Please log in the sprouted kitchen your username or email to continue. By using our site, you agree to our cookie policy. How is where trusted research and expert knowledge come together. This article was co-authored by Steve Masley.
Steve Masley has been designing and maintaining organic vegetable gardens in the San Francisco Bay Area for over 30 years. He is an Organic Gardening Consultant and Founder of Grow-It-Organically, a website that teaches clients and students the ins and outs of organic vegetable gardening. There are 9 references cited in this article, which can be found at the bottom of the page. How marks an article as reader-approved once it receives enough positive feedback. This article has been viewed 343,613 times. If you notice a green sprout emerging from the top of an onion, it means it’s trying to regrow.
By separating the sprouts inside an onion’s layers and planting them in good soil you can grow multiple new onions within a single season. Peel off sprouted onion’s papery outer skin. Dig your fingernails into the skin at the top of the onion bulb and rip it off piece by piece. Discard the skin when you are done. Use a knife to cut the onion’s layers from the sprouts. The sprouts grow at the center of the onion bulb. Slice through onion’s layers vertically while avoiding the sprouts.
Repeat on the other side then carefully slice off the onion’s layers. If you don’t have a knife, peel off the onion’s layers individually with your hands. You can eat the onion layers if they are firm and crisp, though make sure you wash them first! If they are soft and mushy discard them. You will likely find a few sprouts growing at the center of the onion bulb.
Some will protrude from the bulb, others will not. Use your hands to gently separate the sprouts from one another so they don’t need to compete for space. Given proper care, each sprout can grow into a brand new onion bulb! Place the sprouts in water until roots grow.
You can keep the sprouts in individual cups, glasses of bowls of water. Within a few days white roots will form at the bottom of each sprout. If white roots are already present you can plant the sprouts straight into the soil. If you see dry, brown roots on a sprout, it means they are already dead. You want to wait for new white roots to form. Dig an individual hole for each sprout, and cover it so only the green part sticks out. Consider applying a thin layer of mulch to the soil to aid the growth process.
Whether indoors or outdoors, ensure the plants get ample sunlight. If you live in a cold climate, plant the sprouts in pot plants inside and gradually introduce them to the outdoors. The onions have been inside for some time and will need to adjust. During the winter in cold climates keep the plants indoors at all time to ensure they stay alive. Expect to see onion bulbs form after 60-80 days! Water the plants every few days.
Onions are resilient, but need plenty of water to grow. Pour a little water from a gardening can, or use a hose, on the soil around the onions, not the plant itself. Ensure the soil is well drained. Check the plants for weeds every day and remove any that appear. As the onions grow, weeds will inevitably emerge around them. Wear garden gloves and ensure you pull the weeds out by the roots so they don’t grow back.
Treat the plants twice a week with fungicidal spray. The spray will prevent harmful fungi from destroying your plants and ensure they remain healthy. A few short sprays on each plant should be enough. If you prefer not to use synthetic compounds, oxidate or copper sprays are good alternatives. Look for signs that the onions are ready for harvest.