Orange/citrus seeds — I have best success sowing freshly extracted seeds. Use a well-draining mix. They sprout in 3-4 weeks. Dried up seeds are not always viable. My understanding is it can take 7 years or so before they even start to bloom, and also they can be crossed/hybrid and not be true to parent fruit characteristics.
I have many citrus plants of all kinds (lemons, limes, oranges, grapefruits), at different ages, and sizes all started from seeds — they Are fun to grow and make good winter houseplants. They do best outside during the summer. There are different minimum temperature ranges that they tolerate, and they need to be brought inside about while lowest temps are 10 degrees above, otherwise they shut down and lose leaves, etc.
None of them has fruited yet. One or two have started to bloom, but, as typical of fruit trees, they do not set fruit until they are older, even after they start to bloom. Mine are not cared for very well, usual agricultural recommendation is for pretty heavy fertilizer application, and I don’t do that. Also tend to let them dry out and stay in too-small containers for too long. So my own experience is not indicative of how they would grow under ideal conditions. But only thing they suffer from is overwatering. Otherwise pretty forgiving and takes well to pruning.
While waiting for blooming/fruiting, the leaves of different citruses have distinct fragrances and can be used in teas, as herbs for cooking, and body care products.
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