Since The juju potions have come out ive been keeping stats on all of my farming runs of torstol. Over 565 herbs planted ive grown 5182 herbs, averaging 9.17 herbs per seed including deaths and gained about 27mil just from selling the herbs (i dont know how many free seeds i got from the scroll of life, but can only assume around 56 from the 1/10 ratio given.) i would say that you just had some less than desirable luck and the small sample size doesnt help, just keep your hopes up and im sure you will have some better luck eventually.