How to Grow Key Lime Trees From Seed
Sometimes called Mexican lime, key lime (Citrus aurantiifolia) is a compact species of tropical tree grown for its tart, edible fruit and aromatic foliage. It grows in U.S. Department of Agriculture plant hardiness zones 9 to 11, where it will reach a height of 20 feet with a dense, rounded canopy of evergreen leaves. Unlike most fruit trees, key limes propagate reliably from fresh seeds and the resulting trees will begin producing fruit in three to six years. The seeds are susceptible to rot and must be grown under barely moist conditions to successfully germinate.
Gather key lime seeds as soon as the fruit ripens to a solid, light green color. Pick two or three healthy, unblemished fruits directly from the tree rather than gathering them from the ground. Avoid fruit with bird pecks or other signs of damage.
Slice the fruit in two with a knife. Squeeze out the pulp into a bowl. Pick out the small, pale brown seeds and place them in a shallow bowl filled with clean water. Gently clean the seeds, then rinse them.
Spread the key lime seeds between two sheets of paper towel. Leave them to dry them for one to two days. Rub the seeds gently to dislodge any dried flesh or pulp still clinging to the hull.
Sow the key lime seeds in individual 4-inch pots filled with a sterile, fast-draining growing mix made up of equal parts seed compost, perlite and horticultural sand. Sow them at a depth of 1/2 inch.
Place the pots inside a lightly shaded greenhouse or indoors near a south-facing window. Arrange the pots on a germination mat that is set to 80 degrees Fahrenheit. Cover the pots with a clear plastic propagation dome or a sheet of plastic wrap.
Maintain constant, light moisture in the top 1 inch of growing mix. Water with a spray bottle to prevent the growing mix from becoming saturated. Always let the top 1/4 inch dry out between waterings.
Lift the propagation dome for 20 to 30 minutes every day and whenever condensation forms on the inside. This allows trapped moisture to evaporate. Poke holes in the plastic wrap, if you are using it instead of a propagation dome. Watch for germination in two to six weeks after sowing.
Keep the pots warm with the germination mat for one month after germination. Lift the propagation dome once the seedlings unfurl their first leaves.
Grow the key lime seedlings under warm, sheltered conditions until mid-spring, or once daytime temperatures reach 70 F and nighttime temperatures stay reliably above 55 F.
Transplant the key lime seedlings into larger nursery containers, filled with citrus-formula potting soil, once they are 2 inches tall. Grow them outdoors with limited afternoon sun until late summer.
Acclimate the key limes to direct sun for two weeks in late summer. Transplant them into a permanent bed or large container in fall, when the weather is slightly cool and moist.
- California Polytechnic State University Urban Forest Ecosystems Institute: Key Lime
- Purdue University Center for New Crops and Plants Products: Citrus Aurantifolia
- USDA Forest Service International Institute of Tropical Forestry: Citrus Aurantifolia
- Trade Winds Fruits: Key Lime
Samantha McMullen began writing professionally in 2001. Her nearly 20 years of experience in horticulture informs her work, which has appeared in publications such as Mother Earth News.
How to Grow Key Lime Trees From Seed. Sometimes called Mexican lime, key lime (Citrus aurantiifolia) is a compact species of tropical tree grown for its tart, edible fruit and aromatic foliage. It grows in U.S. Department of Agriculture plant hardiness zones 9 to 11, where it will reach a height of 20 feet with a …
Growing Lime Trees From Seed
In addition to nursery-grown plants, grafting is probably your best bet when growing lime trees. However, most citrus seeds are relatively easy to grow, including those from limes. While it’s possible to grow a lime tree from seed, don’t expect to see any fruit right away. The downside to growing lime trees from seed is that it can take anywhere from four to ten years before they produce fruit, if at all.
Growing Lime Trees from Seed
Since many lime seeds are obtained from purchased fruit, they’re most likely hybrids. Therefore, planting lime seeds from these fruits often will not produce identical limes. Polyembryonic seeds, or true seeds, will generally produce identical plants, however. These can normally be purchased from reputable nurseries specializing in citrus trees.
Keep in mind that other contributing factors, like climate and soil, also affect the overall production and taste of lime tree fruit.
How to Plant a Lime Seed
There are a couple of ways to grow a lime tree from seed and knowing how to plant a lime seed is important for success. You can plant the seed directly in a pot of soil or place it in a plastic bag. Before planting lime seeds, however, be sure to wash them and you may even want to allow them to dry for a couple days, then plant them as soon as possible. Plant seeds about ¼ to ½ inch deep in containers with well-draining soil.
Likewise, you can put seeds in a plastic baggie along with some moist soil. Regardless of the method you choose, keep the seeds moist (not soggy) and place them in a warm, sunny location. Germination usually occurs within a couple of weeks. Once seedlings have reached about 6 inches tall, they can be gently lifted and placed in individual pots. Be sure to provide winter protection, as lime trees are very cold sensitive.
If you don’t want to wait so long for lime fruit production, you may want to consider other means of growing lime trees, which will usually bear fruit within three years. However, growing lime trees from seed is an easy and fun alternative to experiment with, keeping in mind that as Forrest Gump would say, “like a box of chocolates, you never know what you’re gonna get.”
In addition to nursery-grown plants, grafting is probably your best bet when growing lime trees. However, most citrus seeds are relatively easy to grow, including those from limes. Learn more in this article.