Growing an orange tree from a seed is surprisingly simple and it is something that anyone can do with some tips and placing themselves near a sunny window and in a pretty warm place. Getting the seed is probably the hardest part of the whole operation. You can either buy your seeds online on the internet via a specialized supplier or if you only want a few seeds, you can of course collect them directly in the fruits.
Once you have cut the fruit, open the slice and expose the seed, remove the seeds and rinse well any fruit residue. You must always work from clean seeds collected from fruiting bodies because they normally contain chemicals that actively prevent seed germination.
Place the “clean” seed in a glass of water and first discard those floating on the surface as they will not be viable. The smallest seeds can rise to the surface because air bubbles form on the surface of the seed coat.
You can also throw out all the seeds that are too small because they are unlikely to have enough energy to germinate successfully. Once you have selected your seed, it can be dried and stored in an envelope until needed.
The seeds of oranges, like all citrus fruits, have a natural dormancy period and it will take a cold period to trigger germination. They can germinate without this cold period, but the results will be poorer.
Fortunately, most citrus fruits are transported using a refrigeration system so that they have already been “pre-chilled” before they reach you. Otherwise, this can be overcome by placing the seed in the crisper drawer of the refrigerator and leaving it for a few weeks. First, protect the seeds in paper by folding them back a few times, then place them in a plastic bag or a sterile food container before leaving them in the refrigerator.
After about three weeks, even though they can be left there for a month, the seeds can be removed from the refrigerator and are ready for repotting. Soak the seeds for a few hours or more before planting them in 8 cm pots. Sow only one seed per pot using a good quality compost with water and good drainage.
If you can, place the pots in a heated propagator at a temperature of 16 degrees Celsius, otherwise position the pot to a clear, warm position like a kitchen window. Water regularly so compost does not dry out, but make sure the compost is never waterlogged.
Germination should occur at any time between 4 to 6 weeks, but do not worry if it takes a little longer as the orange seeds are known to take several months before they show up.
New plants can be left in their pots for another 3-6 months, depending on how they grow, but once they are about 10 to 12 cm, they can be potted on the next larger pot. As long as there are no jellies planned, young orange trees can be put outside to harden over the next two to three weeks.
During the growing season, they can be watered regularly and feed with a water-soluble fertilizer once a week. You can often get yellowing of leaves with orange trees because of chlorosis, but this can be treated by feeding an acidic vegetable food.
Unfortunately, orange trees are not particularly resistant to cold even if they tolerate temperatures as low as 4 or 5 degrees Celsius for short periods without much difficulty.
For northern European countries, it is best to keep all the orange trees under protection during winter periods, but once the threat of frost is over, they can then be hardened for a few weeks before spending the rest of the growing season outside in full sun.