These principles are designed to help you get started with propagating native plants at home.
Seed raising mix
Considerations: porosity, length of time the seeds will be in tray/pot, nutrients and space. Options:
- Cocopeat and perlite, mix 1 to 4, maximum drainage, short timeframe, limited space, no nutrients
- Debco seed raising mix, holds water, keep seedlings in longer, low phosphorous fertiliser
- Seed raising mix or soil plus sand, more drainage than above, keep seedlings in longer, low phosphorous fertiliser
- Seaweed solution is also recommended by VINC and SKINC to help with root growth
Seed trays or pots
Choose seed trays and pots that drain all of the way around the container, and have larger, possibly round drainage holes so the roots aren’t shredded when potting, and drain at the base so roots don’t sit in water at the bottom of a tray or pot and rot.
- Wet the soil before planting and lightly moisten with sprayed water after planting.
- Plant seeds to a depth that is around the diameter of the seed. Large seeds germinate in the dark and need to be deeper in the soil, small seeds generally require daylight and need shallow planting, plant tiny seeds on the surface with a light covering.
- Relative humidity needs to be kept about 70%, with the use of plastic covers. Too humid and you get dampening off – fungus. If the air is too dry the seedlings wilt.
- Temps in the range 18 to 25 C.
- Water needs to be mist, keeping the soil damp, not wet nor dry.
- Melbourne is the windy city. Drafts mean fans are not necessary, but watch those drying winds.
- Check online for specific seeds and the best time to plant.
- Germination can take from 1 week to 3 months.
- Old mix, and even new stuff left in the shop too long needs added fertilizer. Choose low phosphorous, high nitrogen ‘grow’ fertiliser once the seedling appears.
- Plants ready a further 1 to 3 months later, and can be held for about 6 months in the pot.
- After producing trays of seedlings, they need to be transplanted and potted up, under high humidity for 48 hours.
If you want to get even more serious, you can try heat mats, fogging equipment and supplementary lights.
Wash pots and change the seed raising mix if you’re concerned about weeds, provenance of plants, mixing plants if old seeds grow later and pathogens.
- Choose young actively growing stems.
- Cuttings are best at around 10 – 15cm, with a firm stem. You can cut the top off of the cutting to have a good cutting at about the right length and strength. Cut just above the node a 45 degree angle to stop water from settling on top of the plant and causing rot.
- Cut leaves away from the base so there is air circulation around the base and the leaves don’t get wet, droop and touch the soil when they are likely to rot. Cut off flowers.
- Cut at a 45 degree angle, just under the node at the base, put in rooting mixture, and then pot. Make sure cuts are clean to limit damage to the cutting.
- Cuttings need to be kept immediately wet at the base.
- Cuttings require a cutting soil mix, and similar conditions as for seeds.
- Keep wet for 3 days, but don’t water the leaves – no wilting, and then dry down to just damp.
- Keep cuttings in shade for 1 week and gradually increase light intensity/heat/dry air exposure.
- Cuttings produce clones, which doesn’t support genetic diversity, so it’s a risk if a disease spreads as all plants will be affected.
- Pay attention to anything that will damage your plants – Keep them off the ground to avoid slugs and snails, consider rats, black birds and possums
- In the industry, plants raised in polys are hardened off by exposing to full outdoors for 1 week so they are more successful at transplant.
- Use clean, sterilised tools, such as secateurs washed in alcohol steriliser to prevent spreading diseases
- Use secateurs that have two sharp edges for cutting, rather than on blunt edge and one blade.
If you enjoy plants, paying attention to them is hopefully enjoyable. You might want to record when you plant seeds and how and their growth to learn from your experiences. Check on them to make sure they’re getting enough sun and water.