How To Grow Phlox Flowers From Seed

Sweet Phlox, phlox drummondii, is such a lovely flower to have in the garden. Taller varieties make a lovely cut flower, where as shorter varieties make a great bedding flower and grow well in pots. A hardy annual that doesn't need a lot of care once established.
Loads of flowers on branched stems with the blooms that change colour when opening. My favourite would have to be Phlox cherry caramel, coffee tones with a vintage cherry eye.
Germination Tips
  • I would recommend raising seedlings. 
  • Sow seeds 4-6 weeks prior to the last frost, directly into their final containers or seed trays. Cover the seeds with soil, making sure they are completely covered to ensure darkness for germination. Another option is to cover the tray with something like newspaper until germination has occurred. 
  • Germination will occur between 5-21 days at 16-18 degrees.
Planting Tips
  • Once the seedling have reached around 6 weeks of growth and have two sets of leaves, it is time to harden the seedlings off. Do this by putting the seedling outside for a few hours on the first day, gradually working up to a full day to prevent any transplant shock. Take care when removing the seedlings from the pots, as phlox very much dislike their roots being disturbed!
  • Choose a full sun position to plant the seedlings, taller varieties will grow to around 50cm high, these can be staked which will help create longer, straighter stems.
  • Space each seedling 15-25cm apart.

Tip, pinch out the first flower for longer stems.

Harvesting Tips
  • Harvest when around 50% of the flowers have opened.
  • Phlox flowers will last 7-10 days in a vase.