Overwinter Flower Production in Tunnels
Many hardy annual flowers can be grown in unheated tunnels overwinter for spring harvest. This is a great way to extend the growing season, and for early blooms--ideal for Mother’s day sales in May!
A couple of things to keep in mind for overwintering flowers are day length and temperature. Day length can be accounted for by variety selection and transplant dates; a good rule of thumb is to transplant three to four weeks prior to day length dropping below 10 hours per day. Temperature control can be regulated by transplant date, as well as row cover usage.
If growing in unheated tunnels in areas with consistent temperatures below freezing, row cover will be needed. In more temperate winter climates row cover can be used when these same conditions occur. Planting into plastic mulched beds can also assist in keeping the soil warm throughout these winter months. Be sure to maintain soil moisture with drip irrigation.
Some hardy annuals to transplant for overwinter tunnel growing include: snapdragons, Ammi, Digitalis, Daucus, Dianthus, Bells of Ireland, Icelandic poppies, and Scabiosa. A few that can do well direct seeded include Nigella, bachelor button, and Bupleurum.
Many tunnel grown flowers will be bushier than when they are grown outside, and may need additional support.
Shown here are a few of our favorite varieties to try for overwinter tunnel growing!