Do You Know How Late Can You Plant Sunflowers?

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Last Updated on March 24, 2022 by Griselda M.

If you are already late to the party, you could be wondering how late can you plant sunflowers and still get a good harvest out of them?

Sunflowers are some of the most iconic late summer, early fall flowers that everyone never misses.  You can harvest them to decorate your home or plant them to add color and variety to your landscaping.

As if that’s not enough, sunflower seeds are a tasty and healthy snack. No wonder everyone is in love with these flowers and can plant them in late summer and still enjoy blooms.

Sunflowers grow fast; they are attractive to pollinators and downright beautiful. If you wonder how late you can plant these flowers, let’s learn how and when to do that.

When Is The Best Time To Plant These Flowers?

The best time to plant sunflowers is after the last frost date in late spring. Even a light frost can damage your flowers seriously.

Sow your seeds between April and July to have them bloom in the middle of summer and early fall. When sown, these flowers take as long as 7 to 10 days to germinate. They also take about 55 to 75 days before they start to bloom.

Remember, if you are planting them for bloom, plant them during the recommended period so the flowers will flourish before the early frost in fall.

When Is The Best Time To Plant These Flowers

How Late Can You Plant Sunflowers?

The answer to this question varies.

  • It depends on where you plan to sow the seeds.
  • The time limit for planting them in the garden is not the same as the time limit for growing them in a container.
  • The time limit also varies according to the various locations.

When Is t Too Late To Plant Sunflowers In The Garden?

If you do not plant your sunflowers before July, you might be wondering if it is too late to sow the seeds in your garden.  You can go ahead and sow the seeds any time until mid-August.

After mid-August, it is best to keep your seeds for the next planting season because they will not flower due to the frost freezing them.

It takes the flowers an average of at least 2 months to bloom, so if they are planted in late August, the blooms risk being destroyed by the early frost in October before they can mature.

How Late Can You Plant These Flowers In A Container?

Sunflowers can grow in a container and thrive the same way they do in the garden. If you plan to plant a few sunflowers for decorating indoors during the fall, you should consider the containers.

Growing these flowers in a container makes it possible to bring them inside when frost sets in.  Therefore, sow the seeds in a container in late August.  Plant them in large pots with fertile soil to facilitate their immense growth.  Water the flowers occasionally and keep them in a space that allows sunlight to penetrate.

How late to plant sunflowers according to different zones

You are right, every zone has its early or late planting season, and we cannot generalize them all as though they are one.

The time limit to plant sunflowers in each area depends on the climate of that region.  In the frost-free tropical and subtropical areas, you can plant sunflowers all through the year.

Can You Plant Sunflowers In The Fall?

If you are planting in the garden, your sunflowers cannot thrive in the fall season.  This flower does not withstand the light or heavy frost.  Therefore, growing it outside in the fall is not possible.

However, if you want to grow your sunflower in pots during fall, it is possible as you will move them indoors when the weather changes.  When you move your pots inside, keep them close to a window that allows plenty of light to keep your plant growing.

Sow Right Seeds – Mammoth Sunflower Seeds to Plant and Grow Giant Sun Flowers

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How To Keep Your Sunflowers Healthy In Mid-Late August

Plant Healthy Seeds

Since you are already planting late, you don’t want to risk using unhealthy seeds. They can be a sure downfall to your getting a good harvest.  Sow healthy seeds within 6 inches apart from each other and an inch deep into the soil.  Spread a net over the place you have planted to prevent the birds from picking out your seeds before they sprout.

Plant On Fertile Ground

Make sure the soil you use is rich and fertile, so the seeds germinate fast.  Since you are planting late, you should not allow any chances of late germination.

If your soil needs a boost, use a slow-release fertilizer.  Please do not add any fertilizer to fertile soil as you will cause it to produce excess Nitrogen in the ground causing the stems to break. Instead of fertilizers, you can opt to add compost or old manure for best results.

Water Occasionally

Sunflowers can thrive without water, but it is necessary to water the seedlings daily around the roots. The seedling needs to stay hydrated not to dry off and die early in their journey.

Water mature sunflowers once every week. Do not overwater the soil because the leaves will turn yellow when the soil is too wet.  Drenched soil will also cause fungal infections to your flower that will prevent them from blooming.

Water Occasionally

Read more about What Do Brown Spots On Sunflower Leaves Mean?

Protect From Other Pests

Besides the birds that love to peck on sunflowers, other common pests include deer, squirrels, slug, and snails.  Protect your sunflowers from these pests to grow healthy flowers.


Sunflowers are beautiful flowers that we all want to grow. They bring a warm glow to our homes that we cannot even begin to fathom.

These flowers can be planted as late as mid-August in the garden but after that, keep your seeds for next year’s planting season. However, all is not lost if you want a boom for the dark fall season.  Go for a container of sunflower to bring indoors when the temperatures dip, allowing it to continue its growth there.

Growing sunflowers has never been this fun.  Happy gardening, and may the giant bright sunflower bring a smile to your face!

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