The antioxidant, phytonutrient, and vitamin content of basil grown in water (hydroponic) is compared to basil grown in soil.
Herbs and spices are among the healthiest plants to consume. See one of my favorites, for example: Antioxidants in a Pinch, and Antioxidant Content of 3,139 Foods. The glucosinolates I mention are the broccoli compounds featured in videos such as Broccoli Versus Breast Cancer Stem Cells; Sulforaphane: From Broccoli to Breast; and The Best Detox. For how our food crops have been doing in general over the years, see Crop Nutrient Decline. And for more on the organic question, see Can Pesticides Be Rinsed Off? and Fungal Toxins in Apples.
For further context, check out my associated blog post, Antioxidants in a Pinch: Dried Herbs and Spices.