Flower Seeds to Plant in fall, winter, or early spring
Some flowers grow better in cooler weather.
If those same flowers were planted when the days are longer and warmer, like when you would plant sunflowers and zinnias, they would not get as tall or full as they would if they were grown in cooler weather and shorter days. And they usually wouldn’t flower as well or for as long. Or they may not even germinate.They’d grow only as much as necessary to be able to throw out at least a few seeds for next year. After all, that is what flowers are all about.
I’m in USDA Zone 8. We have a nice long growing season where it’s important to plant the cool weather flowers quite early. I get most of my cool weather flower seeds in the soil in fall or in January to mid-February. It does snow here, and freezes, but the soil rarely freezes.
If you’re in a colder zone the seedlings can freeze. Or the soil can be covered with snow for a long time making it hard to plant.
If you live in the colder zones your time window to plant is shorter. The cool weather flowers go in just before the warm season ones. And they’ll bloom as your warm weather flowers are gearing up. You most likely have a window where you can mix the cool weather flowers with the warm ones in bouquets, which is nice.
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Is there an advantage to planting early?
Yes! These seeds can sit in soil, and when conditions are right, they’ll germinate. Their first little root, the radical (really), grows down into the soil and starts working on growing and developing its feeder roots. That gives it a head start for the plant to grow well in the spring. Unless the ground goes into a deep freeze.
Soil freezes when the soil temperature goes down to 20 °F. That’s when tender young roots can die. If that describes what you face, you’ll be planting your early season seeds in spring…just before the warm season flowers, like sunflowers. So it’s best to know your zone
How to know your zone?
The USDA Zones are plant hardiness zones which tell you what plants won’t freeze in your winters. It shows what the average winter low temperatures are for your area. You can find your USDA Zone with this map. It helps you know what will or will not grow where you live.
While the zone only tells you the lowest average winter temperatures where you are, this number will help you determine what you can and cannot grow when you’re reading plant labels at a nursery or in plant catalogs.
Please note that plant hardiness applies to perennial plants only because they live through the winter. Annual plants die at the end of the season anyway, so you’ll have to know your climate. You would know if your ground is frozen almost all winter till early May or, like in my area, if it rarely freezes.
A zone with a lower number tells not only the lowest average temperatures but also indicates the severity of the winter, and whether snow will cover the ground, and for how long through the winter it will be present, and whether the soil may freeze.
There is always a Master Gardeners group near where you live that has a handle on the facts of the seasons and zones and sub-zones for your area if you’re in the US.
Which flowers are best planted in fall, or winter...or right after the thaw?
The cool weather flowers that you want to plant early before, during, or right after winter include Ammi, Bachelors buttons, Breadseed Poppies, Calendula, Larkspur, and Nigella. When planted early they’ll give you the best flower harvest and some will have cool pods to use in dried florals. These are all annuals (link).
By early, that can mean fall for people in Zone 8 or April or May for those in Zone 5. And don’t be fooled by a prolonged warm spell. Our weather is getting less predictable these days and late freezes can happen. Though, these plants can weather a light freeze.
Plants that self-sow, that is, they drop their seeds will overwinter and come up voluntarily the next spring, offer the perfect clue that you can plant those in fall, or February if there’s no snow on the ground. They can survive the winters. All of the above mentioned seeds handle this well in my area. This is a strong clue that they can overwinter where you are.
And a big clue is on the seed packet: “Sow as soon as the soil can be worked”. For those in warmer zones, 7 and up, you’re most likely very safe planting in fall or winter. Check with the Master Gardeners in your area if you’re unsure.
If your USDA zone allows it...
If you can safely plant the cool weather growers in fall or in winter, you’ll get the best from your plants. If you’re in a colder zone, you can plant after the thaw and you’ll benefit from an overlap season that has both cool growers and warm ones at the same time. And you’ll be planting “as soon as the soil can be worked.”
Agrostemma, Ammi, bachelor’s buttons, breadseed poppies, Calendula, larkspur, and Nigella will all grow and bloom as many of your spring flowering bulbs are blooming, giving you lots of early flowers and cool pods, too.