How to grow garlic in water
If you want to grow garlic but don’t have the space for a garden or a large pot, you can try growing garlic in water. Growing garlic in water is a great way to have fresh garlic available when you want it, without the hassle and expense of going to the grocery store. Be aware that when you grow garlic in water, you will not be able to grow whole new cloves. Instead, you will be able to grow leaves (also called garlic sprouts) on top of a garlic clove. These sprouts have the texture of green onions but with a slight garlic flavor.
Purchase 1 or more garlic cloves that have begun to sprout. When the garlic sprouts, the clove, still covered in its white protective wrapping, will produce a small green shoot from the top.  Inspect a few different cloves until you find some that have sprouted. While you can try growing unsprouted garlic in water, you are more likely to succeed if you use cloves that have sprouted.
You can find suitable garlic cloves at your local grocery store. However, for better quality garlic that will produce larger, tastier sprouts, visit your local farmers’ market.
Place the sprouted clove in an 8 oz (230 g) glass jar. Orient the garlic so that the sprouted end of the clove is pointing up.  It is best to grow the garlic sprouts in a clear glass container, so you can see the garlic sprouting from the roots and starting to grow.
If you don’t have a glass jar, you can use a drinking glass or shot glass instead, if that’s more convenient.
Image titled Growing garlic in water, step 3
Pour water into the jar until the bottom of the garlic clove is covered. You can use warm tap water. Depending on the size of your garlic clove, you will need to put about 1/2 inch (1.3 cm) of water in the jar.  Avoid using extremely hot water, or you will damage and possibly kill the clove.
If you submerge the garlic completely under water, it will die and rot.
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Leave the pot on your windowsill for 4-7 days. Make sure the sprouted garlic clove gets plenty of sunlight.  If the top of the growing garlic shoots start to turn brown or wilt, remove the glass from the sun for 1-2 days.
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Change the water if it turns dark brown. Brown, cloudy water will be unhealthy for garlic and can stunt sprout growth. To change the water, remove the garlic from the jar with one hand and use your other hand to drain the water from the jar. Then put the clove back in the jar and fill it with water. Be sure not to overfill the jar with water. 
You should only need to change the water 1 or 2 times before the sprouts are ready to be harvested.
Harvesting And Looking After Water Grown Garlic
Let the garlic sprouts grow until they are at least 7.6 cm tall. Keep an eye on the garlic as the green shoots begin to emerge from the top of the clove. The thin shoots will emerge and grow quickly. When the sprouts are 3 to 7 inches (7.6 to 17.8 cm) tall, they are ready to be harvested.
If you harvest the garlic sprouts prematurely, they will be bitter and taste unpleasant.
Cut off the top third of the garlic shoot with a pair of kitchen scissors. So if your shoot is 3 inches long, cut off the top 1 inch. This will be the tastiest and least bitter part of the garlic shoot. 
In most cases, you will only be able to harvest the garlic sprouts once. It is unlikely that the garlic clove will produce new shoots after harvesting.
Only cut the amount you plan to use for a specific meal. If you try to store already cut garlic in your refrigerator, it will dry out and lose its flavor.
Add garlic shoots to savory dishes. Once you’ve harvested the tops of the garlic sprouts, use your scissors to cut them into small 0.64 cm ( 1 ⁄ 4 inch) pieces. Then add the sprouts to any savory dish you like, including baked potatoes, soup, or scrambled eggs. 
Also try adding chopped raw garlic sprouts to salads, salsas, egg dishes