If you’ve seen the fall issue of Garden Making, you know editor Beckie Fox has been busy rooting cuttings from her succulent plants (see page 46). These late summer days are the best time for taking healthy cuttings of many other kinds of summer garden plants, and rooting them indoors. Once the nights grow cool, plant tissues toughen and stems harden, making them less amenable to establishing roots. Collect and propagate cuttings now to ensure the stem tissues are still pliant, well-hydrated and vigorous.
Have a look around the garden to see what plants might yield viable cuttings to grow indoors. My grandmother always took cuttings from her old-fashioned coleus, the kind with curled and ruffled edges, and these grew through winter in her kitchen window. It’s also possible to take four- to six-inch (10- to 15-cm) cuttings from the growing tips of tomatoes, and root them for indoor growing. Growing tomatoes indoors requires a sunny south or west window. They can be grown under plant lights, but natural sunlight with the full ultra-violet spectrum of light makes a big difference in quality of flowers and fruits (if you’re luck enough to get them).
Select summer annual plants (like pelargoniums and double impatiens) with healthy growing tips. Gently brush or blow away any soil or debris on the foliage. Be sure there are no signs of disease or decay, like dark spots on stems, or leaves with crisp, withered edges.
Use a new, one-sided razor blade for taking the cuttings. Select stems with an obvious growing tip showing new stem or leaf growth from the top. Cut each four- to six-inch (10- to 15-cm) stem piece on a 45-degree angle. If taking more than one cutting at a time, place each cutting immediately into a plastic bag and set it in a cool, shaded place as you move about the garden.
Fill new containers (or vigorously scrubbed recycled pots) with fresh soilless mix from a new bag. Place the pots in a pan or sink of hot tap water for 10 minutes and then set them aside to drain for 30 minutes.
With a pencil point, poke a 1.5-inch (4-cm) hole in the planting mix. Remove the lower leaves from the cutting, leaving two leaves at the top. Dip the bottom half of the cutting into powdered rooting hormone (purchased from a garden centre), and insert it into the hole, being careful not to knock off the powder. Gently firm the planting mix around the stem.
Place the containers in clean, clear plastic sandwich bags and leave the tops open for air circulation). Place them near a bright window, but not in direct sun. Check twice weekly to see if the planting mix needs more water. After three weeks, gently pull on a stem to see if there is any resistance – resistance means roots! When the cuttings are actively growing, pot them into larger containers and move into brighter light.