Radishes: Radishes are one of the quickest vegetables to grow. They can be ready for harvest in as little as 3 to 4 weeks.
Lettuce (Leafy Greens):Varieties of lettuce, such as looseleaf or baby greens, grow rapidly and can be harvested within 3 to 6 weeks. They are well-suited for container gardening too.
Spinach: Spinach is another leafy green that grows quickly. You can start harvesting baby leaves in about 3 to 4 weeks and full-sized leaves within 6 to 8 weeks.
Green Onions (Scallions): Green onions are known for their rapid growth. You can harvest them when they are about 6 to 8 inches tall, usually within 3 to 4 weeks.
Bush Beans: Bush beans are a fast-growing option among legumes. Depending on the variety, you can expect to start harvesting beans in around 45 to 60 days.