Source(s): plant onion bulb grow onion bush tree grow onion: 0 0. Most people think that planting the onion is very difficult but the onion bottoms which we throw in the trash can be used in the growing of fresh onion plants. The bulb is the onion, and the onion is the bulb. You can plant a sprouted onion, but it might be better to separate it into parts before planting. Usually 3 months. 5 years ago. Onions, as a previous poster said, are bulbs. How Many Onions Grow from One Bulb? It's an onion. Great! You are planting it to grow it into a larger onion. Onions are one of the most indispensable and flavorful ingredients you can cook with. You can chop up these leaves and use them for cooking to give a dish some nice onion flavor. This waste is a means of planting onions. A lot of people are quite confused by this concept, especially when it comes to wondering how you produce MORE onions for consumption. Onion sets are small onions that have been pregrown and are ready to grow on to reach maturity in a shorter time frame. Also does it grow more than one onion? The onion start itself is just a small onion bulb. Please feel free to ask any other questions you may have about growing onions FAOSTAT output for dry onion yield in Eastern Africa 1995 to 2013 (Hg/Ha) Table of onion yields for Eastern Africa between 1995 and 2013, converted to metric tons per acre. You can also harvest the green leaves on top of the onion when they get larger as the plant grows. The "garlic chives" that you got would eventually have grown into a garlic plant with a seed pod at the top. Holly. To grow onions in your own garden is very easy. If you do so, you can get one or more smaller onions to grow. You can theoretically create an endless supply of onions without ever having to buy bulbs or seeds, and if you're as big of an onion lover in the kitchen as I am, you'll have a full bed of onions in no time. For many areas in the world the growing season isn’t that long so it makes growing onions from seeds very challenging. This Instructable outlines how to grow fresh onion plants from discarded onion bottoms that would otherwise be thrown in the trash. Onions have a multi year life cycle and won't make an edible bulb from seed right away.However, in the major onion growing areas of the US, onions typically are planted from seed. Did you know that all plants reproduce only after their own kind? One onion, one bulb. One bulb, one onion.