Mayfire
Nectarine in the US

Nectarines are usually grown from the stone, which you'll need to stratify first – that just means giving them a cold period, like in your fridge for a few months, before you plant them out. Sow them about an inch (2.5 cm) deep in a pot, indoors is best to get them started. The timing really depends on your USDA zone, you know what I mean. For zones 3 and 4, April or May is a good bet. Zone 5 can start March through May. Warmer zones like 6 and 7, you're looking at March, April, or even October, November. Zone 8 adds February, and zones 9 and 10 can start earlier in winter, January or February, or later in the fall. Keep the soil warm, around 65-70°F (18-21°C) to get them going.

Once your little nectarine seedlings are big enough to handle, like, a few inches tall, you can pot them up into individual containers. These trees take a good while to get going, about two years to harvest from seed. When the risk of your last frost is well past, and they're a good size, harden them off properly before planting them out in their final spot. Choose a sunny, sheltered place on your plot, giving them plenty of room, maybe 10-20 feet (3-6 meters) apart depending on the variety and how you plan to prune them. Some folks grow dwarf varieties in large containers too, which is a good option if space is tight.