By Anne Davies
Learning to propagate is a satisfying way to keep your garden flourishing without spending a lot of money.
Propagating is the process of growing new plants from old; there are many ways to propagate plants, including cuttings and seeds. Once these propagated plants have developed roots, they usually need to be potted into larger containers before planting in the garden. This process is known as 'potting up' and the key to success is using quality potting mix.
One way to ensure you buy decent potting mix is to check for the Australian Standard 'ticks'. The black tick means the mix meets all the recommended criteria but has no fertiliser.
The red tick includes fertiliser to last up to three months; however, due to transport and storage, this fertiliser may have broken down by the time you purchase it. A good option is to buy black tick Australian fertiliser and add your own controlled-release fertiliser.
Potting mix needs to have the following properties (1) good drainage so there is air available for the root system to process energy and grow well; (2) the ability to hold moisture, which is essential for the plant's growing processes; (3) the right amount of nutrients and also the correct pH (around 6.5 to neutral), ensuring the plant can take up the nutrients for healthy growth; and (4) the correct amount of support to stop the plant from falling over.
Potting mix is made from different ingredients mixed in ratios to suit the plants being grown. Commonly-used ingredients are sand, peat composted pine bark, vermiculite and perlite.
Never use soil for potting mix because it may contain pests and disease and can become waterlogged in containers. Just as soil is no good for potting up, the same applies to using potting mix in the garden. Potting mix is an expensive and inefficient way of trying to improve soil; use compost to enrich your soil.
Potting mix can possibly cause harm to your health, so it is important to take some precautions when using it. Ensure the mix is damp and not dusty, use a disposable mask, and wear eye protection and gloves.
Always wash your hands when you finish potting up. Health risks associated with potting mix include legionnaire's disease, infection of open wounds, tetanus and respiratory ailments.
It's important to use the correct container – it must have good drainage holes and be the right size. You should never pot up into a much bigger container because the new roots will be sitting in cold, damp soil.
For instance, if you propagate your plants in trays you should pot up into tube stock; if they are propagated in tube stock, then you should pot up into 140 mm pots.
You must also consider the light requirements of your newly-potted plants. Most plants are propagated out of direct sunlight so when they are potted up they need to be gradually introduced to direct sunlight. This process is known as 'hardening off' plants.
Follow these tips and you'll have plenty of plants for your garden or to give away to friends-and you'll have pots of fun doing it. •
Courtesy Salvation Army Warcry magazine. Anne Davies is nursery supervisor and trainer at the Salvos' Tom Quinn Community Centre, Bundaberg (Qld)