You Can Dig It

The hard lessons learned from 'patriotic planters'

By Jim Janke | Jan 04, 2017
Photo by: Jim Janke

Last year, I replaced the window boxes on our deck railing with a larger size, and was looking for something to do with the old ones. So I grew red, white and blue annuals to attempt to create some “patriotic” containers for our garden.

I chose species I had previously started from seeds with good results — red impatiens, white alyssum and blue lobelia.

Seeds were scattered on top of a peat-based seed-starting mix the seeding flats covered with clear plastic and placed in a tray with a half inch of water.  Germination was good for all three. After good second leaves appeared, they were transplanted to six-packs and grown under fluorescent lights at cool room temperatures.

Lobelias and alyssums were fed every week or so with a half-strength soluble fertilizer; the impatiens seedlings were not fertilized. I

n late April the plants were hardened off by setting them outside for increasing lengths of time over a two week period, then planted in some old window boxes after the chance of frost has passed. The containers received morning and mid-day sun, but shade in the late afternoon.

They were fed monthly with a slow-release fertilizer. Watering chores were minimized because the containers were “sub-irrigated planters” with water reservoirs.


Lessons Learned

— Seeding dates on the seed packets were way off for two of these plants. Starting lobelia Feb. 1 was too early, as by the middle of March the plants were 6- to 8-inches tall and blooming profusely inside. To keep them alive until May, I had to cut them back by more than half. Alyssums were seeded March 1, but grew very slowly; a month earlier would have been better.

— Lobelia bloomed well, but the flowers were small and overwhelmed by the larger impatiens blooms.

— The impatiens variety I chose didn’t like morning sun, resulting in less than perfect flowers, although the plants bloomed continuously all summer.

— All the alyssums died within a couple of weeks after transplanting into the window boxes. They were replaced with white vincas from a local nursery.

— Planting two of each variety in each container resulted in over-crowding. The higher plant density made it difficult to keep up with watering chores, even with self-watering planters

So while my experiment produced acceptable containers, the results were not what I had hoped. If I do this again I’ll probably just buy plants locally instead of raising them from seeds.

The cost would be about the same, yet I’ll know better what the plants will look like compared to just looking at seed catalog pictures.

And I’ll use plants that are close to the same height and have roughly the same flower size, so one variety doesn’t dominate the others.

Jim Janke is an Extension Master Gardener wolunteer in Haywood County. For more information call the Haywood County Extension Center at 456-3575. © 2017 NC State University.