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The best time to plant ornamental kale and cabbage is in late summer to early fall, roughly 6 to 8 weeks before your average first frost date.
Knowing when to plant ornamental kale and cabbage is the secret to getting those gorgeous, vibrant rosettes of purple, pink, and cream that light up the autumn garden.
If you plant these beauties too early in the summer heat, they’ll struggle and stay leggy instead of forming those tight, colorful heads we all love.
On the flip side, waiting too long into the cold season means they won’t have time to establish roots before the ground freezes solid.
In this post, we’ll dig into the perfect timing for planting ornamental kale and cabbage, how to adjust your schedule based on your climate, and a few tips to keep them looking stunning all season long.
Let’s get those fall beds ready.
When to Plant Ornamental Kale and Cabbage for Best Results
When to plant ornamental kale and cabbage really comes down to working backwards from your first frost date.
These cool-season crops actually thrive when the weather starts to chill, because the cold triggers the color change that makes them so attractive.
The general rule of thumb is to get them in the ground while there’s still enough mild weather for them to settle in, but not so much heat that they think it’s summer.
Let’s break down the specific timing windows so you can mark your calendar with confidence.
1. Count Back 6 to 8 Weeks from Your First Frost Date
The most reliable way to figure out when to plant ornamental kale and cabbage is to check your local frost date.
Your first frost date is the average day in fall when temperatures dip to 32°F or lower.
You’ll want to plant ornamental kale and cabbage about 6 to 8 weeks before that date.
For example, if your first frost hits around October 15th, you should be planting in late August or early September.
This gives the young plants enough warm-ish weather to establish a strong root system without pushing them into a growth spurt that ruins their shape.
By the time the frost arrives, they’ll be mature and ready to show off their true colors, which actually get brighter after a light frost.
2. Aim for Soil Temperatures Between 50°F and 70°F
Beyond just the calendar, checking soil temperature helps you nail down when to plant ornamental kale and cabbage.
These plants prefer cool soil, not cold soil, so you’re looking for a sweet spot.
If the soil is still baking in the 80s from summer, the seeds or transplants will just sit there or bolt quickly.
On the other hand, soil below 45°F will slow their growth to a crawl, leaving them stunted before winter.
You can use a simple soil thermometer to test the ground in your garden bed before you commit to planting.
When the soil reads consistently between 50°F and 70°F, that’s your green light.
This aligns perfectly with that late summer to early fall window for most regions.
3. Start Seeds Indoors 4 to 6 Weeks Earlier
If you’re growing from seed, your timing for planting ornamental kale and cabbage shifts a bit earlier.
You’ll need to start those seeds indoors about 4 to 6 weeks before your intended outdoor planting date.
So, using the same example, if you plan to transplant in early September, you should sow seeds indoors in late July.
This gives the seedlings time to grow strong enough to handle the transition outside.
Starting seeds indoors in the heat of summer is totally fine, just make sure they get plenty of light and good airflow so they don’t get leggy.
Harden them off for about a week before moving them into the garden to avoid shocking their systems.
Adjusting Planting Time for Your Climate Zone
Your local climate will heavily influence when to plant ornamental kale and cabbage, so it’s important to adapt the general rule to your specific area.
Gardeners in different hardiness zones won’t share the exact same planting window, even if they’d like to.
Let’s look at how to tweak your schedule based on where you live.
1. Northern Climates with Early Frosts
If you’re in a northern region like the Upper Midwest or New England, your first frost can arrive as early as late September.
That means planting ornamental kale and cabbage should happen in late July or early August.
You’ll be planting these guys while it’s still pretty warm, but they can handle it as long as you keep them well watered and maybe provide a little afternoon shade.
The payoff is that they’ll be fully mature and brilliantly colored by the time the first hard freeze rolls around.
You can even keep them going through early winter with a simple row cover or cold frame.
2. Southern Climates with Late Frosts
In the South or other mild winter areas, your frost might not come until November or even December.
So when to plant ornamental kale and cabbage shifts later, usually into September or early October.
You can often get away with planting even later down South because the winters are so mild.
Just be careful not to plant too early in September if the heat is still intense, those plants will sulk and may not color up nicely.
Wait for a stretch of cooler nights, and you’ll be rewarded with a long, colorful display that lasts well into winter.
3. Mild Coastal Regions
Coastal areas with moderate temperatures year-round have a bit more flexibility with planting ornamental kale and cabbage.
You can often plant in both early fall and again in late winter for a spring show.
In these zones, the frost date isn’t as critical, so you can focus more on soil temperature and day length.
Just avoid planting during the wettest, coldest months when growth stalls completely.
Aim for the same 6 to 8 week window before your expected coolest weather, even if there’s no true hard freeze.
Tips for Success After You Plant Ornamental Kale and Cabbage
Once you’ve nailed down when to plant ornamental kale and cabbage, a little aftercare goes a long way.
These plants are pretty low-maintenance, but they do have a few preferences that can make the difference between okay and spectacular.
Follow these simple tips to keep your fall garden looking its absolute best.
1. Water Consistently but Don’t Drown Them
Ornamental kale and cabbage like consistently moist soil, especially during their first few weeks after planting.
Water deeply at the base of the plant rather than overhead to keep the leaves dry and prevent fungal issues.
A nice layer of mulch around the base will help retain moisture and keep the roots cool.
Just don’t let them sit in soggy soil, as that can lead to root rot.
Check the top inch of soil regularly and water when it feels dry to the touch.
2. Feed Them Lightly for Steady Growth
These are light feeders, so you don’t need to go heavy on the fertilizer.
A balanced, slow-release fertilizer at planting time is usually enough to carry them through the season.
Too much nitrogen will make them grow fast but with washed-out colors and loose, floppy heads.
If you want a little boost, side-dress them with compost or a low-nitrogen fertilizer once about a month after planting.
Remember, the cold is what really triggers the vibrant colors, not heavy feeding.
3. Don’t Panic Over Light Frosts
A light frost is actually your friend when you’re growing these plants.
The cold causes the sugars in the leaves to concentrate, which deepens the pinks, purples, and creams.
So don’t rush to cover them the minute the temperature dips below freezing.
They can easily handle temperatures down to about 20°F without much damage.
For harder freezes, you can throw a frost blanket over them to extend the season, but many gardeners just let them be.
So, When Should You Plant Ornamental Kale and Cabbage?
You should plant ornamental kale and cabbage about 6 to 8 weeks before your average first frost date.
That sweet spot in late summer to early fall allows them to establish roots in warm soil while the cooler days ahead trigger their stunning colors.
Adjust that window based on your climate, starting seeds indoors earlier if needed and shifting later in milder regions.
When to plant ornamental kale and cabbage doesn’t have to be complicated, just sync your schedule with the natural cooling of the season.
We hope this guide has cleared up any confusion about planting ornamental kale and cabbage and given you the confidence to get them in the ground at the perfect time.