To everything there is a season … and fall—especially late fall—is not the best season for plant propagation. Whether it’s seedlings or cuttings, they’ll get a very slow start when days are short. And that’s because they’re receiving mixed signals.
When you put seeds or cuttings in contact with moist soil, you’re sending the signal “get growing!” But between mid-October and the end of February, under the influence of short days, Mother Nature is sending them exactly the opposite signal. “Take a break,” she’s saying. “This isn’t the time to put on growth!”
The result is seedlings that either don’t germinate or do so only very weakly and that then grow only very slowly if at all. Or they etiolate (stretch for the light). Cuttings just sit there, hesitating to produce roots. In both cases, rot often sets in.
An Artificial Summer
If you want to defy Mother Nature and propagate plants off-season, use artificial lighting instead.
Place your seedling pots or cuttings 15 to 30 cm away from a fluorescent or LED lamp and set the timer to 12 to 16 hours. It’s also best to cultivate them “under glass” (that is, under a dome or inside a transparent plastic bag), because the air in our houses is very dry in winter and starting them under glass will create a beneficial “greenhouse effect.”
With long days and good humidity, you’ll easily be able to convince your seedlings and cuttings that spring has sprung and therefore that it’s time to grow. Furthermore, their growth will be fast and robust.
Once growth is well underway, gradually remove their covering, increasing the humidity with a humidifier or a humidity tray, but keep the plants under artificial light all winter if possible, at least until the beginning of March, so they keep on growing.
Yes, sometimes you can fool Mother Nature … and gain a substantial advance on spring at the same time!