Onions are plants in the genus, Allium. They are eaten as vegetables. Most species of onions have bulbs that people can eat. They have a strong flavour and a very distinctive smell.
Onions have been grown for a long time. They were probably first grown in Ancient Egypt, together with leek and garlic, but maybe earlier. Now, most of the world's cultures eat onions.
Farmers and gardeners can grow onions from seeds or from bulbs. If they plant seeds, they must later pull out most of the young plants so the rest can grow better. This is called 'thinning'. A different way to plant onions is to plant young bulbs. This is faster, but the onions that grow this way are weaker than the onions that started as seeds.
When cutting an onion, the cells of the onion start to open. Then, some chemicals react. When one chemical floats through the air and reaches your eyes, they sting.There are ways to keep the chemical away. You can:
Cut the onion under water
Keep the onion in the fridge, and cut when it is cold
