Growing an orange tree — or any citrus tree — from a seed is no more difficult than growing a bean plant from seed. In fact, tangerine seedlings have shared a pot with a houseplant near my rocking chair, evidently “planted” casually as someone ate the fruit while sitting in the chair. And it’s not unusual to find an overenthusiastic grapefruit seed sprouting while still inside the fruit.
SEEDS ARE EASY
There’s only one secret to growing citrus from seed: Don’t let the seed dry out. Helpful, though not critical, would be to soak the seed for a couple of hours before planting it, to leach out any sprouting inhibitors that might be present. After all, the seeds don’t usually sprout inside the fruits, so something — perhaps an inhibitor — in or near the seeds must be preventing sprouting. Another possibility is that the seeds are held back by low oxygen levels within the fruit.
Once the seed has been soaked, plant it like a bean seed, about three-quarters of an inch deep. Do this in a pot filled with the same potting soil you would use for houseplants or any other seed.
Being tropical (again like a bean plant), citrus seeds need warmth to sprout. A minimum of 60 degrees Fahrenheit is good enough; 80 degrees would be ideal. Once the seed sprouts, which should not take longer than a few weeks, move the developing seedling to a sunny window.
BUT WILL IT TASTE GOOD?
To end up with a good-tasting fruit from a tree grown from seed has always been a tenuous proposition. All apple, pear, plum and peach varieties are clones, propagated by grafting or cuttings.
A tree grown from seed will bear fruits different from — and probably worse — than the tree that bore the fruits that bore the seeds. That’s because plants grown from seeds, in contrast to plants propagated by grafting or cuttings from stems, leaves, and roots, represent the commingling and shuffling around of genes of the parent tree and whatever other variety pollinated the flower that preceded the fruit.
However, citrus has the quirk, known as apomixis, of frequently producing seeds that are not the result of pollination, but that develop from the same kind of cells that make up the rest of the plant. Bingo: a seed that is genetically identical to its mother and hence will bear identical fruit when grown into a tree.
BUT WILL IT BEAR FRUIT?
Sorry, a few hurdles still stand in the way.
For one thing, not all the seeds even in a single fruit are necessarily apomictic, although sometimes it is possible to identify those produced by pollination by their weaker growth.
Secondly, citrus, like other plants, must go through a juvenile phase before becoming old enough to bear fruit. This phase, marked in the case of citrus by thorny branches, can last many years.
And finally, even after a citrus tree gets old enough to potentially bear fruit, it won’t do so except under good growing conditions, which are difficult to achieve unless you garden in a subtropical or tropical climate. When growing citrus in a pot, which is necessary in cold climates, more attention must be paid to providing sufficient food, water and light.
With that said, even a barren citrus tree is worth growing for its glossy, vibrantly green leaves. Growing a citrus tree from a seed is an especially nice long-term project for a child. The plants are fast-growing, and if interest begins to wane, just crush a leaf. The aroma offers a mouth-watering hint of the taste of fruit possibly to come.