Before you plant your eucalyptus tree seed, take a few minutes to consider your yard’s suitability. Most varieties of eucalyptus need full sun, fertile well-drained soil and mild winters. And most of all, eucalyptus trees need space. They can reach over 300 feet in height and may grow as much as 10 feet annually. If your yard can support this giant beauty, you'll find that eucalyptus trees are easy to germinate from seed and transplant.
Take a sample of soil from the planting area and take it to your local county extension office for testing. The resulting test will reveal the nutrient and pH level of your soil and prescribe any necessary soil amendments.
Dig up a 25-square-foot, 2-foot-deep area of soil over the planting site with a shovel. Then till the soil to loosen it and break up any clumps. Add any necessary soil amendments as prescribed by your soil report, then till the soil again. Finally, smooth the planting area over with a rake.
Clean the interior of a 6- to 8-inch pot with drainage holes with bleach and water. Then fill it with a seed-starting soil up to 1 inch from the rim of the pot. Then tap the pot on the table a few times to settle its soil and press the surface lightly with your hand to level the soil.
Sprinkle a pinch of eucalyptus seeds over the center of the pot. Then cover them with a thin coating of coarse sand (no more than 1/4 inch) and press it down.
Gently water the soil until it is moist. Continue to keep the soil moist until the eucalyptus seeds are ready to be transplanted outside.
Keep the pot in indirect sunlight until the seed germinates in roughly one month. Once the seed sprouts, set the seedling in a sunny windowsill.
Transplant the eucalyptus seedling in the planting site in mid-summer once it has reached 8 to 9 inches in height. Plant the seedling roughly 1 inch deeper than it grew in the pot. Do not allow the seedling to stay in the pot any longer than this. Eucalyptus grows quickly and if it becomes root bound in its pot, it will take a long time to establish itself. And its roots will not expand enough to support the tree against strong wind when it becomes an adult.
Water the transplanted seedling so that the soil is moist to the depth of its roots. Continue to keep the soil moist until the seedling establishes itself and produces new growth.