Winter Flower Seeds: Best Flowers to Winter Sow and How to Do It

The best winter flower seeds are the hardy annuals and perennials that can be sown outdoors in the middle of winter, in simple vented containers that work like miniature greenhouses. Instead of starting seeds on a windowsill, you sow them in jugs, tubs or bags, set the containers outside in the cold, and let the weather decide when each seed wakes up. The result is earlier spring flowers from tougher plants, with no grow lights, no heat mats and no hardening-off. This guide explains how winter sowing works, the exact container method step by step, the flowers that suit it best, and when to sow each one. It also cross-checks the winter flower catalogue this page originally carried, because most of the flowers in that catalogue turn out to be textbook winter-sowing choices.

What is winter sowing, and why does it work?

Winter sowing means sowing hardy flower seeds in small covered containers placed outdoors during winter, so the seeds experience real cold and germinate naturally as conditions improve. The containers act as mini-greenhouses: they shelter the seed from birds and washing rain while still exposing it to the freeze and thaw cycles it would meet in open ground. That cold treatment, called stratification, is exactly what many hardy seeds need before they will sprout. Because the seedlings emerge already living outdoors, they are stocky and hardy from day one, and they bloom earlier in spring than plants started indoors and transplanted out later.

• No grow lights, heat mats or indoor seed trays are needed at any stage.
• Seedlings never need hardening off, because they germinate outside.
• Nature handles the timing: each variety sprouts when the weather suits it.
• The freeze–thaw cycle breaks dormancy the way it does for self-sown seed in the wild.
• Plants come up earlier and hardier than indoor-started equivalents.

How to winter sow flower seeds, step by step

The winter sowing method has ten simple steps, and the most important one is the first: wait until nights are properly cold. If you sow while the weather is still mild, seeds may germinate early and then be killed by the next freeze. Once nights are cold enough to keep seed dormant, prepare vented containers, sow sparsely, seal them up, and put them outside. From then on the containers mostly look after themselves. Do not open them during a freeze or an early-spring thaw, however tempting it is to peek, and only bring them indoors if the wind turns severe enough to throw them around the garden.

1. Wait until nights are cold enough to keep the seeds dormant.
2. Choose a translucent container: a milk jug, a clear plastic tub with a lid, or a gallon zip bag.
3. Cut drainage holes in the bottom — five or six in a milk jug — and slits or vents in the top so rain can enter and excess water escape.
4. Add 3–4 inches of potting mix (a few inches in a shallower tub), and moisten it so it is damp but not soaked.
5. Sow the seeds at their normal depth and keep the sowing sparse; one guide suggests no more than three or four seeds per container.
6. Seal a cut milk jug shut with duct tape; close tub lids, and zip bags almost shut, leaving a small vent opening.
7. Set the containers outdoors in a sheltered spot exposed to rain and snow — milk jugs in the sun, other containers in part shade.
8. Leave everything closed through freezes, and do not open a container in freezing weather or a sudden thaw.
9. As spring warms up, open the lids on warm days for ventilation and close them again before nightfall.
10. Once all danger of frost has passed, remove the tops for good and transplant the seedlings when they have two or three sets of true leaves.

Milk jug, tub or zip bag? Choosing a container

Any clear or translucent container that holds a few inches of mix and can be vented will work for winter sowing, and the three common options differ mainly in soil depth and how soon the seedlings come out. The milk jug is the classic choice and gives seedlings the most room. Clear tubs are easier to fill but shallower, so their seedlings are transplanted sooner. Gallon zip bags take up almost no space and lie flat across a raised bed. Whichever you choose, avoid bio-pots and seed trays, which dry out and break down outdoors; sturdy reusable containers are the reliable option.

The best winter flower seeds to sow

The flowers that winter sow best are hardy annuals, biennials and perennials whose seed either needs a period of cold or is completely unbothered by it. The twelve flowers in the table below appear again and again across winter-sowing lists from seed companies and experienced growers, which makes them the safest place to start. Most are sown in winter or early spring, as soon as the soil can be worked, but a few have their own timing: foxglove and forget-me-not go in a season early, in late summer or early fall, while snapdragons are counted back from the last frost date. Perennials such as delphinium and yarrow sit at the other extreme and will not germinate well without weeks of genuine cold.

Beyond the table, the same lists regularly include columbine, coneflower (echinacea), lupine, alyssum, dianthus and sweet William, strawflower, verbena, cosmos, black-eyed Susan and marigold, so there is plenty of choice once the basic method is familiar. Two cautions are worth keeping in mind. Lupine seed is sown very shallowly, only about 1/8 inch deep, and grows into a plant 2–3 feet tall, while petunia goes to the opposite extreme: its seed needs light to germinate and should be covered with nothing more than a sprinkling of soil. And leave zinnias out of the winter containers altogether — they are the exception that proves the rule, sown later in spring because they need warmth, after which they bloom quickly.

A winter sowing calendar: when each job happens

Winter sowing spreads a few small jobs across the cold season rather than demanding one big sowing day, and the calendar below puts them in order. The two sowings gardeners most often miss are the earliest ones: foxglove and forget-me-not are actually sown in late summer or early fall, and the long-chill perennials such as delphinium need to be outside by early winter to clock up their 60–90 days of cold. Everything else falls into place from there — the main wave of annuals goes in during winter, pansies and sweet peas wait for late winter, and the spring jobs are simply opening, ventilating and finally transplanting what the weather has raised for you.

Spring care and transplanting

Spring care for winter-sown containers is mostly a matter of ventilation and patience, not feeding or fussing. As the weather warms, open the lids on warm days so seedlings get fresh air and do not overheat, then close them again before nightfall while nights are still cold. Resist opening containers during a late freeze or a sudden thaw, and do not panic about hard weather in general: one winter-sowing grower recorded several days at −9°F with containers half-buried in snow, followed by nearly 100% germination in spring. When the danger of frost has passed, take the tops off completely. Transplant each seedling into the garden once it carries two or three sets of true leaves; because the plants have lived outdoors all along, they go into beds and borders without any hardening-off period at all.

The winter catalogue this page started with, cross-checked

This page began as a five-page winter flowers catalogue for 2023, listing seed packets by name with a photograph of each flower, and that catalogue is preserved in full in the images on this page. Cross-checking its flower list against the winter-sowing recommendations above produces a reassuring result: most of the catalogue’s headline flowers are also recommended winter-sowing flowers. Its snapdragon (listed as antirrhinum), calendula, cosmos, pansy, poppy, sweet pea, verbena, dianthus, larkspur, cornflower and marigold all appear on the specialists’ winter lists, along with its lupine, aster, salvia, petunia, strawflower (helichrysum) and sweet alyssum. In other words, a seed order placed from that catalogue is already most of the way to a winter-sowing plan.

The catalogue’s remaining pages, below, round out the list with dahlia, gazania, stock, primula, ranunculus and Swiss chard alongside the African daisy (arctotis) from its first page. A few names are spelled loosely in the original printing — “Dehlia” for dahlia, “Patunia” for petunia, “Philox” for phlox — but every flower is easy to recognise from its photograph. Gardeners building a winter seed order can treat the catalogue as a shopping list of candidates, then use the sowing table and calendar above to give each packet the timing it actually needs.

Winter flower seeds: frequently asked questions

What flower seeds can I grow in winter?

You can grow hardy annuals, biennials and perennials in winter, including pansy, calendula, cornflower, larkspur, delphinium, snapdragon, sweet pea, poppy, foxglove, forget-me-not, nigella, yarrow, columbine, coneflower, lupine, alyssum, verbena, cosmos and black-eyed Susan. Tender flowers are the exception: zinnias, for example, wait until spring because they need warmth to thrive.

What flowers can I start from seed right now?

That depends on where winter has reached in your garden. In deep winter, sow the long-chill perennials such as delphinium and yarrow, and keep containers shut through freezes. In late winter, add pansies, pulmonaria, ornamental kale and sweet peas. Snapdragons are timed by counting back 8–10 weeks from your last frost date.

What are the best seeds for winter flowers?

The most forgiving choices are calendula, cornflower, pansy, larkspur, sweet pea and poppy, which appear on almost every winter-sowing list. Calendula flowers about 45–60 days after germinating, cornflower reaches 2–3 feet, and sweet peas bloom for 6–8 weeks once they climb their trellis, so the beginner’s shortlist also performs well.

What flowers bloom all winter long?

Winter-sown flowers do not bloom through winter itself, because the seed rests dormant in the cold and germinates only when conditions suit it. The payoff comes at the other end: earlier spring blooms from hardier plants than indoor starting produces. The winter weeks are for sowing and stratification, not for flowers.

Do I need grow lights or a heat mat?

No. Winter sowing needs no grow lights, heat mats or indoor trays at all. The vented container outdoors is the whole system — it shelters the seed, admits rain and snow, and exposes the seed to the natural freeze–thaw cycles that trigger germination right on time.

When do I transplant winter-sown seedlings?

Transplant winter-sown seedlings when each one has two or three sets of true leaves. First remove the container tops for good once all danger of frost has passed. Because the seedlings have grown outdoors from the start, they move straight into the garden with no hardening-off.