|I am going to have petunias in window boxes on a 2nd floor porch. The window boxes are 24 inches long. How much soil should I have in the window box and how many petunia plants can I put per box?
|Use a lightweight, well-draining mix that contains perlite, vermiculite and/or pumice. Fill the box so that when planted and after watering the soil level is about two inches below the rim. (Note that the soil will settle with watering.) Leave space between the plants for them to spread to their mature size. A spacing of about 8-10 inches should be adequate. Good luck with your window boxes!|