Planting & Landscaping

When to Sow Sunflowers: Growing Conditions and Planting

Sowing annual sunflowers is a great way to get your garden started and add some cheerful color. 

This article will discuss the different conditions you need for sowing sunflowers. When is the best time to plant them, and how to care for them once they're in the ground.

When should I sow sunflowers? The optimal planting time for sunflower seeds ranges from late spring until mid-summer, depending on your climate and your frost dates. Once planted, these plants thrive with plenty of sunshine. 

Sunflowers need at least six or more hours of direct sun to grow and flower prolifically.

While sunflowers can be planted in partial shade, the seeds will not germinate well or produce a good crop without enough sunlight. Sunflowers love the sun!

There are a great many varieties of sunflowers to choose from. They come in a wide range of colors and sizes, but most sunflowers are classified as either single stem sunflowers or branching sunflowers.

Single stem sunflowers have one large, central flower head. Branching varieties are bushier with many branches that grow in different directions, each ending in its own smaller seed head.

Sowing Sunflowers 


The seeds need well-drained soil with added compost to germinate properly and prevent rotting while they establish roots. The soil should also be loose and fine to allow the roots easy access for growth. 

If the soil is well prepared, added fertilizer will not be necessary during the growing season.

Sow your sunflower seeds every two to three weeks if you have a large garden or a long growing season. You can also extend the harvest by planting different varieties of sunflower seeds with staggered maturity dates.

Sunflowers require very little care once they're planted, but you should keep them well-watered during their first two or three weeks to ensure that germination is successful and seedlings get off to a good start. 

Once they are established and begin to grow, you only need to water the plants if rain doesn't fall for an extended time or your soil is very sandy and drains easily.

Start the seeds indoors in small pots if you are sowing before the last frost or plant directly into the ground if all chance of frost has passed and the ground has warmed.

  1. Plant the seeds in full sun and in well-drained soil about 6 in (15cm) apart. The further apart the seeds are planted, the larger the flower head will be.
  2. Bury each seed about 1 in (2.5cm) in depth.
  3. Water well and always keep the soil moist until the seeds germinate.
  4. If planted too close, thin them out.
  5. Once established, water daily if very hot or once or twice a week.
  6. Sunflowers reach maturity in 60 - 100 days, depending on the sunflower variety.

Sunflowers are mostly annuals and will die back at the first frost. 

Growing Sunflowers in Pots

Sunflowers growing in container

If your areas soil is poor, consider growing sunflowers in containers.

Sunflower pots can be placed outside after all chance of frost has passed, and there is no more danger of them being damaged by cold weather.

The dwarf sunflower is ideal for pots rather than taller varieties. They are bushier and have multiple stems with more than one bloom per plant.

Plant a few seeds per pot about two inches deep in rich, loamy potting soil and keep the pots in a sunny location.

Water daily until the sunflower seedling begins to sprout.

The pots should be spaced far enough apart to allow the flower heads to grow and develop without touching one another.

Allow the pot plants to dry out between waterings, but do not let them become too dry, or they will die.

Harvest Sunflower Seeds

harvesting-sunflower seeds

Sunflower seeds can be harvested as soon as they are pale yellow and the sunflower head has begun to open, or you can wait until all of the petals have fallen away. However, the edible seeds should still be green at this point for optimal flavor.

Leave a few sunflowers in place if you want them to return year after year, although they do not readily reseed themselves.

Harvest for next year's planting when they are brown and dry.
Sunflowers make good bird feeders, so leave some in place for the birds and squirrels who will enjoy snacking on them until they're gone.


Sunflowers are a great choice for your vegetable garden or flower bed because they offer lots of color and beauty without requiring too much attention from you.

In addition, they grow quickly, attract bees and other beneficial insects, help prevent soil erosion, and have edible flowers!

Another reason to plant sunflowers around your garden is that their large size helps protect your other plants from wind damage and the shade of their large leaves helps to keep soil temperatures cooler in warmer climates.

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