Top tips for growing plants from cuttings
Growing from cuttings is a special class of propagation that allows you to cultivate a new plant by using a trimming from an existing plant – essentially creating a clone. This method is most commonly used for flowering, aromatic culinary plants such as mint, marjoram, sage, rosemary, thyme, hyssop and lavender. These plants have naturally occurring growth hormones that allow them to create roots from broken stems. It’s like a lizard regrowing its tail – only in this case, it is like another lizard growing from a discarded tail. Cuttings are robust and much faster than growing from seed. This process allows you to quickly multiply your plants without costly trips to the nursery.
Many herbs are dormant over winter and do all of their growing from spring to autumn. Therefore, when we propagate cuttings it is good to start before mid-summer so that they can soak up as much light and warmth as possible.
1. Choose healthy, mature plants from which to collect your cuttings. We’ve had our best success with new growth, so look for young, green stems at the tip of each plant.
2. To test whether the stems will be effective, a ‘bend test’ suffices. Simply bend the stem back on itself – anything that breaks before turning 90 degrees is too woody. Anything that can turn 180 degrees back on itself without breaking is too young. You are ideally looking for snappage to occur somewhere in between.
3. Collect a number of cuttings approximately 20 cm (8 in) in length.
4. Once you have enough cuttings collected, strip the bottom few leaves from each one. Removing the leaves exposes nodes along the stem, from which new roots will grow.
5. These plants all have naturally occurring growth hormones that help cuttings to regenerate. However, some gardeners will use synthetic hormones to help stimulate the process. Gel and powder rooting hormones are available at most hardware stores and nurseries. Another option is to dip the plant stem into honey or cinnamon, both of which are known to work as natural root stimulants and are easily found in the pantry.
6. Any free-draining container filled with organic potting mix or seed raising mix can be used for sticking – the technical term for planting a cutting. Be sure that the depth of the container is more than 10 cm (4 in) and drains freely. Compostable jiffy pots work great because they can be planted directly into the veggie patch once the cutting matures. A mini-greenhouse can help to maintain warmth and moisture. Water the soil thoroughly after sticking your new plant.
7. Place cuttings on a warm windowsill or in a mini-greenhouse and water daily. If stems begin to form flowers or leaves die off, don’t get concerned – these forms of plant stress are ways the plants cope with the transplant. Just remove the flowers or dead leaves to help it refocus on the root growth.
8. It will take anywhere from a few weeks to more than a couple of months to develop meaningful roots. When cuttings begin to form new leaves, or visually chase the sun, the plant is nearing readiness. Once roots begin to hold soil – if you pull at the stem and the soil bulges with it – the plant is ready for transplant.
This is an edited extract from Grow. Food. Anywhere. by Mat Pember & Dillon Seitchik-Reardon published by Hardie Grant Books RRP $45 and is available in stores nationally. Image credit: John Laurie