This may sometimes be due to seed dormancy, a condition that prevents the seed from germinating even when it is perfectly healthy and all conditions for germination are at optimum. The natural method is to sow the seeds out of doors somewhere where they will be sheltered from extremes of ...
Hesperis Lupin Phacelia Sunflower Zinnia Honesty Malope Phlox Sweet William Ipomoea Nicotiana Rudbeckia Tithonia Nigella Scabiosa Wallflower