How to Successfully Grow Sunflowers Indoors

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Sunflowers are bright, cheerful flowers that capture the essence of summer and sunny days. With their vibrant yellow petals and big heads turned towards the sun, they are one of the most popular flowers and a great favorite for many plant lovers. If you’ve always wanted to grow sunflowers but don’t have a garden, the good news is that sunflowers can be grown indoors.

Growing sunflowers is easy. All you need to do is gather a few things to create an ideal environment for your sunflowers to grow and thrive. Important considerations include choosing the best sun-lit spots, proper fertilization, watering, and pruning your plant in order to make sure your sunflowers live and bloom for as long as possible.

Things you will need

Before you start growing these lovely plants in your home, you will need to gather several items to help ensure that your sunflowers will grow and thrive in the best environment possible. Here is a list of items you will need along with a brief explanation of each.

  • Containers with drainage holes – Sunflowers need to be planted in a pot that has drainage holes so they grow to be sunny and bright. Pots that have drainage and proper spacing between the sunflower plants can also help to prevent surface fungi (also known as mildew) from growing inside your pot. You can get suitable pots on Amazon. Have in mind that the diameter should suit the type of sunflower variety you’re growing.
  • Potting mix – Sunflowers need a good, fertile soil that drains well but also retains its moisture. You shouldn’t only put soil, but add a layer of drainage material as well, such as gravel, terracotta pieces, or polystyrene foam at the bottom. After that, you can top it with potting soil. If you are planting in a larger pot, it’s best to mix the soil with vermiculite, a mineral that helps lighten the weight of the pots and promotes plant growth.
  • Fluorescent or incandescent lights – Growing sunflowers means ensuring that your plants have as much light as they possibly can, as sunflowers are one of those flowers that require an ample amount of light. Fluorescent or incandescent light (also known as grow lights) will help your sunflowers grow even during the winter or on the days when there isn’t enough natural light.
  • Saucers or trays – Placing saucers or trays underneath your sunflower pot will help catch the liquid that drains from the drainage holes. This will protect your furniture and floors from getting wet. Remember to always discard the drained water after the pot has drained thoroughly.
  • Watering can – The soil around your sunflower plant should be moist (not soggy) and a watering can will help you water the soil and not the actual foliage of the plant.
  • Low-nitrogen fertilizer – Sunflowers are easy to grow and don’t always need fertilizer. SFGate’s Home Guides advises you to check your soil and sunflower’s nutritional needs before you add fertilizer. Make sure to put low-nitrogen fertilizer, as too much nitrogen can cause the plants to grow very tall with lots of foliage but just a few flowers.
  • Stakes – According to MasterClass, some sunflowers can grow to be over 16 feet tall. While this is more common for outdoor sunflowers, you’ll also want to give your indoor sunflowers the support they need when they start growing. Using stakes will help support the weight of the sunflower heads.
  • Fabric-covered plant ties – When tying the stems to the stakes, you’ll want to use fabric-covered plant ties so you don’t damage the stem and leaves of the plant.

Planting your sunflowers inside

Sunflower seedling growing from a pot
Sunflower seeds grow into seedlings, and they’ll grow into tall, strong plants with a large yellow flower on top.

Sunflowers are usually associated with wide, open fields and sunny skies. Nevertheless, there are gardeners and plant lovers who have successfully grown varieties of sunflowers inside their homes through the years.

One such preferred sunflower is of the dwarf variety because they are smaller and can easily grow in pots and containers. Some of the more common types of the dwarf variety are the following:

  • Teddy Bear sunflowers – can grow up to 2-3 feet tall
  • Big Smile sunflowers – can grow up to 8 inches tall
  • Pacino sunflowers – can reach 2 feet tall

Other sunflowers that are also on the smaller side are Dwarf Incredible, Jade, Little Becca, Topolino, and Valentine.

If you want to grow giant sunflowers indoors, you can also do that, provided that you have ample space and light to do so. One of the more popular ones is the Mammoth Sunflower which can grow up to 12 feet tall. To make sure your sunflower will thrive, however, you’ll need pots that can hold at least 5 gallons of soil.

Regardless of the kind of sunflower variety you end up choosing, growing sunflowers indoors requires certain steps to ensuring that your plant gets the best care possible. From choosing the location to pruning and trimming it, here’s what you need to do:

Choosing the best location

When it comes to choosing the best location to place your potted sunflowers, you have to find a sunny location. Sunflowers are known for their love for the sunlight, so it’s important that they get it for at least six hours a day. Usually, a location near windows facing east or south is the most ideal.

The more direct sunlight they can get in a day, the more their stems will be able to grow and strengthen themselves to support the large, heavy flower. If you have a patio or balcony, you can place the pots outside so they get as much sun as possible as sunflowers won’t grow and bloom well if they don’t have enough light.

Grow light turned on and lighting several plants at once
Grow light is a great solution if sunlight is scarce. Click the image and see the options offered by Amazon.

If you are growing sunflowers through winter or if you live in a place where the climate is colder and sunlight is scarce, you might want to get a grow light to make up for the lack of sunlight.

Watering

Sunflowers need to be well-watered, yet it is important to make sure that the soil remains moist—not soggy. This is why you need to make sure that your pot has drainage holes and a tray to catch the water before discarding it. You will know if your soil is well-drained if water flows through it quickly.

After planting the seeds, water them daily. They need at least two gallons of water a week while the seeds are germinating. Sunflowers that don’t get enough water may end up with thin stems that are too weak to hold up the flower head.

When the seeds bloom into a flower, check first to see if the top inch is dry before you water it. Remember to avoid watering the stem and the plant directly, but water the soil instead. To help the sunflower grow better and faster, focus on giving it regular water 20 days before and after flowering.

It’s also important to give the sunlight lots of moisture. Gilmore recommends covering your pots with clear plastic wrap to trap in the moisture and only removing them when the seeds begin to sprout.

Fertilizing

Not all sunflowers need fertilizing which is why it’s important to check the quality of your soil and plant first. Over-fertilizing your sunflower can cause more growth in the foliage (stems and leaves) instead of flower growth. If your potting mix has compost and/or manure, it is unlikely that you will need to add extra fertilization.

If you feel the need to fertilize your sunflowers, make sure you get a fertilizer that has low nitrogen and is a balanced, slow-acting granular to make sure that you are just giving it the right amount of fertilization. Just the right amount of fertilizer can make the color of your flower heads become brighter and bolder. You can also opt to put some diluted fertilizer into your watering can for when you water your sunflower, but remember not to put too much of it.

Pruning

As beautiful and bright and cheery as they are, sunflowers won’t last forever. After a week or so, you’ll see some of the flower heads fading. When they do, you can remove them using a pair of scissors to snip them off.

Trimming your faded sunflower heads keeps your plant looking fresh, and in some cases, they may even encourage more growth. Make sure to trim the foliage (stems and leaves) in a way that will keep the size and shape you want. Trimming your sunflower plant regularly will also encourage the plant to develop more flowers.

Potted sunflowers in bloom vs. growing your own

Undoubtedly, planting and growing a sunflower from seedling to full plant can be challenging. You have to consider the weather, the soil, the kind of pot you have. Nevertheless, seeing it sprout those first few leaves can be quite rewarding.

If you aren’t sure, however, about growing a sunflower from scratch there is always the option of buying a potted one that is already about to bloom and caring for it.

If you opt to buy a potted sunflower in bloom already, make sure to check the number of plants in each pot and the number of buds per stem. Ideally, you want to buy a plant where the main flower is about to fully open by the time of purchase.

Make sure its soil is sufficiently moist and the stems are sturdy. Check the leaves also as wilting leaves give a sign that something is wrong. You might also want to inspect the sunflower in case there are aphids, slugs, and other pests.

How long does it take to grow a sunflower indoors?

Sunflowers can grow quite fast. Some of them can grow up to 12 feet in just 3 months. Indoor germination of sunflowers usually happens within 6-10 days. After that, you can enjoy continuous blooms for the rest of the summer by planting seeds every couple of weeks.