You know, I have planted nasturtiums in rich soil and they flower fine. I think the secret is, only using organic fertilizers such as manure and compost, no chemical fertilizers. I am no expert here, all I know is what works for me. I planted them in pots and in my veggie garden, where the only fertilizers I use are manure, bone meal and compost. The soil is quite rich, but there are no chemical fertilizers at all. Not only did the veggies produce a large crop, but the nasturtiums bloomed like crazy too. They are great in the veggie garden by the way, not only are the leaves and flowers edible, but supposedly they deter several kinds of pests.

Oh goodie. That is good to hear. I do hope my seeds will sprout and this will be a success. Thanks for taking the time to answer my question.