A general rule which is useful for most native tree species is: germinate the seed about three to four months ahead of the intended planting-out-date and when daily temperatures are sufficiently warm.

Although the ideal temperature for germination varies with the species, many species will germinate when daily temperature rises above 20 C. The seed of a number of cool climate species will sprout when daily temperatures reach 15, and some tropical species prefer 25 to 35. If you decide to sow when days are cooler than this, you may need to use some form of heating.

Some seed must be sown as soon as it is collected. Although seed of many native tree species can be air-dried in a warm room and stored successfully for years, the seed of other species will not tolerate drying. Storage of these is impossible or at best only partly successful; the seed of many fleshy-fruited rainforest species such as lilli pilli (Syzygium spp.) is in this class.

Hygiene before sowing
Losing a crop of tiny plants to disease can be a big disappointment, so start off with a few simple but effective hygiene measures. Firstly, aim to avoid spreading plant diseases in soil attached to trowels, the bench top, gardening gloves and re-used germination trays so before preparing sowing mixture or sowing a batch of seeds, wash all soil from the equipment you plan to use.

When you finish handling one lot of soil or sowing mix, before handling another lot, wash all soil and
mix off the equipment and then wash your hands with soap.
These precautions will prevent many outbreaks of disease. But if disease is common in your district or has previously broken out amongst your plants, or if you plan to raise large numbers of seedlings, strengthen your precautions by also using a disinfectant.

Either make up a disinfectant from household laundry bleach (20 ml per litre of water) the mixture will keep for a week and can be re-used during that time or buy a disinfectant from a chemist.

After washing your hands dip them in the disinfectant. And after washing the soil and sowing mix off the tools and other equipment, soak them in the disinfectant for 5 to 10 minutes. Also wash the bench top down with disinfectant

Germination trays
Seed is often germinated in trays of sowing mix, and the seedlings are later transplanted into separate individual containers. Plastic punnets or larger trays with fine holes in the base are suitable for germination trays and can be bought at garden shops and nurseries. Plastic containers such as icecream or margarine tubs are also suitable but some fine holes must be made underneath to allow water to drain away freely.

If a germination tray has been used previously, wash it well in water and household detergent, and then soak it in the disinfectant for 5 to 10 minutes. Trays about 15 cm long, 10 cm wide and 5 cm deep are convenient for small seed such as those of many eucalypts such a tray is suitable to produce about 50 to 70 seedlings. Bigger trays can be used for larger numbers. Large seed with a high strike rate such as many of the wattles (Acacia spp.) is often sown straight into their individual containers.