Flower Farming

overwintered flowers in high tunnel

Choosing Flower Crops to Overwinter: Results from Our Trials

Snapdragons in a high tunnel on the Johnny's Research Farm.

By Hillary Alger, Flower Product Manager, and Joy Longfellow, Flower Trial Technician, Johnny's Selected Seeds

We have conducted extensive multi-year overwinter flower trials in unheated high tunnels at our Zone 5a Research Farm in Central Maine. Here is a compendium of our trial results by crop, including our top 6 crops for beginners and a comprehensive review of all crops we have trialed.

Top 6 Flowers for Overwintering in Tunnels

If you are new to overwintering, we recommend starting with one or more of our Top 6 Flowers for Overwintering in Tunnels:

  1. Sweet Pea
  2. Snapdragon
  3. Digitalis
  4. Dianthus
  5. Pansy/Viola
  6. Icelandic Poppy

These 6 cut-flower crops have consistently performed well in our overwinter trials. They have proven the most reliable for survivability, high stem quality, productivity, and earliness, compared to field plantings. If you are new to overwintering flowers, refer to our Introduction to Overwintering Flowers for an overview of our overwintering methodology.

Over 30 Flower Crops to Overwinter

Overwinter Flower Trials Results by Crop Download our Overwinter Flower Trials • Results by Crop for details on over 30 flower crops we overwinter here on our Zone 5a Research Farm in Maine.

As you look to expand beyond our top 6, start your crop exploration with a review of our Overwinter Flower Trials • Results by Crop, a downloadable spreadsheet that you can save to your system and put to work for your own planning and recordkeeping purposes. The workbook details over 30 flower crops we overwinter in unheated tunnels here on our Northern-Tier Farm in Maine and it includes a wealth of information on:

  • Seeding and transplanting dates
  • Survival rates
  • Bloom window
  • Harvest window
  • Yield
  • Recommended varieties
  • Pros, cons, and growing notes

Extensive note-taking on the results of the winter tunnel flower production starts early and keeps going, ending one year's cycle while beginning the next. Once you are past the summer solstice, it's already time to plan for the upcoming overwinter flower production, and in swift progression it's time to start seeds, prep the tunnel, then transplant seedlings into the tunnel. Making time for good recordkeeping pays off by helping you assess and weigh economic considerations in relation to your production system and markets, make sound choices, and achieve optimal results.

Performance Recap: Flower Crops from Our Trials

bucket of harvest overwintered flowers
Overwintered flowers at our Research Farm.

Here is a detailed recap of our best-performers in our overwinter flower trials. Click on each crop to watch a video about overwintering the crop and see it in bloom in the high tunnel.

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