You can try growing olives from seed but the chances of success with store-bought fruit are very low. Supermarket olives have been cured in salt, brine, or lye. These treatments kill the seed inside the pit and make sprouting almost impossible.
I tried this myself with pits from a jar of Kalamata olives. I planted about 50 of them and waited for months. Not a single one sprouted no matter what I did. The curing process had destroyed any chance of olive seed germination before the jar ever reached the store shelf.
Fresh uncured olive seeds have low germination rates too. Only 30 to 50% of fresh pits will sprout under the best conditions. The hard shell protects the seed but also blocks water and air. Cured pits drop that rate down to nearly zero since the chemicals damage the embryo inside.
Lye treatment does the most damage to seeds during the curing process. The caustic solution burns through the shell and reaches the seed itself. Brine-cured olives fare slightly better but still have very low rates of success. Water-cured olives keep more viable seeds but these are hard to find in stores.
Better methods exist for propagating olive trees if you want your own plants. Buy grafted trees from nurseries for the fastest route to olives. These will fruit in 3 to 5 years instead of the 8 to 15 years a seed-grown tree needs. The grafted trees also match the variety on the tag which seeds won't do.
You can take cuttings from a mature olive tree if you know someone who grows them. Semi-hardwood cuttings work best when taken in late summer. Dip the cut end in rooting hormone and plant in sandy mix. I got four out of six cuttings to root this way and they grew into healthy trees.
If you still want to try seeds find fresh uncured olives from a farmers market or olive grove. Score the shell with a file to help water get in. Put the pits in a bag with damp sand and refrigerate for 8 to 12 weeks to cold-stratify them. This tricks the seed into thinking winter has passed.
Skip the supermarket and buy a grafted tree if you want olives in your lifetime. Seeds from cured fruit will waste your time and effort with nothing to show for it. Grafted trees or cuttings give you a much better path to growing your own olives at home.
Read the full article: Growing Olives: Step-by-Step Plan for Home Gardeners
