can any one tell me is it possible to grow kumara or sweetpotato this way i know we can grow corn tomatoes cauliflower this way but then these all grow above ground any info would be appreciated
Not being an authority on hydroponics, i would say that any tuberous plants such as potatoes would rot. However, plants do adapt and will produce more fleshy roots in water. I have some very successful houseplants which are grown hydroponically....weeping figs, palms, devils ivy etc and they thrive....i've had one ficus for 8 years and it grows in clay granules (leca) and water.
Hydroponics isn't just for above ground plants. You can grow potatoes as well with the help of hydroponics. For more information refer www.advancednutrients.com/hydroponics/article
s/vegetable-gardening/
It has very informative Vegetable Gardening articles.