An eye-catching staple in summer gardens, can you grow woolflowers in the peak of winter? Find out how much cold Celosia can tolerate.
A member of the Amaranth family, celosia blooms are dazzling with fiery hues and unique textures. Their young spinach-like leaves are edible, and they make for perfect border plants. But can these sun-loving plants tolerate cold?
Get to Know Celosia
This Mediterranean and East African native is split into cultivars based on flower structure. Plumed celosia produces tall, feathery blooms, while the wheat cultivar has flowers that mimic the grain crop. And cock’s comb blooms are hefty with a brain-like appearance!
Celosia is typically grown as an annual in most USDA zones. However, in zones 9b to 11, it can be grown as a tender perennial in a bright spot with well-drained, fertile, organically rich, slightly acidic soil with a pH of around 6 to 7.
How Cold is Too Cold for Celosia?
Celosia is quite sensitive to chilly weather. It prefers gardens to containers, so plant it outdoors once nighttime temperatures are consistently above 50 F (10 C). Celosia blooms from summer until the first frost.
The plant cannot tolerate frost, and—anything below 30 F (-1 C) will cause serious damage. Even when temperatures dip below 50 F, the plant reduces its growth. That’s why it’s best to plant celosia in late spring or early summer when the weather is more stable.
However, if you live in a warm climate, fall is the best season to start your celosia plant. In frost free regions, this lovely flowering plant enjoys long growing season from fall to spring, which sometimes can extend to early summer!
While it’s possible to grow celosia in pots, container plants are more vulnerable to temperature fluctuations. The soil in pots cools down faster than garden soil, leaving your celosia exposed to the cold; this is why it’s important to provide protection by wrapping the pots with a bubble wrap when temperature cools down to extend its life.
Note: Celosia blooms do not fall off naturally even after they die; you need to deadhead them to keep the plant looking fresh.
Signs Of Cold Damage in Celosia
If your celosia is exposed to extreme cold, the damage will show quickly. One of the first signs is wilting or shriveling leaves.
Frost causes ice crystals to develop in the plant’s tissues, leading to cell damage.
The leaves turn brown or black, and growth slows significantly. If left in the cold for too long, the entire plant may die.
How To Revive Cold-Damaged Celosia
1. Provide Warmth in Winter
As winter approaches, the first obvious step is to shelter your celosia from frost. Cover your garden plant with a frost cloth to protect it from chilly nights. This creates a barrier between the plant and cold air, offering warmth.
For potted celosia, gradually reduce the light exposure and move it indoors near a warm grow lamp, giving the plant time to adjust. While you move it indoors, don’t forget to remove spent blooms as well.
Be gentle and avoid sudden transitions to prevent stress. Allow your celosia to acclimatize to its new settings gradually, and keep it on a bright windowsill.
2. Evaluate the Damage
Now, if your plant has already caught a cold, you may still be able to save it. Depending on how long your celosia has been exposed to cold, you can measure the severity of the damage.
While some plants die immediately after frost, if you catch the symptoms above early on, you can prevent further harm. The key is to take action before the cold reaches the roots. This gives your celosia a sliver of hope to revive!
3. Treat the Damage
If your plant now consists of wilted, dying leaves mixed with fresh, green foliage, it’s time to remove dead weight. Determine the areas that are rotting—discolored leaves, dropped buds, black spots on leaves, and more.
And if the damage is fresh, wait a few days before carefully snipping away the damaged bits.
How to Overwinter Celosia Outdoors?
It’s important to note that no efforts should be made to overwinter Celosia below USDA Zone 8b.
Below USDA Zone 9, it should be treated as an annual. However, in Zones 8b, 9a, and 9b, and above, you can take protective measures to save your plant and continue growing it.
1. Provide Ample Drainage
Celosia needs well-draining soil and full sun. So whether you plant them in your garden or a pot, ensure the medium is sandy and loamy. And to improve drainage and prevent frost build-up in winter, mix blood meal, compost, perlite, gravel, or azomite into the soil.
2. Mulch Around the Base
As the weather gets cooler, apply a 2-4-inch layer of mulch around the base of your celosia. Mulch keeps the soil insulated, prevents weeds, shelters from extreme heat and cold, and even amends the medium.
Use organic mulch, such as shredded wood products, pine needles, or leaf compost. This provides your plants with ample nutrients without leaching away any nitrogen in the soil. And don’t forget to check out these companion plants that help your celosia thrive!
3. Insulate the Plants
Provide insulation by covering your pots with bubble wraps or burlap, protecting the plants from cool weather. Also, keep the celosias in a sheltered spot from cold drafts and together with other plants to create a microclimate.
Celosia Germination Stages
The ideal temperature range for growing celosia is 70-80 F (21-26 C). While planting seeds, keep the soil slightly moist and maintain its ideal range to coax seeds into germinating within two weeks. And keep humidity levels at around 60-70 percent or even higher.
After germination, you can transplant the seedlings to a sunny spot in your garden. Following transplantation, celosia can thrive even if the temperature gradually drops to 60-65 F (15-18 C) during the day and 50-55 F (10-15 C) at night.
Starting Celosia Seeds
If you’re just getting started on your celosia journey, start your seeds indoors before the last frost date in warm, ideal conditions either in late spring or early winters. Indoors, you have the flexibility to adjust and control the light, warmth, and humidity settings.
Celosias grow comfortably outdoors in an unobstructed sunny spot in zone 9 and above due to less risk of frost. If you propagate them indoors from seeds, set your thermostat to 70 F (21 C) or higher for a while. Ensure temperatures are no lower than 64 F (18 C) at any given time.
Once your seedlings flourish in their tiny containers, transplant them outdoors when the weather has warmed up enough.
So that’s how you overwinter celosia. Remember to hold back on watering and fertilizers during winter and provide ample filtered sunshine.
