Zinnia flowers

How to sow zinnia seeds outdoors

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

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
At its best
At its best

Plant is not at its best in January

Plant is not at its best in February

Plant is not at its best in March

Plant is not at its best in April

Plant is not at its best in May

Plant is not at its best in June

Plant is at its best in July

Plant is at its best in August

Plant is at its best in September

Plant is at its best in October

Plant is not at its best in November

Plant is not at its best in December

To do
To do

Do not To do in January

Do not To do in February

Do not To do in March

Do not To do in April

Do To do in May

Do To do in June

Do not To do in July

Do not To do in August

Do not To do in September

Do not To do in October

Do not To do in November

Do not To do in December

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.

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

You will need

  • Rake
  • String
  • Zinnia seeds
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Total time:

Step 1

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.

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Step 2

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.

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Step 3

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.

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Step 4

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.

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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.