The single Petunia of the garden makes an excellent winter-bloomer in the window-garden. It may not be quite as showy as the double variety, but it is far preferable to that, as it can be depended on to give flowers throughout the entire season, and that cannot be said of the double Petunia.
If you had fine varieties of the single Petunia in the garden in summer, select such of them as you admired most, and pot them in September. Cut away the entire top when you do this. Give them the same soil they grew in during the summer just ended. In a short time new branches will be sent up from the old roots, and almost before you know it the plants will have renewed themselves. Growth will be as luxuriant as if they were in the garden beds. Soon they will begin to bloom, and from that time until spring they will seldom be without flowers. It is a good plan to shorten the branches from time to time, thus encouraging the production of new ones, from which you will get larger and finer flowers than from those which have exhausted most of their strength in the development of blossoms.
The application of fertilizers, of moderate strength, will have a marked effect on the size of the flowers.