Expert: C.L. Fornari - 9/19/2007

Question
Hi. I have had my petunias for whole summer. It has been amazing having them, but now, as autumn is on the doorstep and temperature had fallen rapidly, I don't know what to do with them, or even how long can I leave them outdoor? Thank you

Answer
Agi,
Petunias are pretty cold hardy, so they should keep going for you until a hard frost.  If you want to save them for next year, it's best to do so by taking cuttings now rather than bringing the entire plant indoors. Know, however, that both cuttings and entire plants are prone to insects inside the house - especially white fly.

If you want to try saving cuttings, clip off ends of the stems that are about 5 or 6 inches long. Remove any flowers and the leaves on the lower 4 inches of the stem.  Dip the stem in rooting powder, coating the entire lower 4 inches you have removed the leaves from.  Have MOIST NEW potting soil or seed-starting mix in clean pots, and make a hole in the potting medium with a pencil. Stick the cuttings in the holes, one per pot, pressing the soil mix around the stem. Water well and cover the entire pot with a plastic bag that is allowed to be loose around the pot so that moisture is held around the plant but air can flow in as well.  Keep pots in a bright but NOT SUNNY place for two weeks, then remove the bag and watch the plants in this location for another couple of weeks. If they look strong after those second two weeks, move them into a place where they get more sun and overwinter them there. Or you can put them under florscent "shop lights" hung about six inches above the plants.  Water when dry, and in February clip them back by about half and start to fertlize.  Pinch the growing tips to keep them bushy.

As you can tell, it's alot easier to just buy new ones next year, but many people enjoy the challange of saving cuttings.  Use insecticidal soap on any insects that appear - Yellow White Fly Traps are also good - find them at your local garden center.

I hope this helps!
C.L.