When to Plant Sunflower Seeds – Planting Guide 2024

Save for later!

Large, bright, and joyful, there’s something about sunflowers that brings an instant smile to one’s face. These voluminous flowers are at home in just about every garden and while they are nice to look at, they are also great at attracting the attention of those important pollinators, bees.

Find out when to plant sunflower seeds so you can add some brightness to your garden. Get ready to plant your sunflower seeds so that you have towering giants looking over your garden.

When to plant sunflower seeds? Plant sunflower seeds in the spring, once the soil is properly warmed up. This can range from March to July, depending on where you live and how long your summer growing season lasts. Once planted, give your seedlings water, but once they grow larger, drop to watering just once per week to create strong roots.

As your sunflowers grow, you may need to stake them to give them extra support. Furthermore, if you don’t want birds or squirrels to get them, you may have to put a mesh covering over the seeds. In 80 to 95 days, you will have gorgeous, vibrant sunflowers in your garden.

Planting Sunflower in Different Climates

Tropical Climate

Sometimes, sunflowers will be ok in a tropical climate. The biggest risk is fungal diseases as the humid weather can bring too much moisture.

Dry Climate

While sunflowers love the heat of a dry climate, they also need water. If you plan on planting in a dry climate, you need to be vigilant about giving your sunflowers enough water for their roots to thrive.

Temperate Climate

The warm summers of a temperate climate do well with sunflowers. Plant in early spring, after the risk of frost is gone, and you will have lovely sunflowers in the summer.

Continental Climate

Sunflowers do really well with the heat of a continental climate’s summer. Just wait until the soil really warms up, but don’t worry as you can plant as late as early July.

Polar Climate

Unfortunately, sunflowers will not grow in a polar climate as it is too cold.

Choosing Sunflower Seeds

There are many varieties of sunflowers to choose from, and they usually depend on how tall you want these flowers to be.

For those that love large, ostentatious blooms, check out the Mammoth variety. These flowers grow to be 12 feet tall and make for an excellent, natural bird feeder.

If you want a variety of colors, try the Autumn Beauty variety. These seeds produce colors including bronze, light brown, and yellow.

Finally, if you have a smaller space but don’t want to miss out on sunflowers, try the Teddy Bear variety. They grow to be just 2 to 3 feet tall, and even work well in containers.

One interesting fact many people have discovered is that the seeds in birdfeed make for excellent sunflowers. There have been many times where people have put out a mixed birdseed, only to find sunflowers popping up underneath the feeder from spilled seeds.

How to Plant Sunflower Seeds

Sunflowers are pretty easy to grow, as long as you remember that less is more. It’s actually better to direct sow sunflower seeds into your garden. They do not like their roots disturbed so it’s better to not plant them inside and then transfer to the garden.

As their name suggests, sunflowers prefer full sun so make sure you plant them in a bright, sunny area of your garden. Furthermore, they like warmth. You want to plant sunflower seeds when there is no more risk of a spring frost, and when the soil is above 50 degrees Fahrenheit.

If you’re a bit confused about when to plant sunflower seeds, you actually have a large window.

In southern parts of the US, you want to plant seeds between March and April. However, in other, cooler areas you can plant seeds between April and July.

While sunflowers can grow in many different types of soil, they do like it to be loose and not too compact. This is because, in order to support their towering frames, sunflowers have a very deep root system.

Make sure the soil can drain properly as you don’t want water to pool on the surface. This can cause the plant to rot.

In order to create their lofty height, sunflowers need plenty of nutrients. Ensure the soil is rich with organic matter such as manure or compost. You can also add flower-specific fertilizer to the soil.

Once your soil is properly prepared, you can start planting seeds. Dig holes that are 1 to 1 ½ inches deep, and try to space the flowers at least 6 inches apart to allow for proper root systems.

When placing your seeds, you can also add a bit of fertilizer to the hole in order to give your seedling the best chance possible.

Finally, space your seed planting by a few weeks. Each week, plant a few more seeds so that you will have lovely blooms for all of late summer.

How to Water Sunflowers  

Sunflowers need plenty of water but they have different preferences than other flowers. You should only water one to two times a week, and when you do, you should water liberally.

This way of watering will encourage your sunflower roots to go deep and become stronger.

When you have smaller sunflower plants, you can water a bit more frequently. However, you want to water around the root zone, which is about 3 to 4 inches away from the plant.

If your summer is exceptionally hot, you can water more frequently, especially as the stem becomes taller. Without proper water and nutrients, sunflower stems will topple.

How to Grow Sunflowers

Depending on the variety you plant, sunflowers can need a bit of extra support. There are many giant varieties that can topple over in a windstorm.

Don’t be afraid to stake your sunflowers to give them this support. Take a long pole, such as a bamboo stake, and place it next to your sunflower stem.

Instead of tying string around both parts, make sure the string is wound a bit and the knot is next to the bamboo stake. Otherwise, the string will cut into the sunflower stem and damage it.

As the summer progresses, you may want to think about giving your sunflower more nutrients. While you don’t want the fertilizer to be near the base of the plant, you can add it to the soil when it is 12 to 18 inches away from the stem.

How long do sunflowers take to grow?

Sunflowers are large flowers and so take quite a bit of time to actually grow and flower. After planting them, expect your sunflowers to really pop out between 80 and 95 days.

Because of this long growing season, sunflowers are late-summer flowers. You won’t see them in your garden until August.

How to cut sunflowers?

While it’s lovely to have sunflowers grow in your garden, it’s equally special to have them light up your living room. Sunflowers are great for making bouquets.

If you decide to go this route, cut your sunflowers before the main bud has opened. This will hopefully encourage side blooms to occur.

Try to cut your sunflowers in the early morning when they have morning moisture in them. If you cut them in the afternoon, they may be too dried out and will start to droop right away.

Find a tall vase for your sunflowers. This allows the long stems to receive enough water and a chance for the heavy heads of the sunflowers to rest.

Change the water every other day and your sunflowers should last for at least a week inside.

How to harvest sunflower seeds?

Sunflowers are amazing in that you can actually harvest the seeds, either for snacking or to plant in your garden the following year.

Be sure to leave your sunflowers out, even after the blooms start to die. The seeds should look loose and plump.

If you are waiting to eat your sunflower seeds, then you may need to protect the flower from birds. Simply place a layer of cheesecloth and tie a band around the flower head in order to keep out unwanted birds from having a little snack.  

Cut the head of the sunflower off and place on a flat surface. You can put a towel down underneath to catch any stray seeds.

Simply take your hand and gently rub it over the seeds. This should be enough friction to loosen them. You can also pull them or use a fork.

Store the sunflower seeds in a cool, dark place so they will be ready for planting the next spring.

For those that want to roast their seeds, soak them overnight in salted water, and then strain them and leave them to dry.

Place them in the oven at 300 degrees Fahrenheit for 25 to 35 minutes, and be sure to stir them frequently. Once roasted, mix them with a bit of olive oil and salt, and enjoy.


Sunflowers scream sunshine. They are glorious, towering marvels of nature and are sure to brighten up any garden. Plant them in full sun, be patient, and you will be rewarded in August with a wonderful end to summer.

Related Articles:

Save for later!

Leave a Comment