Celery takes an especially long time to grow, usually at least 90 days. If you live in an area that regularly receives frost in the late fall/ and early winter, you will need to plant your celery indoors if you want to grow it. It should be started 10 weeks before the last frost date in your area. Once you have started it growing, it will require consistent watering to successfully bring it to edible maturity. It has a reputation for being difficult, but if you are successful, it is worth the effort.
Soak the celery seeds you wish to plant in a small amount of water overnight. Then pour the water over the potting mix in your small pots.
Cover the seeds lightly with soil, 1/4 of an inch at most. Celery seeds need light to germinate.
Water the pot with a mister bottle. Watering with a mister bottle ensures that you do not disturb the seeds.
Cover the pot with a little plastic wrap and place in a sunny window. South-facing windows are best, if you have them.
Water every couple of days or any time the soil looks dry. Check the tray at the base of the planter. If it contains a lot of water, the pot probably does not need more water.
Remove the plastic wrap when the seeds send up sprouts. Continue to water every couple of days.
Thin celery seedlings after the second set of true leaves appears on each of the seedlings. Transplant or dispose of the thinned seedlings. Apply fertilizer according to the manufacturer's instructions.