Flowers:

Plant seed twice as deep as it is long as a general rule.  Most flowers benefit from being started indoors 6-8 weeks before being transplanted outside.  Transplant when they have at least 3 true leaves for best success.  Harvest flower stems regularly to encourage longer bloom period.  Some very small seeds require light to germinate (like Strawflowers, Marigold & Gallardia)

Calendula: direct seed in late spring or grow transplants.  Can tolerate light frost.  Keep picked.

Cosmos: Can be direct sown in garden. Grows to a large (4’) bush.  Tolerates light frost.  Self sows readily.

Marigold: tiny seeds best sown indoors and transplanted out in late spring.  Space 12-18” apart

Poppies: direct seed as early as possible

Sunflower: direct seed in late spring.  Allow plenty of room (12-18”) for them to get tall. Protect seed from birds if you hope to harvest any.

Zinnia: Sow indoors 6 weeks before transplanting outdoors 12-18” apart.  Harvest regularly to prolong bloom.   Grow to 3-4+ feet tall.