The Acacia is one of the largest species of trees in the world. There are over 800 different types of acacia growing in warm, tropical, and desert-like regions of both hemispheres. Acacia is a fast growing, but short-lived tree. The average life span is only 20 to 30 years and it can grow to a height of 40 feet. The yellow or white flowers provide a spectacular show and many are highly scented. The hardiness of the acacia depends on the variety grown. The zones range from 8 through 29. Although this tree is not easy to propagate from seed, it is not impossible either.
If you have acacia seeds to plant, don’t just throw them into some potting soil and think that nature will take care of the rest. Chances are you won’t be very successful. In order for the seeds to germinate, special treatment is required.
Harvest the Seedpods
The acacia seedpods are approximately 3 inches long, and each pod contains five to six seeds. Harvest the seedpods when they are have turned brown and dry. When you shade the seedpods, you can hear the seeds rattling inside.
Prepare the Seeds for Planting
Remove the small black seeds inside by breaking open the seedpods. Separate the seeds from foreign matter and place the seeds in a small bowl. It is always best to plant them right away, but if you cannot, transfer the seeds into a vial, envelop or other container. Store the seeds in a cool location until you are ready to plant.
Before you plant the acacia seeds, scarify them by rubbing one side of the seed with fine sandpaper. You’ll only want to rub the seed coat just enough to scratch the surface so the water has an easier time penetrating to waken the inside embryo. Do not rub the seed coat so much that you go through the hull as this will kill the seed.
Fill a teakettle with water and bring it to a boil. Place the scarified seeds in a bowl or cup. Pour the boiling water over the seeds covering them completely. Leave the seeds soaking overnight.
Preparing the Pots
The next morning, fill several 2-inch pots with moistened seed starting soil. A good way to moisten the soil is to cover the worktable with an old plastic tablecloth or tarp. Dump some seed starting soil on top. Using a sprinkle can, wet the soil with water. Only add small amounts of water at a time. You want the soil lightly moistened, not soggy wet.
Fill the pots with the moistened soil, planning on one seed for each pot. If you’d rather, you can sow three seeds in each 6-inch pot. Lightly firm the soil in the pots with your fingers. Don’t press too hard or the soil will compact and become hard.
Planting the Seeds
Toss out any seeds that are floating on top of the water because they are not viable. Place one seed in the center of each 2-inch pot. If you are planting in the 6-inch pots, space the seeds evenly apart. Push the seeds so the seed coat is in contact with the soil. The seeds need partial exposure to light in order to germinate so do not cover except very lightly with vermiculite.
Warm Location
Place the pots in a warm location that receives 8 to 10 hours of sunlight per day. In the wintertime, this is almost impossible with the shorter days, so you will need to place the pots under a grow light.
Monitor the soil to make sure it stays moist. If you planted seeds in the 6-inch pots, only the top 1/2 inch of soil needs to stay lightly moist.
It takes two weeks or longer for the seeds to germinate, so be patient. When the seeds sprout, continue to grow them in the bright location or under grow lights.
Transplanting the Seedlings
Transplant the seedlings into 6-inch pots when they have their second set of true leaves. If you are growing them in 6-inch pots, carefully remove two of the smaller trees. You don’t need to throw them away. You can transplant them into their own 6-inch pot.
When the acacia outgrow the 6-inch pots, transplant them again into 3-gallon containers. Fill the pots with a mixture that is 75% garden soil and 25% sand. Continue to grow the acacia in the pots until the spring.
Transplant them one last time into their permanent location in the spring.
Sources:
20-20 Site: Acacia Trees
“American Horticultural Society A to Z Encyclopedia of Garden Plants”; Christopher Brickell; 2004
