Filling germination trays
Pour sowing mix into the tray until it is almost full and then bump it gently on the bench to remove any air pockets. Trays are easier to fill if the mix is dry. Then level the surface with a flat board or a knife blade and water the tray either from above or below. To water from above, apply a fine spray with a small hand sprayer.

Alternatively, to water from below (bottom-watering), stand the tray in water about half as deep as the mix - the water will soak upwards and the mix surface will change colour slightly when the water reaches it. Then remove the tray from the water.

The mix will settle slightly when watered and, before sowing, the mix surface can be below the tray's rim by at least twice the thickness of the seeds. This distance leaves room for the seeds and for a covering layer as thick as the seeds.

Sowing
Sprinkle the seeds evenly over the surface, but avoid sowing them too densely as this may produce weak spindly seedlings and also encourage fungal disease. Allow for the possibility of substantial losses from pathogens. As a rough rule of thumb, only about 25 to 50 per cent of eucalypt seeds sown will produce vigorous seedlings suitable for planting out.

Very fine seeds can be sown more evenly from a 'salt shaker' seeder. Take a small screw-topped jar and punch scattered holes up to 2 mm in diameter in the lid. Place the seed
in the jar and add an amount of fine white sand equal to about three times the seed volume. Mix well, and sprinkle over the surface.

After the seed is sown, take some mix or fine sand and cover the seed to a depth equal to their width or thickness - whichever is least. This covering keeps the seed more moist and warm. Fine seed such as that of paperbarks (Melaleuca spp.) and many eucalypts need a very light covering - just thick enough to hide them from view.

With large seed, a mulch of 3 mm granite grit may be added on top to reduce drying out and avoid any formation of a surface crust on the mix. The grit also makes watering with a spray easier. Water each tray then immediately label it with a plastic marker or strip of masking tape on which is written the species, the provenance (the geographic area the seed was collected from) and the date of sowing.

Wetland (bog) method
Some species such as bottlebrushes (Callistemon spp.) and tea-trees (Leptospermum spp.) produce seed which is so fine it is almost like dust. The seed often germinates readily but the tiny seedlings are easily damaged by overhead watering or rain, or may be killed if the sowing mix dries. The wetland or bog method avoids these problems in the wild, some of these species grow on poorly-drained sites.

Prepare a germination tray and, as the risk of disease is higher with this method, pay special attention to hygiene. Sow the seeds on top of the mix and do not cover them with mix.

Stand the tray in an empty plastic icecream tub or similar container and add water until the level reaches about halfway up the tray. The water will soak up to the mix surface. Leave the tray standing in the water in the container, and then fit an inflated plastic bag over the container to keep moisture in. Top up the water in the container every day or so to make sure the sowing mix is always moist.

About a month after germination, remove the tray from the water in the container even though the seedlings are still very small. If this is not done, the risk of fungal disease due to excessive moisture is high. After that, water the tray from below as described above in the section Filling germination trays.

If disease breaks out, treat it immediately using the methods described below in this pamphlet. If a species proves disease-prone, add more coarse sand or fine gravel to the sowing mix to make it more open, and make some cuts in the plastic bag to allow some air movement. Standing the container in the dappled sunlight beneath a shrub, or under a shadecloth cover placed in sunlight can also help.