What you will need for propagating clones:
- Grow media for the clone:
A rockwool cube - grodan rockwool is what we use for water based hydroponic systems or aquaponics
- A jiffy pellet (peat moss) for a coco or soil system
- pH down and a pH test indicator to check your pH. pH down is an acid that is beneficial to plants.
- A propagator - tray and lid that helps to control the seed's environment
- Root hormone gel such as GT CLONEX or EZI-ROOT.
- CFL Propagation Lights such as T5 CFL Purple propagation lights or other CFL grow lights - very soft lighting is required.
For best results, also invest in the following (in order of importance):
- A heat mat - a mat that has an adjustable thermostat or stays at an even 25°C. Some people sit their tray on the top of their hot water heater - warmth is essential in winter
- Rooting tonic - specialised rooting solution to speed up growth and promote thicker roots. Comparing a rooting tonic to just using water is like chalk and cheese.
- Thermometer / Hygrometer to check temperature and humidity
Steps to propagate with rockwool
- Prepare the propagation nutrient water using either: Bloom Roots, Rhizotonic, or Roots Excelurator. Using pH Down, adjust the pH of the propagation nutrient water to a pH of 5.5.
- Soak rockwool cubes in the nutrient water for a minute to make sure the water is dispersed throughout.
- Take the rockwool cube up out of the water and give it a very slight squeeze so it is damp but not water logged. The remaining solution can be used for watering later.
- Using a sharp sterile scalpel (secateurs for hardwood cuttings), create a cutting from the most vigorous growth (older more mature parts of the plant for hardwood cuttings)
- Stem must have 3-5 pairs of leaves and be 10-15cm in length.
- Remove the lowest pair of leaves.
- Make a clean diagonal cut just below the lowest leaf node, immediately dip the cutting into the propagation gel and insert cutting into the rockwool to a depth of about 1.5cm.
- Place the cutting and rockwool in the propagation box. Ensure the excess water can drain from the rockwool so that it is not sitting in the nutrient water.
- During winter, use the heat mat under the propagation unit to keep the rockwool between 22 and 25°C and enough humidity to create condensation.
- Connect the light to a timer to provide between 18-24 hours of light per day.
- Check the rockwool cube after a couple days, it should still be moist. If the rockwool appears dry and lighter in weight, propagation water can be sprayed onto the cube to increase moisture. It is important to note that the rockwool should be kept moist but must not be waterlogged. Too much water can create low oxygen conditions and can cause the stem to rot.
- When roots emerge from the rockwool cube, add nutrient solution of no higher than 1.0 EC and a pH of 5.5 to give the roots additional nutrient and water.
- Plant the cutting out!
The most common errors we see when propagating clones
- Keeping rockwool cube too wet and causing the cutting to rot – use a lattice tray or a tray with plenty of drainage
- Not providing warmth - use a heat mat in winter
- Bruising the cutting.
For more tips on growing and propagation with rockwool check out the book Gardening Indoors with Rockwool.