YOU MIGHT BE WONDERING WHEN, exactly, to winter-sow your perennials, annuals, herbs and veggies outdoors. The easiest answer is “now.” However, to save work later on, it pays to plant certain seeds ahead of others. The following schedule has worked well for me:
Perennials and Hardy Annuals. As a rule, if a plant is hardy in your zone, you can plant its seed any time in winter, regardless of the temperature outside. Sprouting will occur when warmth arrives, normally in spring. However, the seed can also sprout during some freak warm spell between weeks of frigid conditions. This is not a problem for perennials and hardy annuals. They simply yawn in the face of frost.
Tender Annuals. You can plant these early, too, with one important caveat: Should sprouting occur during a warm day (and remember, it’s even warmer inside the milk-jug greenhouse), you’ll have to throw a blanket over the container at night. For such seedlings are easily killed by frost. That’s why they’re called “tender.” Consequently, to avoid the covering-work, it pays to delay sowing the tender annuals until March or April.
Last year, in my own, zone 5-b garden, I planted perennials, annuals, herbs and vegetables using the following time-table. All of the seeds sprouted and survived (except the Delphiniums, probably because the seeds were old).
January through February:
Flowering Perennials & Hardy Annuals
Digitalis purpurea (Wild Foxglove)
Oenothera speciosa (Evening Primrose)
Consolida (Larkspur) ‘Galilee Blue Double’
Aquilegia (Columbine) ‘Alpina’ blue
Aconitum carmichaelii (Monkshood)
Delphinium grandiflorum ‘Blue Mirror’
Nepeta ‘Pink Dreams’ pink
Oenothera lamarkiana yellow
Alcea (Hollyhock) ‘Camois Rose’ rosy-pink
Alcea ‘Apple Blossom’ pale-pink
Berlandiera ‘Chocolate Flower’ yellow, fragrant
Campanula (Bellflower) ‘Champion Pink’
Campanula latifolia ‘Brantwood’ purple
Lathyrus odoratus (Sweet Pea) fragrant
Nicotiana ‘Fragrant Cloud’ and ‘Purple Perfume’ (I also sowed these indoors, under lights; both grew with equal exuberance)
Platycodon (Balloon Flower) ‘Sentimental Blue’ (pictured above)
Lupinus (Lupine), ‘Russell Hybrids Mix’
Centaurea cyanus (Bachelor Buttons) common blue variety
Vegetables & Herbs
Thymus serpyllum (Creeping Thyme)
Salvia (common sage)
Tomatoes (I also grew tomatoes indoors under lights; I can tell you the winter-sown plants not only survived a few below-freezing nights without covering — they were stronger than the light-garden subjects, too)
Again, this planting schedule is based on my own, zone 5-b climate. If you live in a milder zone you can winter-sow your seeds much earlier than me. I know a Texan who winter-sows his tomatoes in December.
In any event, let me know if you have any questions concerning the timing of your own winter-sowing projects. Be sure to include, in your comment, which zone you are in. Meanwhile, have fun planting your garden at the “wrong” time of the year!
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Winter-Sowing 101: The Basics
How to Turn a Milk Jug into a Greenhouse
My Favorite Seed-Suppliers…& Yours (2012 Edition)
Perennials Which Require Cold Stratification
A Seed I’d Winter-Sow: The Chocolate Flower (Berlandiera lyrata)
A Seed I’d Winter-Sow: The Bachelor’s Button (Centaurea cyanus)
Seeds to Winter-Sow: Platycodon ‘Sentimental Blue’