Growing Plants from Seed

A lot of plants we grow in gardens can be grown easily from seed. Sometimes it's the only way to grow the plant, such as some heirloom varieties offered by seed companies like Diggers (click here to see our information sheet on heirloom varieties). And some plants can't be propagated any other way.

Seeds themselves vary considerably too, as can be seen in the photograph here. Clockwise from top is Hairy Wattle (Acacia vestita) seed pods and seeds, native Red Grass (Bothriochloa macra), lettuce, broad beans, tomato and parsley.

Some seeds virtually sprout in a few hours. Sturt's Desert Pea (Swainsona Formosa) for example, germinates very readily after soaking in warm water. Other plant seeds take weeks and even months, sometimes because they require a special period of treatment, such as a cold winter, before germination.

Some seeds germinate on the surface and some won't germinate until well-covered. (A general rule of thumb here is that the finer the seed, the closer to the surface it is sown.)

Some require damage to their outer coat prior to sowing, to break down the natural inhibitors to germination. Wattle seed, for example, needs to be soaked in boiling-hot water to soften its seed coat.

Some Australian native plant seeds require treatment with smoke - to mimic bushfire. Smoke water is now sold in nurseries, especially native plant nurseries. The seeds are soaked in this water prior to sowing. The smoke breaks down the chemical inhibitor in the seed coat.

On packets of seeds, there should be instructions on how to sow that particular seed. There is certainly plenty of information on the web and in books on sowing a wide variety of vegetables, herbs, annuals and perennial seeds.

Many ornamental plant seeds require special treatment before sowing, so read up on it first and the likelihood of success will be much greater.

It's not always legal to collect seed from wild plants, especially rare and endangered plants, so check with your relevant environment authority first.

Pests

Many animals eat seeds, including birds and ants, and other animals lie in wait for the emerging green growth, such as snails and slugs (see our information page on snail and slug control). If growing in seed trays etc, control of animals is much easier, but if sowing directly into the ground, their protection becomes more of a challenge. Pillaging birds will appear shortly after sowing and promptly steal the lot.

In their book Ecology for Gardeners (Timber Press ), authors Steven Carroll and Steven Salt suggest a number of strategies for the environmental gardener, such as: laying mesh down over the area, standing guard, posting a watchdog, or planting substantial extra seed!

A very useful tip is not to carelessly plant seeds so that some are left unburied on the soil surface. Unburied seeds attract birds and 'will serve as an invitation to search for other buried seed nearby'!

Diseases

Seeds and especially emerging seedlings are susceptible to fungal diseases. Often this can be prevented by not overwatering.

Most seeds need to be kept damp but not wet. Damping off (Fusarium sp) disease is a fungal disease caused primarily by over watering. A sure sign of the disease is when seedlings start falling over, one after the other.

If this happens it's wise to start again, thoroughly cleaning all equipment and composting the infected seedling raising mix.

Seedlings can be drenched with a weak copper fungicide solution too.

The Australian National Botanic Gardens provides useful advice on growing Australian plants from seed at www.anbg.gov.au/PROPGATE/plant01.htm

Information sources:

Hartmann, H.T., Kester, D.E., Davies, F.T., Plant Propagation: Principles and Practices, publishers Prentice-Hall International.
Elliot, W.R., & Jones, D., Encyclopaedia of Australian Plants, Lothian Publishers.

For more information: www.greenplanet.net.au

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