: Indoor Gardening.
This is a standard plant in most window-gardens. It is a free and constant bloomer, and will give the best of satisfaction if given the right kind of treatment. It likes a porous, spongy soil, well drained.
Be sure to have the crown well above the soil, which should slope away from the plant to the sides of the pot. If the crown is even with the surface, and water runs in about it and stands there decay will be pretty sure to set in, and that means death to the plant. There are single and double varieties, ranging in color from pure white to dark crimson, violet, and pink.
Instead of carrying old plants over for a second season of flowering I would advise the purchase of your plants each spring. You can grow them from seed if you care to do so.