(Clone) Three Weeks no roots

I took some clones off a a Purple Kush and I cloned them around the first of March but still no roots as this is the end of March. I used root starter and all the normal BS. I have them sitting in water, maybe I should just put them in soil? This is the first time I haven't been able to get a plant to take root.

Any advise O Guru of the green plant!