At long last! After three drawn-out months of scrambling through undergrowth and dangling from tree-tops (seed collection), of gastrointestinal anguish and carpal-tunnel syndrome (seed processing), and of complete and utter phonetic confusion (having to learn Latin just to understand the identification books), the moment of glory has arrived – chucking that damn seed at a pile of dirt and letting it grow!
Well… if only it were that easy. Perhaps it is; nature has been using that method quite successfully since the dawn of plants. The catch for us is, we are now wanting to chuck our specially chosen seed at a bit of dirt and hope that it grows in preference to whatever nature put there before we had this crazy idea.
Enter the nursery industry.
Try and grow your preferred plant in any old patch of dirt? You’ll probably get a harvest of ‘weed’ seedlings before you find ‘your’ plant. Enter highly-refined, highly-transported potting media. Nearly-sterile to the point of needing inoculation for the healthy growth of some plants that rely on symbiotic soil microbes (many Nitrogen-fixing plants for example), but at least you can be confident that the green shoots that emerge are from ‘your’ seeds.
Try and grow your seed in any patch of dirt, in any old location? Even if you escaped the weeds, how well do you know your soil, what is its composition? Enter more highly-refined, high-energy-consumption additives for your potting media, to adjust porosity and water-holding capacity or to provide a regulated supply of certain key nutrients. Then how do you keep your seeds at just the right moisture content for ideal germination without drying out or drowning? Or stop them from being eaten? Enter the magnificence of the petrochemical industry, with its poly-pipe, its shadecloth, its propagation tunnels and misthouses, its engineered sprinklers… all still relying on the mining and manufacturing sectors to provide electricity, metals and semiconductors to the fancy irrigation controllers, solenoids and pumps…
All seems rather daunting, and not-very-landcaring-at-all, yes? Well, ‘daunting’ is probably why a lot of people in these modern times have supported the boom of industrial plant propagation – we’re too busy or under-resourced to tackle nature head-on and get the quick-fix we desire. So we trot off to our nearest plant supplier and take something green home in a shell of petrochemical plastic, hiding our ignorance or denial behind a fresh bit of vegetation in our front hedge or back-paddock gully.
But it doesn’t all have to be that hard.
Nature has solutions for us; the first step in finding them is un-learning what I call the ‘control paradigm’ of our culture and times. That’s a digression for another story though, so for now, I’ll skip straight to what some of those solutions are.
- Leaf litter
Compost is nature’s all-purpose germination, potting and fertilising media. Done well, it can make backyard propagation enjoyable and easy. Done very well, it can even be too good for a lot of native plants. Almost like death by chocolate. Or wine.
Leaf litter (usually the older, decomposing layers) is nature’s inoculant, bringing the ‘life’ into any soil. It is where almost all plants germinate, before their roots venture deeper into the ground. It can also help moderate the density and nutrient-richness of compost in a potting media.
Sunlight is a wonderful source of warmth and sterilising radiation, which when applied to the above items can get you just the right results for a clean germinating media.
Gravity (plus a sieve) is a great tool for helping sort out your ingredients (as well as your seeds) to get the ideal size of media to suit your chosen seed.
Erosion is nature’s sieve – with rain and gravity, it can create a palette of shapes, sizes and textures for you to play with. Be it washed leaf-litter, sands or silts, it can provide you with additives for your media or help in removing some materials from your mix.
Rain of course needs no explanation. It does however need some patience on our part. When coupled with gravity, it is what makes your watering-can work. Or your leaky weir. Or, if you just can’t resist a good bit of poly pipe and a sprinkler from a header dam (or your local urban water-tower), then you can thank gravity again.
Vegetation is nature’s weed-fence, shade house and humidifier all-in-one. Just pick the right vegetation: under a mango tree might be great for seedlings… except in January as the fruits plummet earthwards.
None of that is new knowledge of course. It is the building blocks of the industrial-scaled alternatives mentioned earlier. Sometimes though, us humans would do well to be reminded that behind all our supposed intelligence and inventiveness, we exist as mortal, biological beings dependent upon a world of other biological beings.
Now how does all this come back to the topic of seed propagation? Well, it is about renewing your powers of observation and acceptance. Observing how nature grows seeds. Accepting that the easiest way to grow our own seed is to follow nature’s lead.
If propagating plants from seed is new to you, then by all means start with the tried-and-tested basics, even if that includes bagged seed-raising mix, fertilisers, containers and packaged garden-variety seed from a local retailer. Learn what does work and why it works, so you can then understand what ‘rules’ you can later bend.
As you venture into propagating native seeds, hone those observation skills. When you collected the seed, what time of year was it? What sort of soil was the parent plant growing in? Were there any seedlings nearby and if so, what sort of conditions appeared to favour their germination and growth? How did you go with previous propagating trials?
Such questions, study and observations of my own have given me a few ‘baselines’ to work from in propagation, such as:
- Eucalyptus are reasonably fine seed; they germinate quite well sown on the surface of soil or with a very light covering. It can be hard to see the difference between viable seed and ‘frass’ so viability may not be known until after a batch is sown and germinates. Species from the drier forest types can germinate better with a warm soak before sowing. Winter is often woeful for germination.
- Acacia do best with a warm-hot soak before sowing. Given most Acacias are a dry-forest type, they won’t fare so well in heavy/wet propagation media.
- Casuarina don’t need treatment; the dry-forest species may germinate better after a warm soak but they have an intriguing characteristic of clumping together like a wet cotton-ball after they get wet, so it isn’t worth the hassle of soaking them.
- Melaleuca are typically a wetland plant, at least for establishment, so keep the germination media constantly moist. Some species may take several weeks to germinate. Very fine seed – sprinkle on surface or with very light covering.
- Small fruity seeds (Streblus, Aphananthe, Guioa, etc) don’t have a great shelf-life, so process the fruits and sow the seeds promptly. Soaking can help pick out the good seed (usually it sinks) from the bad (usually it floats) but it is rare to get a big enough collection of seed to bother with this step.
…And so forth. Again, there are plenty of resources out there on species-specific propagation techniques. Far more than would fit in one newsletter article.
The last aspect I will leave you with, is how to sow the seed. Do you use community trays or boxes where you sprinkle seed across the full area of the container, then pot the seedlings up individually? Do you sow directly into pots with just one seed or a pinch of seeds per pot? Do you allocate a corner of your garden to bury those species that sometimes germinate over several years? Do you pre-treat the seed (e.g. hot soak), roll it up in a ball of soil/clay and throw it at a bare riverbank or road cutting? Do you sow it directly in the field where it is to live, after ripping and spraying strips? Each of these options has its pros and cons. Community trays are a good way to get a lot of seedlings from a small germination space, but then the seedlings have their roots disturbed by potting-on and shallow trays can dry out much easier than pots. Sowing in pots lets roots develop naturally but only works well for seed with a known viability. Garden-bed sites can be a ‘set-and-forget’ option but might get oversown with several species and seedlots, testing your identification skills in years to come. Distributing seed into the field may be quicker than planting but typically requires far more seed to get the desired final numbers of plants surviving. Each of these aspects will also vary for your individual circumstances and local conditions. In our high-rainfall coastal areas, the growth rates of pasture grasses and legumes is one deterrent to direct seeding in the field, for example. But direct-seeding a steep eroding creek-bank at the tail-end of summer/autumn rains might cause less disturbance than planting tubestock, even if the result takes more seeds at the start and a few more years to see the visual difference. On the other hand, certain species that would have historically grown in a particular location may only be reintroduced in our lifetime by planting tubestock or even advanced potted plants. There are, perhaps, as many ways to propagate a native plant as there are feral cats to skin! But don’t let that stop you trying native plant propagation (or feral cat reduction either, for that matter).
The Australian Native Plants Society has more information on the practical steps involved in seed germination. To go to their website, please click here.