Zinnia flowers

How to sow zinnia seeds outdoors

We show you how sow zinnias outdoors in the warmth of late spring and early summer.

Do it:

May, Jun

Takes just:

30 minutes

At its best:

Jul, Aug, Sep, Oct

If you're looking to grow flowers for vibrant summer colour, look no further than zinnias. With so many zinnia varieties available, it's no wonder they're such a popular cut flower.

Zinnias can be sown indoors from February to April, but can also be sown outside in May. Just choose a fertile, weed-free area, whether it's a gap in a border or a patch of bare soil, and get sowing.

Once they're in bloom you can expect a profuse display of summer colour up until the first autumn frosts.

Discover how to sow zinnia seeds outdoors with the help of our four simple steps, below.

You will need

  • Rake
  • String
  • Zinnia seeds


Sow in fertile soil that is free of weeds and rake it to a fine, crumbly consistency. Use a taut string to make a straight line and take out a shallow drill.

Sow the seeds along the drill, making sure they are 10-15cm apart. Use your hand to fill the drill with soil, lightly covering the seeds.

Water the seeds well, adding a label to the area so you know what you're growing. Keep the soil most, but not saturated, as seedlings begin to grow, and cover with a cloche.

If you're looking to grow flowers for vibrant summer colour, look no further than zinnias.

When seedlings have formed a couple of pairs of leaves, thin them to around 30cm apart. Water frequently in dry weather and keep weed-free.


Zinnias for pollinators

Zinnias are attractive to pollinating insects, particularly hoverflies. To ensure they can reach the pollen and nectar, be sure to grow single-flowered varieties that don't block pollinator access. 

Discover more ideas and inspiration

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10 colourful zinnias to grow

Flower seeds to sow in April

How to grow dahlias from seed

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