Purchase a well-draining soil mix and a large pot with holes in the bottom from a plant nursery. Fill the pot with the soil to about halfway full—you will fill it the rest of the way when you plant the onion cutting.  You can also plant your onion bottom outside if your garden has well-draining soil. You can test to see if soil is well-draining by digging a 12 in (30 cm) hole in the soil and filling it with water. If the water drains in 5-15 minutes, the soil is well-draining. When the onion cutting grows white roots from the bottom, position it in the center of the soil. Fill the rest of the pot with soil over the onion until 1–2 in (2.5–5.1 cm) from the top of the pot.  Depending on your preference, you can keep the onion cutting indoors or outdoors in sunny weather. If you plant the whole cut bottom as one piece, you may get more than one new onion but they will likely be crowded together and small.  The number of plants a single onion can grow will vary from 1-6, the onion pictured above can be divided into two.  To get multiple full size new onions from a single onion bottom, use a sharp knife to divide the onion bottom, leaving a portion of the roots on each section, as well as the leaves if it has started sprouting. Watering the onion cutting helps it adapt to its new environment and grow roots faster. Give your onion enough water that the soil is damp to the touch, but not soaking wet. Onions thrive in soil with a high nitrogen content. Spray nitrogen fertilizer directly into the soil and mix it with your hands to give your onion the nutrients it needs to grow.  You can buy nitrogen fertilizer from most garden stores or nurseries. Check the label to determine how much fertilizer to spray into the soil.
املأ أصيصًا بتربة جيدة التصريف. ضع قطعة البصل في التربة واملأ الأصيص بالتربة. اسقِ قطعة البصل مباشرة بعد زراعتها. رش الأسمدة النيتروجينية على التربة بعد سقايتها.