Choose a healthy onion with a firm base and visible roots or a fresh root end
Cut off the bottom 1 to 2 inches of the onion, keeping the root plate intact
Place the cut base in a shallow dish with a little water, root side down
Keep the dish in a sunny windowsill or bright location
Change the water every 1 to 2 days
Wait for green shoots and roots to grow
Plant the rooted base in soil with the top of the base just below the surface
Water the soil lightly and keep it consistently moist
Place the pot or garden bed in full sun
Allow the onion to grow until the tops yellow and fall over
Pull the onion from the soil and let it dry before storing or using