Container gardening is a great way to enjoy flowers’ beauty without committing to a large garden plot. And what better way to show off your burgeoning green thumb than by growing cheerful sunflowers?
Sunflowers can easily grow in containers if planted in rich, well-draining soil with regular water. Dwarf varieties will perform the best, but all types will need full sun. Sow the seeds directly into the container or transplant seedlings in. Keep the soil moist but not wet, and be sure to fertilize regularly.
This post will give you everything you need to know to grow sunflowers in containers, from choosing the right pot to selecting the best varieties. We’ll also share some tips on fertilizing and watering your sunflowers so you can enjoy these cheerful blooms all summer long.
So whether you’re a beginner gardener or an old pro, read on for our complete guide to growing sunflowers in containers.
Why grow sunflowers in containers and pots?
Growing sunflowers in containers gives gardeners more control over the soil, water, plant spacing, and garden location. It is a great way to extend the season in colder climates where the growing season might not allow them to mature.
Using containers to manipulate your garden season and space availability is worth it to squeeze in sunflowers. They are bright, cheerful, and generally easy to grow while being both ornamental and edible. With proper care and selection, some of the blossoms can be cut for bouquets, while others can continue growing to full maturity and produce seeds for next year.
Do your sunflowers need some companions in their pots? These two articles will inspire you to pack your pots with blooms:
- 12 Cut Flowers To Grow In Containers (Plus Tips For Success)
- Sunflowers Make The Best Companion Plant (17 Suggested Friends)
How to ensure your sunflowers grow well in pots
Growing sunflowers in containers doesn’t have to be complicated. But you should do a few things to set your plants up for success.
The mature size of your sunflower variety is what will dictate the size pot you’ll need. Check the seed packet to see how big the sunflowers will get, and choose a pot accordingly.
For dwarf varieties that only grow to be 2-3 feet tall, an 8-10 inch pot should suffice. But for taller varieties that can reach up to 6-8 feet tall, you’ll need a much larger pot, at least 18 inches wide and deep.
Tall sunflowers grown in a pot won’t have the chance to send their roots as deep as they might normally, which means they may not be anchored into the ground very effectively. To help keep them upright, stake tall sunflowers in containers with a bamboo stake or similar support.
The containers might need extra support as the sunflowers reach full height. The extra support will prevent the pot from tipping over in a strong wind or from an accidental bump as you walk by. Try wedging a few bricks around the base of the pot, or positioning it against a wall to protect one side of the plant.
To take full advantage of the ability to move your sunflower to more advantageous locations, avoiding heavier types of pot, such as terra cotta or clay, is a good idea.
Plant dollies, which are small platforms on wheels made specifically for holding potted plants, are a good idea for larger pots. Wheels make moving your sunflower from one area to another to take advantage of the best sunlight an easy task.
Soil for potted sunflowers
Sunflowers like rich, loamy soil that retains some moisture but drains easily. A standard potting soil mix will do well, especially with the addition of other fibrous materials, such as coco coir, peat moss, or rice husks.
Coarse materials should be placed in the bottom of the pot to keep the drainage holes from being clogged by the growing medium, then the growing medium should be layered in on top.
If you plan to move your plants indoors at the end of the growing season, it might be a good idea to have a barrier over the soil to prevent pets from digging in it.
Here are some of my favorite soil products for any garden, in-ground or container:
My favorite garden soil supplies
When you know what condition your soil is in, it’s much easier to add anything that’s missing before your plants start to suffer. Find out your soil’s pH and macronutrient levels with an easy Soil Test Kit. Even without a soil test, worm castings are a safe bet to add to any garden, and your plants will love them. Wiggle Worm Soil Builder is a high-quality amendment that I add to all my garden beds that need a boost. Finally, learn why I don’t till my garden anymore with the “godfather” of no-till, Charles Dowding’s No Dig Gardening.
Sunlight and water requirements
Sunflowers need at least six to eight hours of sunlight daily to thrive. Young sunflowers will swivel on their stalks to follow the sun’s path through the sky. As they mature, the heavy heads tend to lock onto an easterly position, making it a good idea to plant them in a spot where they can face the sunrise.
If you need to bring your container plants indoors before they’re fully mature, you will need a grow lamp to ensure that they get enough light to complete their growth cycle.
Sunflowers are thirsty plants. The exact amount of water they need will vary with pot and plant size, but a general rule is to add water when the top two inches of soil are dry.
Types of sunflowers to plant in pots
Annual sunflower varieties are the easiest to manage in containers because they grow a single plant from seed. You can start the seeds in starter pots about four weeks before you plant to transplant them, which I’ll walk you through in a later section.
Dwarf sunflower varieties will be your best bet for growing in containers. They’ll thrive with rich soil and regular water. Standard height sunflowers, or even mammoth sunflowers, can perform well, too, if you pay close attention to regular watering and fertilizing and choose a big enough container.
Perennial sunflowers tend to produce a large root ball that will increase in size each year. The root ball will require repotting and possibly dividing the root ball, which can be a delicate task, making them a poor choice for growing in containers. They can often be seen growing wild along the roadside in the midwestern states of the USA.
Lemon Queen Sunflower: A good variety to grow in a container. Once it has reached a height of two feet and is well-established, it is drought resistant. Produces multiple blossom heads, and is attractive to bees and other pollinators.
Sunny Bunch Dwarf: Cheerful yellow multi-head blossoms, with chocolate-brown centers. Perfect for containers or a garden border. Grows to about three feet tall.
Ring of Fire: Grows to about 4 to 5 feet tall. Petals are yellow at the tips, dark red toward the center, creating a gorgeous flame appearance.
Teddy Bear: A sunflower that is so fluffy that it looks cuddly, like a teddy bear. It has multiple rows of petals around a small, yellow-green center. Its multiple heads make it perfect for cut bouquets, and a near look-alike for Van Gogh’s famous blossoms.
Black Oil Sunflower: A classic yellow sunflower with dark center. Grows to around four or five feet. Excellent choice for snacking or to plant in a bird attracting garden.
Standard varieties of Helianthus annuus
Moulin Rouge: Deep red petals with a dark chocolate center. Grows to about six feet, absolutely stunning color.
Chocolate Cherry Sunflower: Dark red outer petals, with a dark chocolate center. Grows to six or seven feet, with a spread of about three feet. Be sure to use one of your larger containers for this one!
Russian Mammoth: When planted outdoors in the garden, it can reach ten feet. Get out the big pots for this one!
When to start sunflowers in pots
You can start sunflowers in pots at any time of the year. Remember that during the winter months, when days are short, you will need a grow light to provide enough light for them and keep them indoors.
Unless you specifically want to have sunflowers to grow indoors, wait until spring to plant.
The best time to start seeds indoors is about four weeks before the last frost date in your area. The seedlings will get a head start on the growing season without having enough time to grow too large to transplant successfully.
For outdoor sowing, wait until the risk of frost has passed and the soil has warmed up to at least 60 degree Fahrenheit to help encourage germination.
You can sow sunflower seeds up until a couple of months before your first fall frost, though they’ll grow a little slower as the days cool and shorten. Check out your last planting date in this article, How Late Can You Plant Sunflowers? Check Your Zone & Date Here.
How to successfully grow sunflowers in pots
Step-by-step, here’s what you need to do for a crop of health, beautiful sunflowers:
- Select a variety that suits your growing space (recommendations above).
- Pick out a large pot of appropriate size for that variety.
- Make sure the pot has adequate but not excessive drainage ports.
- Place a drip tray under the pot.
- Put coarse aggregate material in the bottom 1/3 of the pot.
- Fill the rest of the pot with rich, loamy soil with good tilth.
- Plant two or three seeds half an inch deep.
- Water daily until the seeds germinate.
- When the seedlings emerge, place the pot near a good light source that will give the seedlings 6 to 8 hours of direct sunlight or equivalent per day.
- Plan a trellis or stake to help the small sunflowers remain upright.
- Continue the watering regimen, keeping the plant sufficiently moist but not too wet.
How big of a container do sunflowers need?
Containers for sunflowers can be as small as an 8-inch pot, or the larger varieties might need a pot as large or larger than a ten-gallon utility pail. A half wine barrel is an excellent choice for potted sunflowers, as it’s large enough to support growth and sturdy enough not to tip over as the flowers grow.
How often should I water sunflowers in pots?
Some sources say “water when the top two inches of soil are dry,” while others recommend a small amount of water daily. The key is to keep the soil moist but not dripping wet, which usually amounts to about one inch per week.
Do sunflowers grow better in pots or ground?
In temperate zones where the soil is moderately fertile and the growing season is around 120 days, they really do best outdoors, especially giant sunflowers. But if you have heavily alkaline soil, or if your growing season is short, they will do better in pots.