How to grow new plants from old – with a little help from Mitre 10
Successful propagation essentially depends on knowing the best type of wood to take, having a good root-inducing propagating mixture and providing the right environment while the cuttings strike
Tools for the job
- Propagating knife
- Sharpening stone
- Watering can or bottle sprayer
- Hormone cutting powder or liquid
- Coarse sand
- Peat moss, vermiculite or Perlite
- Cutting or propagating mix
- Detergent or disinfectant
- Small stakes
- Plastic pots, trays, punnets, wooden or styrene boxes
- Clear plastic or glass
Step 1: Collect and prepare your cuttings
Decide which type of cutting you wish to be prepared then collect the plant material early in the morning when it is cool. Spray with a little water to keep them alive until you can prepare the cuttings. A cutting is simply a piece of a plant such as a leaf, a piece of stem or root which, when planted in the right environment, produces another plant. The main types of cuttings that you can do at home are stem cuttings and depending on the time of year and the conditions in which you wish to grow them you should use one of the following: Softwood or Tip cuttings are taken early in spring through to summer when the plants are in active growth. The soft fleshy growth of about 50-75mm long is taken from the tip of the stem cutting just below a bud. The leaves are removed from the bottom 1/2 of the cutting. These cuttings need a lot of tender loving care, such as small propagation box with a regular misting with water. Semi-hardwood cuttings are prepared from slightly mature wood, usually around late spring to early autumn. Cuttings look much the same as tip cuttings except the very soft tip is removed. The leaves are removed from the bottom 1/2 of the cutting leaving 1-3 nodes with leaves. This type of cutting seems to be the most successful for the average home gardener. Hardwood cuttings are usually prepared from the mature wood in late autumn and winter. The mature wood is usually cut into lengths varying from 100mm – 250mm depending on the species. There should be a slight sloping cut at the top just above a bud and a flat cut at the bottom just below a bud. The base is often wounded to help roots to grow. These cuttings are very easy to grow for most gardeners.
Step 2: Propagating mixtures
Your growing mixture should be free of weeds and disease, sterile if possible. The mix needs to be porous and drain freely while still holding moisture. Coarse river sand is useful, but it tends to dry out too quickly. A better mix is one you make up using: 3 parts coarse river sand 1 part peat moss.
Another very good light propagation medium is to mix:
- 2 parts Perlite
- 2 parts coarse river sand
- 1 part peat moss
Various brands of propagating mix are also on the market and available through Mitre 10 stores.
Step 3: Cutting containers
The best and easiest to obtain are plastic pots, trays or punnets. Cut down wooden or polystyrene foam fruit and vegetable boxes are also suitable. All are easy to clean, so make sure any container used is washed thoroughly before planting with hot water and detergent or dip in a solution of household bleach or another disinfectant. As with most plants, good drainage is essential. Any containers used should have drainage holes cut or drilled in the bottom.
Step 4: Planting
Cuttings should be planted as soon as possible after taking and dipping the cleanly cut base into a hormone cutting powder or liquid. There are a number of these products available from your Mitre 10 Garden Department and they help cuttings make roots quickly. Place a small quantity of powder or liquid rooting hormone into an old bottle cap and dip the bottom 12-20mm of the cutting into it. Once you have treated all your cuttings discard the remaining powder so as not to contaminate the unused hormone. Fill your container with slightly damp propagating mixture to within about 15mm of the top. Plant your cuttings in the container to about one-third of their depth into a hole made with a pointed stick or old knitting needle. Space them so that they are not crowded, otherwise rotting will occur. Firm by pressing the mix around them. Water in well and keep the container moist, but not wet. Avoid moving the cuttings too early, and then transfer to individual 7-10cm pots until advanced enough to plant in your garden.
Step 5: Growing climate
The success in striking your cuttings depends on the climate you provide for them. High humidity is needed to prevent the cuttings from losing moisture Nurserymen call this a microclimate and provide it in glasshouses with misting systems. All that’s far too elaborate for the average home gardener, but you can easily improvise. Inverting a glass jar or a plastic drink bottle with the neck cut off is one way. Using a clear plastic bag supported by stakes or wire is another. Any of these simple home methods create the humid atmosphere needed by preventing moisture from escaping. A good size propagation box can be made from heavy-duty clear plastic stretched over a frame of 75mm x 50mm treated pine or hardwood. A box like this can protect your cuttings as well as provide the ideal conditions for those difficult vegetable seeds. Light waterings with a small mist sprayer is recommended to create humidity and to keep the propagating mixture moist and cuttings fresh. Good ventilation is also a must in creating the right environment. When the days are warm lift the cover a little to allow the air in, but not so much as to dry out the cuttings. The top of your propagation box should be rolled up a little. Provide shade from direct sunlight as well, or too much heat will build up in the enclosed area causing the cuttings to stress and wilt. Most cuttings strike best at a temperature between 20-25 degrees celsius, so shade them from the sun with either newspaper, hessian or shade cloth for a week or two. Then harden them up to direct sunlight as root growth begins.