Celery is a temperamental plant that does not do well with excessive heat or cold. This makes growing celery indoors an excellent option. By keeping your celery at room temperature and out of hot late afternoon sunlight, you can get a better harvest from a healthier plant.
Fill a wide planter with rich potting soil. Celery does best in nutrient-rich soil.
Mix the celery seeds with sand and spread them evenly over the potting soil. Then, cover the seeds with a thin layer of potting soil.
Put your planter in a north- or east-facing window. Keep the soil moist, but not soaked.
After about 2 weeks, transfer the sprouted plants into individual containers. Pull them out carefully to avoid damaging the roots.
Fertilize the celery with a fertilizer such as the one linked to below. Add it according to instructions.
Let the celery grow for 100 days. Then, harvest it by pulling the whole plant up.