These are the ones I regrow the very most, I always have a mason jar of green onions regrowing above my kitchen sink. The technique is quite simple. Once you are done with them (any of the above four), simply place the root end in a jar of water & it will begin to regrow within just a few days. Just make sure to replace the water with fresh as need be. 15 Foods That Can Be Regrown from Scraps
5. Lemongrass You can regrow lemongrass the same way you regrow the green onions. Simply place the root ends in a glass of water, refreshing the water as needed. You will want to wait to harvest your lemongrass until it is about 12 inches tall.
6. Ginger Plant a small chunk off of your piece of ginger in potting soil with the newest buds facing up. Ginger enjoys non-direct sunlight in a warm moist environment. Before long, it will begin to regrow shoots and roots. Once the plant is established and you’re ready to harvest, pull up the whole plant, including the roots. Remove a piece of the ginger, and re-plant it to repeat the growing process.
Here is a good video on replanting ginger:
7. Potatoes Pick a potato that has a lot of good formed eyes, and cut it into 2-3 inch pieces, taking care to be sure that each piece has at least 1-2 eyes on it. Leave the cut pieces to sit at room temperature for a day or two, which allows the cut areas to dry. Potato plants thrive on a high-nutrient environment, so it is best to flip compost into your soil before you plant. Plant your potato pieces about 8 inches deep with the eye facing up. Cover it with 4 inches of soil, leaving the other 4 inches empty. As your plant begins to grow and more roots appear, add more soil.
8. Sweet Potatoes You will need sweet potatoes with good formed eyes, just as you would want with a regular potato. You can bury the entire potato or use pieces under a thin layer of topsoil in a moist place with plenty of sun. When the shoots begin to reach a height of four inches you will need to replant the sweet potatoes, allowing them about 12 inches between each another. It takes about 4-6 months to grow sweet potatoes this way.
9, 10, 11, & 12. Romaine Lettuce, Celery, Bok Choy, & Cabbage These all are regrown by placing the roots in a dish of water. Cut the leaves or stalks off to about an inch above the roots. Place the root end in a dish of water. Make sure that the roots are inside of the water, but do not submerge the rest of the plant. Place in a sunny window & spray with water 1-2 times a week to keep the top of the plant moist.
13. Onions Onions are one of the easiest vegetables to regrow from scraps. Just cut off the root end of your onion, leaving a 1’2 inch of onion on the roots. Place it in a sunny location in your garden and cover the top with soil. Make sure to keep the soil moist by watering when needed. As you use your home-grown regenerated onions, keep replanting the root ends you cut off, and you’ll never have to purchase onions at the store again.
14. Garlic You can re-grow a plant from a single clove. Simply plant it with the root-end down. Sit the plant in a sunny window. Once established, cut back the shoots and the plant will put all it’s forces into producing a nice garlic bulb – full of flavor & capable of repelling sparkly vampires. You can repeat this process with a clove from the new bulb you have just grown.
15. Pineapple To re-grow pineapples, you will need to remove the green leafy part at the top and take care that no fruit remains attached. Either hold the crown firmly by the leaves and twist the stalk out, or you can cut the top off the pineapple and remove the remaining fruit flesh with a knife. If you do not remove all the fruit parts, it will rot after planting and will likely kill your plant. Carefully slice small, horizontal sections from the bottom of the crown until you see root buds (the small circles on the flat base of the stalk). Remove the bottom few layers of leaves leaving about an inch worth of them at the bottom of the stalk. Plant your pineapple crown in a warm and well drained environment. Water your plant regularly at first. Once the plant is established, you can cut down to about once a week. You will see growth in the first few months but it will take about 2-3 years before you are able to harvest.