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Sunflower Success: How To Grow Sunflowers Indoors

Let the Sun Shine!

Now, more than ever, you may be feeling the impulse to bring the sunshine indoors. Indoor sunflowers are a beautiful way to keep your home bright and happy all year long! Outdoor gardeners rely on a warm growing season and plant sunflower seeds after the last frost of the year. When planting outdoors, the sunflower thrives in Hardiness zones two to eleven.  

But, when planting indoors, we’re free to improvise. So, let’s explore some sunflower gardening tips to help you get started on your very own sunshine garden – and excellent cut flowers. And a tasty snack!

The first step will be to choose the type of sunflower plants you want to grow, as the varieties vary in size, look, and seed production.

Why Grow Sunflowers Indoors Vs Outdoors?

There are several reasons to grow sunflowers indoors. The main reason is that you can control some of those pesky growing factors, specifically the temperature. Sunflowers do very well in warm temperatures, but if you live in an area where it’s cooler, or if there’s a risk of frost, putting them outside isn’t a great option. But you can have sunflowers year-round when you grow them indoors!

And if you want to eventually move your sunflowers outside for the world to see, that’s a great option too. Growing them indoors gives you a head start, specifically on some big plants.

Looking for other great plants to grow inside? Start with the beautiful Philodendron Birkin or Hoya australis.

Types of Sunflowers

Of all the sunflower varieties, indoor gardeners generally prefer dwarf varieties. Each of these small varieties can easily be grown in pots and containers. Here are some common types of dwarf sunflowers.

    teddy bear sunflower plant in the garden

  • Teddy Bear sunflowers can grow two to three feet tall and can have multiple blooms on one stalk. Their blooms resemble bright yellow poof balls and lack the flat, dark, seed-filled center usually associated with sunflowers.

Buy Teddy Bear Sunflower Seeds Here

    big smile sunflower plants in soil

  • Big Smile sunflowers produce a single flower and grow up to eight inches tall. They are the perfect indoor sunflower because up to three can be grown in a six-inch diameter pot.

Buy Big Smile Sunflower Seeds Here

    eight pacino sunflowers in garden

  • Pacino sunflowers can reach two feet tall and produce several yellow flowers.

Buy Pacino Sunflower Seeds Here

    helianthus annuus sunflower close-up photo

  • Helianthus annuus is often called the common sunflower. It is a stout annual that stands between 1.5 and 8 feet tall. It has a large flower that’s popular with many growers.

Buy Helianthus annuus Seeds Here

Other popular small sunflowers include Jade, Valentine, Little Becca, Dwarf Incredible, and Topolino. There are many different varieties of sunflower to enjoy!

If smaller flowers aren’t your aim, giant sunflowers and other tall varieties can also be grown indoors if you have enough space and light. The Mammoth Sunflower is an especially popular seed packet that’s known for its seed production. Remember though, taller sunflower varieties may not work as well inside most homes. You’ve been warned!

However, you will need a planter capable of holding at least 5 gallons of soil. Check out this variety pack of sunflowers on Amazon today.

Seed Storage

If you’re new to the seed-starting game, we should point out that seeds are weirdly difficult to store. There are just so many of them that it becomes confusing what each seed is, how old the seed is, and how to organize it from other seeds. Kevin from Epic Gardening recommends using a plastic photo organizer, allowing you to add your seeds by type in each compartment. We definitely suggest this option if you’re trying to stay organized.

Starting Sunflowers Indoors

To start your sunflowers indoors, first plant three seeds in 3- to 4-inch peat pots or seed trays. You’ll want to use a good quality general-purpose potting soil that supports good drainage but retains moisture. Plant the seeds no more deeply than the depth of your fingernail. Lightly water your soil so that it is moist but not overly damp. Sunflower seeds do not need overhead light to germinate, but it will be a requirement once you have sunflower seedlings.

Why Start Sunflowers Indoors?

Even if you plan to eventually move your sunflowers outside, there are still reasons you could want to start your sunflower seeds indoors. The main reason is temperature. If the temperature outside is 50 degrees or lower, it doesn’t create an ideal environment for seed germination. The best option for sunflower seeds is a temperature between about 67 and 87 degrees Fahrenheit. So it may be a good idea to bring your seeds inside if your outside temperature doesn’t fall in this range.

How Long Does It Take For Sunflower Seeds To Germinate?

Indoor germination takes 6 to 10 days on average, and outdoor seeds typically take 10 to 14 days to sprout. The key factors for germination are water (lightly moist) and heat (60-80 degrees Fahrenheit). Sunflower seeds to not need light to germinate.

How Do I Make Sunflower Seeds Germinate Faster?

One method to encourage faster generation is soaking the seeds in water for 6-8 hours. While not required, this option has been shown to speed up the rate at which your young plants sprout. Make sure you don’t soak them for more than 24 hours, which could cause them to rot.

How Long Should I Soak Sunflower Seeds Before Planting

You can soak your sunflower seeds 6-8 hours typically, but be careful not to leave them in water, which can cause the seeds to rot.

Sprouting Sunflower Seeds In A Paper Towel

While you can pretty easily germinate sunflower seeds in soil or a potting mix, a lot of indoor gardeners swear by starting your seeds with the paper towel method. To do this, you’ll need the following supplies:

  • paper towel
  • spray bottle
  • plastic bag
  • seeds
  • a label for the bag (if you’re germinating multiple types of seeds at once)

First, take a single paper towel, moisten it with water, and then lay it on a surface. Evenly spread 10 seeds on the wet paper towel. Cover the seeds with another sheet of paper towel and then use a spray bottle to moisten the top sheet. The top sheet should now cling to the seeds and the lower paper towel, sealing them almost like an envelope.

Take your sunflower envelope and gently slide it into a regular plastic baggy. Seal it most of the way, but leave about a one-inch opening for air circulation. The plastic bag will help create a humid environment, which can support and accelerate germination.

Once your seeds have germinated, transplant the entire peat pot, removing any portion that remains above the soil. This prevents the pot from pulling moisture up and away from the root. 

If you are growing outdoors, it is perfectly acceptable to sow seeds directly into your soil. However, be sure not to plant until any danger of frost has passed. In many climates, this does not take place until mid-summer.

Place the seeds in a place that gets indirect light.

When you see sprouts (which can happen within 3-5 days), transplant your young seedlings to a pot with soil. You can take scissors and cut out 3 seeds for each pot. No need to remove the excess paper towel. It will decompose within about two weeks in the soil.

Sunflower Care

Sunflowers are a member of the asteraceae family. Their giant flower is actually made up of many tiny blooms, which can come in a variety of colors. Check out this full list of care tips for growing sunflowers


I’m going to go ahead and say that drainage holes are the most critical feature in a planting pot. No matter how excellent the make-up of your soil, without drainage holes, your sunflower is not going to be sunny or bright… or alive. Drainage and proper spacing can also help to prevent mildew.

For varieties that grow two to five feet tall, you will want to allow about 6 inches between each seedling, while larger types should be placed at least one foot apart. If you plant sunflowers closer together, it may result in smaller flowers (which could be a good thing for some varieties).

After you have transplanted it into your pot, mulch can be added on top of the soil, carefully avoiding the stem. This will help to prevent moisture loss through evaporation.

sunflower in a black vase near window sunlight

Best Soil For Sunflowers

Sunflowers are heavy feeders and fast growers, meaning they need a loose and well-draining soil or potting mix that’s nutrient-rich and full of organic matter. In terms of PH, they should be kept between 6.0 and 7.5. Most general-purpose potting soil, such as this organic potting soil from Valley Garden.

Best Fertilizer For Sunflowers

While sunflowers are one of the easiest flowers to grow, a little fertilizer can go a long way. Slow-release fertilizers such as Mircae-Gro Water Soluble Bloom Booster or Esponma FT3 Flow-Tone Blossom Booster Plant Food are great options for sunflowers, whether they’re grown inside or out.


Sunflowers certainly earn their name for their sunny esthetic, but also for their love of sunlight. They enjoy full sun for at least six hours a day. The more direct sunlight, the better for the stem to grow thick enough to support its large flower. So ideally, you want to place your sunflowers in a sunny spot such as a south-facing window.

We don’t all have the luxury of the long warm summer, in which sunflowers thrive. In colder climates, or for year-round, indoor growth, a grow light may be required. You can find many different styles of grow lights on Amazon. Before you buy, take a look at The Best Grow Lights For Indoor Plants And Small Spaces.

While most grow lights would work find for a sunflower, the best long-term solution is likely an LED grow light, which is more energy-efficient and produces full-spectrum light.

Water Needs

During germination, it is vital to keep your sunflower well watered. A mature sunflower requires deep watering until the first six inches of soil is moist, about once a week.


The sunflower can self-pollinate between flowers, but it’s not great at doing this on its own. Outside, bees are expert pollinators. 

But inside, you’ll need to “be the bee,” by moving pollen from one flower to another. This is similar to the way that you would pollinate an indoor tomato plant.

You can be an expert pollinator with this fun tool from AeroGarden.

How To Grow Sunflowers Hydroponically

When growing sunflowers indoors, urban gardeners usually start asking about hydroponics. Simple DIY hydroponics – or even a countertop hydroponics system like AeroGarden – are able to grow indoor sunflowers easily. Here’s a quick video on growing your sunflowers hydroponically:

The main problem that growers have is the height of the grow light.

With the exception of some dwarf varieties, you’ll have over 18″ of growth, meaning you need to have a grow light that can grow with your plants. 

Here are some grow light options that may be able to help you:

Shop Related Products

When growing sunflowers hydroponically, you’ll need to add nutrients to your water reservoir. Here are some top brands for general hydroponics:

Sunflower History (More Reasons To Love Sunflowers)

It’s important to know who you’re sharing your home with, even the plants. To know them better, I’ll very briefly touch on the rich history of the sunflower.

The sunflower (Helianthus annus) is one of the few crop species, now grown around the world, that originated in North America. They are thought to have been derived from wildflowers as far back as 1000 BC. 

The sunflower is an annual plant that grew abundantly in the great plains, and Native Americans cultivated their seeds for meal and oil used in medicines and for cooking. When European settlers arrived, the sunflower was brought overseas in time to grace Van Gough’s easel and became a major agricultural crop in Russia in the late 1800s. 

The sunflower has primarily been seen as a crop flower until rather recently. It is now prized for its beautiful cut flowers, it functions as a living bird feeder, and as an ornamental plant. No longer exclusive to the rural countryside, the sunflower has now become a small garden and indoor favorite thanks to the development of many smaller varieties. 

yellow sunflower and harvest seeds

Harvesting Sunflower Seeds

Of course, we don’t only love sunflowers for their cheery disposition and rich history, also for their vitamin-rich, edible seeds.

When growing sunflowers indoors or out, they must receive lots of sunlight. They must also be kept warm. The ideal soil temperature for germination is between 70-75 degrees.

Sunflower seeds will naturally dry and fall off of the seed heads as they become heavy and droop toward the ground. However, when you are ready, cut the flower heads off, leaving several inches of stem attached. These sunflower heads can be hung in a dark, dry place as they continue to dry. 

If you are growing your sunflower outdoors, tie a paper bag or netting around the seed head to catch any falling seeds and protect them from rodents and birds. Little critters love to make a healthy snack of sunflower seeds.

Growing A Year-Round Sunshine Garden

When growing indoors, your sunflower knows no growing season. Use success planting to continually have blooming flowers. Either plant multiple varieties with varying days to maturity or plant the same or various types in one to two-week intervals. Final Thoughts

See, it’s easy to plant indoor sunflowers and enjoy your sunflower plants year-round. Either to harvest your own sunflower seeds or just enjoy their sunny disposition, open the windows, prep your pots, and let the sun shine!

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