Late Autumn Seed-Sowing for Spring Blooms! Tips, guidelines, and steps for success

As the weather begins to cool down and we enter the first few days of fall, it may feel like the garden is ready to bed down and go to sleep until next spring.

(same!)

But this seemingly sleepy season is actually a key growing time of the year. In the fall and early winter, we have a period of time before the ground fully freezes, which contains ample opportunity to get our fall plantings squared away. This is a great time to get your fall trees and perennials in the ground, and the perfect opportunity to plant your bulbs, cold stratification- desiring flower seeds, and wildflower mixes for early spring blooms! 

Below is a guide for sowing annual, perennial, and wildflower seed mixes directly into your garden this fall for early spring blooms. We’ll discuss cold stratification, why it is necessary in order for some seed species to germinate, and how, sometimes, nature just does it best. We’ll look at how to select seed varieties to sow in your garden including what varieties Painters Greenhouse has to offer! And last, a step-by-step how-to guide on sowing your flower seeds; when, where, how, and why to sow seeds in the fall. 

If you’ve spent enough time around plants (or gardeners), you’ve probably come across the term stratification or stratifying seeds. Many annual and perennial seeds are in a state of dormancy to prevent germination until the conditions are just right. Stratification is the natural or artificial process in which variations in temperature, moisture, and light break a seed’s dormancy. After which, the seed is ready to germinate if favorable conditions are met. 

There are two main ways to stratify seeds: one is “artificial,” i.e., mimicking cold, wet conditions in your refrigerator in a moist seed starting medium. The other is letting the elements take the wheel, and directly sowing your cold-stratification desiring seeds outdoors. In this post, we’ll be looking at the second method: cold/wet stratification via nature. We’ll guide you in sowing annual, perennial, and flower seed mixes outdoors this fall, so we can let Mother Nature do her thing to bring you early blooming flowers in the spring! 

What should you choose? And how does one know which seeds need to be stratified?

Checking out your seed packets is a great place to start. Typically, most seed packets will say in their seeding instructions if the seeds within benefit from stratification, along with information on planting depth and time of year to sow. 

We have a great selection of seed packets from local business Sow True Seeds currently in stock that benefit from cold stratification (see photo below). 

Some annual and perennial seed varieties that we carry that benefit from cold, wet stratification are Butterfly Milkweed Asclepias tuberosa, Bee Balm 'Lemon Mint' Monarda citriodora, Lanceleaf Coreopsis Coreopsis tinctoria, Dianthus 'Sweet William' Dianthus barbatus, Purple Coneflower Echinacea purpurea, Lupine 'Russell Mix' Lupinus polyphyllus, Rudbeckia 'Gloriosa Daisy' Rudbeckia hirta, and Oriental Poppy Papaver orientale. 

Note: Sow True Seeds also has a great list and an excellent blog on their website, which answers specific questions about the varieties they carry. If you find yourself having additional questions, their website is a great place to do further research. 

Some other varieties which may readily self-sow and stratify in your gardens are columbines, snapdragons, marigolds, milkweed, echinacea, goldenrod, and Joe Pye weed, to name just a few. If you’ve purchased nursery-grown annuals and perennials and planted them in your gardens this year, you may be surprised to see that they have broadcasted seed this fall and sown little volunteers you’ll find next spring (or the spring after!)

If you can't choose just one, seed mixes are great options for buffing up spaces between planted perennials in your garden or starting wildflower meadow patches in your yard. Seed mixes can serve a variety of purposes beyond simply aesthetic reasons. They can be used as pollinator and bird food, habitat, erosion control, native plant propagation, and more. Some of the seeds mentioned above and in the mixes at Painters have species that will poke their heads up next spring, and others may not appear until the fall or spring after. Adding seeds to the garden is a great way to sow for the future, and it can be really fun to see what pops up in following years. 

We currently offer the following mixes in our checkout building: “Bee Feed”, “Monarch Butterfly”, “Southeast Native Mix”, and “Hummingbird, Butterfly, Songbird”. 

When I first started my garden two years ago, I planted a variety of perennials and filled in the spaces with seed mixes and a hodgepodge of random annual and perennial seeds. Being the chaos gardener that I am, I wrote nothing down and am delightedly surprised with what has come up each year. I’ll find a monarda that I don’t remember planting, and in the fall, I have a bank of asters that will pop up, along with tons of little celosia starts that self-seeded from their mother plants the previous year. 

A close-up of an area of my garden where I scattered a wildflower seed mix to fill in gaps. The poppy, allysum, phlox and coreopsis are all from seed.

If you’re okay with some surprises, you can always sow and go, but if you’d like a little more structure to your process, labeling, taking notes, or starting seeds in a “nursery” patch in your yard and then transplanting them to your main garden may make the process a little more organized. 

Now that you have your seeds picked out that you want to try to stratify outdoors this winter, what’s next?

The best time to fall sow cool-season seeds is after your first hard frost and before the ground completely freezes. You could even time your fall bulb planting with your seed sowing!

Check your plant hardiness zone

Check your estimated first frost

Where should you sow your seeds?

Your site can be a recently cleared patch of earth that you want to fill with some spring beauty, it could be an area that was disturbed by the hurricane last year that you would like to remediate and start building soil back up, it could be little areas between shrubs or other plantings in your gardens, it’s up to you and your seeds! Key things to look for when choosing a site are sunlight, soil composition, and drainage. Most plants appreciate a sunny spot with sharp-draining soil, but always double-check the preferences of seeds you're planting for the best success. 

How should you prepare your site?

Rake or till the area you’d like to sow your seeds. You can use this time as an opportunity to add a little mushroom compost or soil mix of your choosing (especially if you have a lot of clay or fill dirt like I do), but you don't have to! You can use what’s already in the garden, just be sure to loosen up the soil before you plant. There are a few different ways you can sow your seeds. You can mix them with a little bit of builder’s sand so that you can see where you’ve already broadcast and make sure you hit all areas of your sowing space. Or, you could mix your seeds with a little bit of the preexisting soil (they just may be difficult to see where you’ve sown), or you can just sow your seeds as they are, scattering them where you’d like them to grow. With bigger seeds, I like to poke them into the earth. The rule of thumb is to plant your seed as deep as the seed’s width. With small seeds, I’ll scatter them in the area of my choosing, and then scatter a little bit of vermiculite on top. This helps me see where I’ve planted them, and it helps cover the seeds a little bit so they stick and don’t get swept or washed away as easily, and the vermiculite allows light to reach them. Don’t forget to water your seeds in! And try to keep your seeded site moist until winter is fully upon us.

Here is a great video with visuals and a step-by-step guide that’s worth watching: 

Learn more

This is an area of the garden that I had freshly planted with nursery-grown perennials and wanted to fill the spaces in between economically. I scattered a wildflower seed mix, kept them watered, and let nature do the rest!

This is the same area of the garden from the photo above! The gaps between my nursery-grown perennials are filled with coreopsis, celosia, alyssum, poppies, and phlox, all grown from seed! 

Some considerations to keep in mind when sowing seeds in the fall:

Watch for super heavy rains, birds and mice, and other natural forces sweeping away your precious seeds before they’ve had a chance to grow. Not all of the seeds listed on your seed mix packet may bloom in the first, second, or even third year. Be mindful not to weed out tender new growth in the spring when you’re clearing away leaves and weeds. Labeling or keeping a garden journal can help identify seedlings from weeds. 

Hopefully, you’re feeling more prepared to add fall seed sowing to your list of garden chores! Starting seeds in the fall and overwintering them outdoors in the natural elements can be an economical way to start a wildflower patch, fill in a pre-existing garden or experiment with seed mixes and see what likes growing in your garden. A little bit of time and a few dollars investment can be well worth the blooms that ensue, and you’ll have flowers and plants earlier in the season than you would if you were waiting to sow your seeds after the last frost!

Most importantly, have fun with it! Enjoy the experiment of it all trusting Mother Nature to do her thing. Be proud of your hard work and dedication to your garden, and may you have many happy spring blooms in your future!