For earlier pops of color, a buffet for pollinators, and overall hardier plants, gardeners should be growing cool-season annuals — flowers that are started in fall or very early spring and bloom weeks or months earlier than heat-loving plants. To offer a primer on successfully planting and growing these flowers, my guest this week is flower farmer, teacher and author Lisa Mason Ziegler.
Lisa is the founder of The Gardener’s Workshop in Newport News, Virginia, which offers seeds, supplies and online courses, and is the author of “Vegetables Love Flowers: Companion Planting for Beauty and Bounty” and “Cool Flowers: How to Grow and Enjoy Long-Blooming Hardy Annual Flowers Using Cool Weather Techniques.” She’s been farming flowers on the line of USDA hardiness zones 8A and 7B for nearly a quarter of a century and is generous with sharing what she has learned in that time.
To help you determine the right time to plant in your zone, Lisa is sharing her list of cool-season annuals with their hardiness zones identified. If an annual is winter hardy in your zone, it can be planted in fall or very early spring. If it’s not winter hardy, it can still be planted in very early spring. Find this helpful sheet at joegardener.com/coolflowers.
Before continuing my conversation with Lisa, let me pause to remind you that I have a book of my own coming out next month. The title is “The Vegetable Gardening Book: Your complete guide to growing an edible organic garden from seed to harvest,” and it’s available for pre-order now. It’s chock full of insider tips and new-to-you information that will help you step up your gardening game and tackle challenges.
And on tap for 2023 is my new Online Gardening Academy™ premium course, Organic Vegetable Gardening. Sign up for the waitlist here.
An Opportunity That Shouldn’t Be Missed
In terms of vegetable gardening, many gardeners believe that when the summer’s over, vegetable gardening season is over, but that couldn’t be further from the truth. Neglecting to plant fall crops for a cool-season garden is a missed opportunity. When it comes to flower gardening, the same thing goes. There are cool-season flowers that should be planted now to enjoy this fall and even into the winter.
Which cool-season annuals to grow and when to plant them varies by location. “It’s all about where you live,” Lisa points out. “We have different timing for different regions.”
Many growers can put baby plants in the ground in fall that will overwinter successfully and become the earliest, most abundant, easy-care flowers of the spring to early-summer garden.
“It is a frightening experience to think about planting a little plant outside just when winter’s around the corner and on its way,” Lisa says. But she explains that she actually launched her flower farm with cool-season annuals back in 1998, and she stressed that it was easy. “I was barely a gardener, much less a farmer when I started,” she says. “I had such great success with little input from me just because I timed it properly.”
Fall Planting Changes Winter
Lisa jokes that when she married her husband, Steve, he came with a dowry: a huge garden. Well, she turned that garden into a flower farm based on the advice in Lynn Byczynski’s renowned book “The Flower Farmer.” The book was a huge source of inspiration for Lisa, and she credits Lynn with planting the seed for most of the farmers in the cut flower industry.
It was already August when Lisa finished reading “The Flower Farm,” and she was raring to plant. The book recommended a few flowers that could be planted in fall: snapdragons, sweet peas and sweet William.
At the same time, Lisa was new to seed starting. She was reading books by market gardener Eliot Coleman and learned about soil blocking, which uses compressed soil mix for starting seeds instead of seed starting mix in pots. She says she was an “overnight success seed starter,” growing snapdragons, sweet peas and sweet William in soil blocks. She then transplanted the seedlings into the garden three to five weeks later, depending on the flower.
“The greatest part of fall planting this group of flowers is it changes winter for you,” Lisa says. Instead of sitting in the house and not bothering to look out the window, the first thing you think of when you get up in the morning is “I wonder if they’re still alive. I wonder if they’re still out there,” she says. “You are peeking out the windows. You’re putting on your coat and going out there — when you otherwise wouldn’t — to look at your frozen little plants.”
She says that the following spring she had an incredible garden despite knowing nothing. That lit a fire in her, and she set out to find more flowers that she could raise the same way. In fact, she still uses the same method of seed starting today.
Of course, different seeds call for different germination methods. Lisa does what the seed prefers.
“Some people say, ‘Oh, well I’m just gonna direct sow everything,’” Lisa says. “Well, you can do that, but you probably won’t have a lot of success with many of them.”
She only direct sows in the fall. In the spring and summer, she refrains from direct sowing because of weed and heat pressure.
“There’s a handful that I direct sow, but there are a lot more that I plant from transplants in soil blocks,” Lisa says. She seed starts nearly year-round. In the North, the window for indoor seed starting is limited because of the shorter growing season, but there are still plenty of opportunities for succession planting.
Lisa is a big believer in planting as much as you are able to in the fall. Snapdragons planted in fall will have better pest and disease resistance, greater abundance and longer stems than snapdragons planted in spring, and they will bloom longer in summer heat because they are better established, she says.
Fall’s also a great time to plant because the pest and disease pressure is reduced and the humidity is down — it’s much easier on the plants and a much more comfortable season to work in for gardeners.
In the mid-United States and points south, these annuals can be planted year-round — basically, whenever the ground is not frozen.
From the time of direct sowing until the frost comes, Lisa hoes between the rows every week to control the weeds. That gives the seedlings a huge advantage over the weeds.
Lisa harvesting snapdragons.
Direct Sowing Vs. Transplanting
Lisa prepares two different types of beds: one for direct sowing, one for transplants.
The beds for direct sowing are prepared immediately before sowing so weed seeds won’t have a head start over the flower seeds. These beds have no mulch so the seeds will have light exposure.
To prepare a transplant bed in fall, Lisa’s farm uses flower support netting as a planting grid. For mulch, they use a biodegradable mulch film called Bio360. It’s very effective for weed suppression, particularly for winter weeds like chickweed and henbit, Lisa says. Holes are punched in the film where the soil block transplants will go in early in spring.
Lisa says it’s easy for farmers to put a transplant into a bed that’s been prepped with a weed barrier rather than direct sowing seeds that will compete with weeds and need to be watered almost daily.
Over the flowers, AG-19 row cover is installed on hoops. AG-19 is the lightest weight row cover and allows 85% of air, water and light to get through. Over the winter, the row cover is effective at protecting the plants from cold wind. Rarely does the temperature dip into single digits on Lisa’s farm, but when it’s a concern, they simply double up on AG-19.
As a general rule, six to eight weeks before your first winter frost is your target date to plant transplants or direct sow seeds. Whether seeds or transplants, six to eight weeks is how long they need to get established before going into winter if they are going to survive. (She starts seeds in soil blocks four weeks before she intends to transplant them.)
A direct-sown seed will establish quicker in place than a plant that germinated indoors, which will require some time to recover from transplant shock.
Lisa direct sows seeds that she knows will benefit from the temperature change they experience outdoors — cool nights and warm days. That change stimulates the seeds to break dormancy and germinate.
Larkspur, for example, is looking for 55-60° at night and 70–75° days. “That would be very difficult to do in your home,” Lisa points out. Bells of Ireland is another example of a direct sower.
Lisa notes that, due to climate change, she now plants later and later every year. Planting too early is a very common mistake, she says. It’s important not to plant early because plants that grow too big won’t be as winter hardy. “It’s just too mature,” she says.
When deciding if the time is right to plant, Lisa disregards daytime temperatures and pays attention to nighttime temperatures. She is looking for 60-65° and holding for two weeks.“The weather is unpredictable, and that’s why farmers are a little crazy, you know,” Lisa says. “This is what makes us crazy.”
She doesn’t use a soil thermometer, as she finds that just makes things more complicated.
A Key Time Period: Very Early Spring
When most people are thinking about planting what she calls Very Early Spring flowers, those flowers should already be blooming, Lisa says.
She defines Very Early Spring as six to eight weeks before your last spring frost. Seeds aren’t going to germinate outside in the garden when it’s 25° at night, she says, but transplants will be ready to be put in the ground.
Stock (Matthiola incana) is an attractive, fragrant flower that many people would love to grow but have trouble with because it can’t stand the heat. “It looks kind of like a snapdragon, but it’s a lot more luscious and it has this amazing spicy smell,” Lisa says. To grow it successfully, she advises getting transplants in the ground in Very Early Spring.
She starts stock seeds indoors in January for mid-February transplanting and has cut flowers by Mother’s Day. She says if she waited until April to plant, the flowers couldn’t take the heat.
What to Know Below Planting
Two pieces of information you need to obtain before planting flowers, according to Lisa, are your winter hardiness zone and your first and last expected frost dates.
First and last frost dates are not as reliable as they once were in light of the unexpected weather that climate change has brought, but knowing these approximate dates gives you a jumping-off point to make plans.
Your winter hardiness zone tells you what you can plant in fall that can overwinter, and your first frost date and last frost date tell you when you can plant.
The bottom line for cool-season annuals is the timing. They won’t succeed if planted too early or too late.
“All of these cool-season annuals go into the heat and humidity of our summers with a whole new armor on now because they’re so well established,” Lisa says.
Poppies on Lisa’s flower farm.
Lisa’s flower farm has conventional beds and beds where they practice no-till gardening.
In the no-till area, they prepare for planting by topdressing with two inches of compost and adding a dry organic fertilizer for a low dose of plant food.
“We typically get two to three crops out of almost all of our beds,” Lisa says. “So you have to feed the soil.”
She says the farm can never have enough compost, far more than they can make, so they buy it. However, they don’t pay for mulch. When they do use mulch, it must be chemical free — and free.
For her tilled beds, the farm uses a “bed maker,” a tractor implement that forms the bed and lays the irrigation and mulch film all in one swoop. “It is a site to behold,” Lisa says. “It brings tears to farmers’ eyes who don’t have one.” The tilled beds also receive dry organic fertilizer.
Raised beds are essential for this group of flowers because of the rain, snow and ice that come with winter, according to Lisa. Drainage problems are not apparent in summer when heat dries up beds quickly, but in fall, winter and very early spring, that water will collect and just sit there, and that’s a problem because cool-season hardy annuals are particularly sensitive to wet feet.
“That just induces so many diseases, and it just sets the plants up not to be healthy,” Lisa says. “So raise those beds as much as you can and that’ll just make the experience better and better.”
Full sun is always best for siting cool-season annual beds. If you’re dealing with shade from deciduous trees, early spring bloomers like poppies and bachelor’s buttons are your friends. They will bloom in March (depending on where you live) before the trees put their leaves on and cast shade. And bachelor’s buttons, aka cornflowers, excrete nectar from their flowers as well as their foliage, which is why they attract so many beneficial bees and wasps.
Early Spring Bloomers & Insect Activity
Lisa says that when she started out farming and gardening 25 years ago, “organic” wasn’t talked about much. “It was like you were a hippie if you even said the word ‘organic,’” she recalls.
Though she didn’t set out to be an organic gardener, she fell into it after trying to battle pests in myriad ways.
“I finally just threw up my hands and said, ‘All right, y’all duke it out,’” she recalls.
She let the pests go head-to-head with beneficial insects, and came back later to harvest what flowers were left. Over two or three years, her garden transformed. What she learned is that her efforts to battle pests had also been eliminating the beneficial insects that prey on those pests. When she stepped back, the good bugs were again able to control the bad bugs.
“Nature kind of restored itself here on my farm, and it is a sight to behold,” she says.
Not only did assassin bugs and other predatory insects come in and do the work of pest control for her, but the pests also became bird food.
“Birds are huge consumers of insects, particularly caterpillars,” Lisa points out.
Because Lisa’s gardens are blooming six to eight weeks earlier than most, they attract so many pollinators and predatory insects. For example, her Rudbeckias, which she plants in fall and that bloom by Mother’s Day, are a favorite of native bees.
“We have quite a community of native bees here on our farm,” she notes. “We have longhorn bees, and they are — I mean, if you’ve never seen ’em — they are just the cutest little things ever.”
She doesn’t know how anyone can garden organically without a strong presence of flowers. “It’s just the easy way to do it, y’all,” she says. “It’s the way the world was made to work.”
Some Favorite Cool-Season Annuals to Grow
When Lisa published “Cool Flowers” in 2014, she featured 30 types of flowers. Since then she’s learned so much more, and now her list of cool-season annuals has nearly doubled in length.
Sweet peas have a wonderful fragrance and are winter hardy to zone 7. If you live in zone 7, 8 or 9, fall is the time to plant them. They will take off the following year.
Sweet peas like it much cooler than people think, Lisa says. To get the seeds started in soil blocks, she doesn’t use seedling heat mats. Instead, she sets the soil blocks with the seeds in them outside when the nights start going down to 55°. A couple of weeks later, the plants are 6-inch vines and ready to be planted in the ground.
The list of flowers that Lisa direct sows in fall rather than starting indoors is short. Though many seeds can go either way, she has gained a sense of which seeds truly do best when they are direct sown and which benefit from being started indoors: corncockle, dill, Bupleurum, bachelor’s buttons, larkspur, bells of Ireland, love-in-a-mist and poppie.
These snapdragons were fall planted.
I hope you enjoyed my conversation with Lisa Mason Ziegler. If you haven’t listened yet, you can hear this episode now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
What cool-season annuals do you grow? Let us know in the comments below.
Links & Resources
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joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course membership opens in 2023. Sign up for the waitlist here.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out.
joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier.
joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
“Vegetables Love Flowers: Companion Planting for Beauty and Bounty by Lisa Mason Ziegler
“The Flower Farmer: An Organic Grower’s Guide to Raising and Selling Cut Flowers” by Lynn Byczynski
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, AeroGarden, Milorganite, Soil3, Greenhouse Megastore, PittMoss, Territorial Seed Company, Earth’s Ally and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.