Lemons will stay fresh for months if you keep them in a covered container filled with cold water in the refrigerator. Be sure the container has a tight fitting lid! Change the water every week or so.
The next time you have green onions, don't throw away the white ends. Simply submerge them in a glass of water and place them in a sunny window. Your onions will begin to grow almost immediately and can be harvested almost indefinitely. We just use kitchen scissors to cut what we need for meals. I periodically empty out the water, rinse the roots off and give them fresh water.
Green Onions - The next time you buy or pull green onions from your garden – don’t throw away the bottom bulb portion. Cut off what you need for your recipe, dinner, etc then toss the bulbs into a glass with a bit of water. They’ll begin to grow and give you new green onions to use!