A fast and easy spring crop, radishes are ready to harvest 25 to 30 days after sowing. In fact, if you wait too long to pull them up, they become pithy.
Although most varieties of kale take 50 to 65 days to mature, the tender baby leaves can be picked 25 days after sowing.
Most varietes of leaf lettuce mature in 40 to 50 days. This crop is four weeks old and almost large enough to sample.
Green onions and bulb onions both come from the same type of sets (small bulbets). It takes up to six months for onion bulbs to mature, but if you just want green onions, prepare to pluck them out of the ground three to four weeks after you plant the sets.
Depending on the variety, it can take anywhere from two to three months for turnip roots to develop, but many cultivars need only a month or so to produce delicious leaves: 'Just Right', 28 days to harvest for greens; 'Alltop' and 'Topper', 30 days.
Spinach is typically ready to harvest in 45 to 50 days. Plain-leaf types are easier to wash and tend not to retain soil particles.