Hands down lettuce is the easiest and quickest thing to grow in an aerogarden. Basil is the next easiest. I'll defer other herbs to the rest of the crew here. I'm trying tomatoes, cucumbers and peppers for the first time, so I can't comment yet....
Lettuce grows to first harvest in an Aerogarden in 3-4 weeks, more like 6-8 weeks outdoors in soil.
Toy choi (dwarf pak choi) and mustard greens grow to harvest size in 30 days, soil or hydroponic.
In soil, small radishes take 3-4 weeks.
P.S. The quickest fruiting veggie I know of is zucchini, with cucumber a close second. (About 7 and 9 weeks.) They're big plants, though. You'll have noticed all the ingenuity around here going into mastering the hydroponic cucumber.
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