Rudbeckia can be started indoors, from seed, about 6-8 weeks before last expected frost. Perennial varieties will germinate best if stratified after planting. You can do this by keeping them in the refrigerator or a similarly cold place for 4 weeks after planting. Then move them back to a warm spot (70ºF-72ºF) until seeds actually germinate. Rudbeckia can also be direct seeded in the garden once daytime temperatures remain around 60 degrees F. Of course, plants can be purchased and transplanted. Barely cover the seeds with soil, whether planting indoors or out. Gaillardia is one of those plants that need exposure to light, to germinate. If you are broadcasting the seed over a wide area, you can simply rake it around and then water well, making sure it comes in good contact with the soil. Blue flax germinates best when direct seeded (although you can start seed indoors for transplanting). Sow in mid to late spring or early fall. Fall sowings should bloom the following year. Cover with about 1/4" of soil and thin plants to 6" apart, once they are 1-2 inches tall. You will have better germination if you treat the seed, prior to planting. Either soak overnight in warm water, scarify the seed and soak for several hours, or chill the seed for 7 days prior to planting by folding the seed in a damp paper towel, placing the towel in a plastic bag, and then placing the bag in the refrigerator. Plant treated seeds in spring to early summer. You could also plant seeds in the fall and let nature chill them for you. Dianthus seeds don’t require much fuss. You can start them indoors, 6-8 weeks before your last frost date, and move them outside after danger of frost has passed. Since dianthus can stand a little chill, you could even seed them in the garden, right around your last frost date. Barely cover with soil and keep the bed moist until the seedlings emerge. To start primrose seed outdoors, follow the same procedure, but be sure to sow during a cool season, leaving several weeks for the newly sprouted plants to grow, before the weather will become hot (80 degrees F), so the young plants will have time to adjust. After chilling, sow the seeds by barely covering them with soil. Keep the seed flats in a warm area (70-75 degrees F) and then be patient. If can take 3 weeks to 3 months for the seeds to germinate. Be sure to keep them warm and moist the whole time. Cover seed with about 1/8 inch of soil and keep the soil moist. Seeds should germinate within 10-20 days. That’s it! You can also direct seed in the garden after any danger of frost has passed. Be sure to keep the soil moist.
