This side-by-side comparison of a soil-grown and hydroponically grown basil isn’t meant to be a proof that hydroponics always gives better results than growing in soil. The pot with the soil-grown plant (the one on the right) is simply too small to offer ideal growing conditions, which makes the comparison unfair.
However, the sheer difference (notice the huge leaves of the hydroponically grown basil) between the two plants is striking, especially taking into consideration that the hydroponic plant was started as a cutting from the plant on the right, although now, they’ve come to look almost as two different varieties.
At the very least, it suggests that it is possible to grow a healthy looking plant without soil, i.e. hydroponically, but also that one can do so without any pipes, pumps, electricity, moving water, aeration or other features considered indispensable by many hydroponic growers.
In fact, the only requirements are: a non-transparent vessel (to prevent the growth of algi) filled with a full hydroponic nutrient solution, a net-cup with a non-soil substrate such as rockwool, and a gradually forming humid-air space between the bottom of the net-cup and the water-nutrient surface allowing air-exposed roots to absorb oxygen.
Maintenance is needed only if and when nutrient solution risks evaporating almost completely before the plant is harvested. In other words, the bigger the vessel and the shorter the life-span of the plant, the less maintenance we need.
In this case, since the thai basil is grown in a glass of merely 500ml, topping up nutrient (or replacing the whole solution) once every few weeks is unavoidable.
With bigger containers though, this problem can be reduced to minimum. I’m not saying that every plant can be successfully grown using this ultra-simple non-circulation method, but thai basilic certainly can.