In our experience, yes and no. We are in our third year of growing cut flowers and we’ve tried planting cool flowers each of the past two autumns. The concept is to plant in September hardy annuals that can survive our zone 6b winters, which allows these flowers to germinate and grow some before the first frost – typically in mid- to late-October where we farm – when they then go dormant for the winter and “wake up” in spring to continue growing. When it works, planting cool annuals this way can give growers a head start in spring, allowing them to get flowers to market much sooner than otherwise would be possible.

Does it Work?

We’ve had mixed success with planting cool flowers in the fall. Last year, we planted nine varieties of cool flowers, and some did well, some survived but didn’t thrive, some died and some were a mixed bag.
Did well both years:

  • Sweet William
  • Nigella (Love in a Mist)
  • Bachelor Buttons (Cornflower)
  • Bupleurum
  • Larkspur
  • Orlaya (this was our first year growing it)

Did poorly or inconsistently:

  • Stock – most of it froze to death, but we replanted in the spring
  • Snapdragons – did okay, but didn’t grow very tall
  • Iceland Poppies – did well the first year and very poorly the second
  • Bells of Ireland – grew well the first year, but we weren’t fond of them and didn’t plant them the second year

Larkspur vs Stock

We have decided to not grow larkspur again because although it grows well, the petals tend to shed and make a mess. We much prefer stock, which is similar to larkspur, is more attractive, and has a wonderful aroma.

Row Cover and Low Tunnels

We use 0.55oz Agfabric plant covers (“row cover”) whenever we sow seeds, including cool flowers. This keeps birds and other animals out of the seed, but it also offers some minimal freeze protection. Note: this white fabric, which comes in 6’ x 100’ rolls, is different (thinner) than plant covers intended to serve as winter frost blankets. It allows 85% light transmission, and is air and water permeable.

When we first sow the seeds, we lay the row cover flat on the ground over the bed and secure it with rocks and bricks. Once seedlings appear, we either remove it entirely or make a low tunnel with it by stretching it over Pex hoops.

We also use 6-mil, UV-resistant, clear plastic film to make low tunnels that can help protect plants from cold and wind via solar gain. It’s amazing how much a thin sheet of plastic can help keep plants alive in cold weather. Water the plants can be a challenge, though, since the plastic sheds rain.

Now is the Time

Mid-September is the perfect time to plant cool flowers and we’ll be doing that over the next week.