For most of controlled environment agriculture's commercial history, the crop question had a default answer: leafy greens. Fast-growing, light-dependent, high-turnover, and well-suited to hydroponic systems, lettuce and baby leaf mixes were the obvious proof-of-concept for a new industry trying to demonstrate that indoor farming could work at retail scale.

They still do. Leafy greens account for 39% of all crop-tagged articles in the iGrowNews CEA database — 63 of 162 entries — comfortably ahead of every other crop category. The overwhelming majority of CEA operators globally still grow some combination of lettuce, baby leaf, spinach, herbs, or microgreens. The infrastructure was built around these crops, the retail relationships were forged around them, and the agronomic knowledge base is deepest here. Leafy greens are not in retreat. They are the floor.