Jule Romans has been gardening with native wildflowers for over 15 years. She loves to share knowledge about her favorite native plants.
Yes, you can plant flowers in the winter without any special tools or expertise! Although it might seem completely unbelievable, hardy perennial flowers will germinate and grow nicely well before the last frost. All it takes is knowledge of some basic principles.
The Appeal of Winter Sowing Flower Seeds
Planting flowers in the winter months may seem impossible. It is actually quite simple and rewarding. Almost any type of container can be adapted to plant flowers in the winter. It is surprising how easy it is to use a milk jug to create a small outdoor mini-greenhouse.
Winter sowing will not take up any room indoors. It will not require the building of any structures. It does not cost a great deal money, either. Best of all, it is incredibly easy to do, and this article will show you how.
Planting Flowers in Winter Is Not a New Idea
The process to plant and grow flowers in the winter months is actually quite an old one. Many gardeners who love flowers have used some of the key elements of winter sowing for years. Many experienced gardeners understand that providing plants with adequate cover can protect them throughout the winter months.
It is possible to sow certain flower seeds in their own individual mini-greenhouses. The seeds will germinate and sprout inside the containers very early in the season. Seedlings will continue to grow safely, even through early spring frosts and harsh weather. When the ground warms in spring, the plants are healthy and strong enough to be transplanted in the garden. These plants tend to be more hardy and vigorous than other garden flowers.
Sowing Wildflower and Perennial Seeds in Winter
Cold temperatures are not a threat to most garden perennials. As any tour of a winter garden will reveal, perennial plants tend to remain green under snow as long as they are close to the ground or in a protected location.
It is also a fact that certain perennial flower seeds actually depend on the freeze and thaw cycle in order to break their hard coats and germinate properly. Their seeds must be subjected to several weeks or months of freezing temperatures, or they will not sprout. Two very popular garden plants that fit in this category are Purple Coneflowers and Black Eyed Susans. These flowers also have the added benefit of being prolific spreaders with long lasting blooms.
Choose Hardy, Native Perennials
Choose a hardy perennial, preferably one that is native to your area. Perennial flowers, especially those that are native to North America, are not at all afraid of the cold. Many varieties actually need to have their seeds exposed to freezing temperatures in order to germinate and sprout. Many of these are already garden favorites. Black Eyed Susans, Purple Coneflowers, and Indian Blanket are examples of flowers that gardeners can plant in the winter. These three are very good choices for beginners.
The Principles of Winter Sowing
In essence, planting flower seeds successfully in winter requires only three things:
- Adequate cover
- Proper ventilation
- Good drainage
Given these three conditions, perennials can be started from seed anytime after mid-December. The procedure can be completed using everyday materials found around the home.
Make Tiny Greenhouses With Milk Jugs
One very common strategy for winter sowing is to use a one-gallon plastic milk jug.
A clean milk jug, minus its cap, is cut in half. The opening left by the missing cap will provide the proper ventilation. After filling the bottom half with good potting soil, the gardener then adds seeds and waters thoroughly. The top half of the jug is replaced and secured with tape. Then, all that remains is to place the container outside and let nature do the rest.
The result is early germination inside a protected individual greenhouse that shelters tender seedlings just the right amount to keep them growing with increasing strength.
There are many, many variations on the basic idea. Container choices can range from clear-topped cake boxes to paper cups topped with plastic bags. Moisture control potting soil or soilless mixes can be used.
Planting Flowers Makes Winter More Enjoyable
Perennials, grasses, herbs, lilies and re-seeding annuals all seem to grow well with winter sowing. One of the best things about winter sowing is that it is especially successful with native plants, which makes it very good for the environment.
It is possible to grow healthy, strong flowers from seed, even in the dead of winter. Once begun, the process is addictive. Soon, instead of dreading winter, you may find that you welcome it as an opportunity to plant more flowers.
Plant Flower Seeds in Winter Using a Milk Jug
Here's how to plant flower seeds in the wintertime using primarily just a milk jug.
1. Select the correct variety of seeds.
Choose a hardy perennial, preferably one that is considered “native.” Perennial flowers, especially those that are native to North America, are not at all afraid of the cold. Many varieties actually need to have their seeds exposed to freezing temperatures in order to germinate and sprout. Many of these are already garden favorites. Black Eyed Susans, Purple Coneflowers, and Indian Blanket are examples of flowers that gardeners can plant in the winter. These three are very good choices for beginners.
2. Prepare the container.
Wash and rinse the plastic milk jug thoroughly. Plenty of warm water should do the trick. Very mild soap is acceptable as well. If desired, allow the container to air dry for few hours or overnight.
3. Remove the plastic cap from the milk jug.
It will not be needed. The opening left by removing the cap will provide ventilation for the growing plants. It will also allow rain and snow to come in to the container to provide water. In addition, this hole will provide access for hand-watering of plants as needed.
4. Cut the milk jug the middle.
Cut just under the handle of the jug. Begin the cut next to the handle, about a half inch below it. Using a sharp knife or scissors, slit the plastic almost all the way around the circumference of the jug. Stop the cut just before reaching the other edge of the handle. This will make the milk jug “open up” along the cut, without cutting it entirely in two. Don’t worry if it gets cut all the way around. That’s what the tape is for. It’s just easier if the two halves stay attached.
5. Create drainage holes.
Create drainage in the bottom of the container. Using an awl, sharp knife, or scissors, cut several holes in the bottom of the milk jug. These holes will allow the soil to drain properly. The number of holes needed depends upon their size. Seven to ten small round holes are adequate. Slits or “X” cuts will need to be in a higher number. It is not a precise or exact process, nor does it need to be. As long as there is some drainage, the container will function well. Holes can be added, or covered with tape as needed later on.
6. Fill the bottom half of the container with soil.
Pull back the top half of the container, and fill the bottom half with good quality potting soil. Any decent potting soil will do, although some gardeners have strong preferences for certain brands or mixes. For the first time, though, simply make sure the soil is healthy and clean. Shake or pat the container to level the soil, but do not pack it in forcefully.
7. Sprinkle seeds on top of the soil.
Open the seed packet and sprinkle the seeds fairly evenly across the surface of the dry soil. Pat seeds down into the soil, pressing firmly over the entire soil surface. Some seeds will still show at the surface of the soil. Press individual seeds into the surface, but do not poke holes or bury the seeds deeply. These types of flower seeds need to be sown fairly close to the surface of the soil. A good rule of thumb is to bury a seed only half as deep the size of the seed itself. For most perennial flower seeds, this is less than 1/8inch.
8. Water the soil and seeds.
The easiest and cleanest way is to set the container in a pan of water for an hour or two. The soil will absorb water through the drainage holes. Check occasionally, and when the soil is saturated, lift the container out and place it in the sink or in another empty pan. Containers can also be watered from the top of the soil, but this takes more time and care must be taken not to disturb the seeds. Either way, is sure the soil is well saturated with water. Some seeds will float to the top of the soil.
9. Check and cover the seeds.
Press the seeds back down firmly into the wet soil. Sprinkle a small amount of additional potting soil over the seeds to cover them. Press the dry soil down gently. If this is done correctly, the dry soil will soon become saturated.
10. Label the container and close the top.
Place a wooden or plastic plant marker in the soil inside the container. Or, use a permanent marker to write the name of the plant directly on the milk jug. Close the container. Secure the top to the bottom with tape, if desired. Or, tuck the top portion into the bottom half of the container. Tape is recommended if the container is to be placed in a windy location.
11. Place the container outside.
Place the entire container outside in a relatively protected location. Leave it there until spring. The seeds will sprout as temperatures inside the container warm up- even if the container is covered in snow. The plants will be ready to be transplanted into the flowerbeds as soon at the have a full set of true leaves. Seedling will grow well and can remain inside the container for several weeks to several months. The top will allow the seeds and seedlings inside to receive adequate moisture and ventilation.
Watch, Wait, and Enjoy
These are the steps to take to plant flowers in the winter. After the containers have been placed outside, there is very little to worry about until spring. These types of flowers can take care of themselves. Choose the right seeds, prepare containers correctly, provide adequate conditions and even winter can be a great time to plant flowers.
Davidoff, Trudi. 2015-2021. Wintersown: We'll Help You Grow. "How to Winter Sow." <wintersown.org>
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Jule Romans