Here are some tips for growing sunflowers from seeds:
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When to plantSow seeds in late April or early May directly into the ground, or in pots in late March or April. You can also start seeds indoors a few weeks before the last expected frost.
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How to plantPlant seeds about 1 inch deep and 6 inches apart for shorter varieties, or a foot apart for taller varieties. You can also plant two seeds per hole to increase your chances of germination.
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Where to plantPlace pots in a warm location with lots of light but out of direct sunlight, such as a sunny windowsill or greenhouse. Cover with a clear plastic bag or mini cover to protect from slugs and snails. Once seedlings have emerged, remove the cover.
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How to careWater regularly until the seeds sprout, and keep the soil moist while they germinate. After they're established, water every few days during dry spells to encourage strong roots. You can also weed the area so seedlings don't have to compete for nutrients and water.
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When to harden offOnce seedlings are a few inches tall and have their first set of leaves, gradually expose them to outdoor conditions for about two to three weeks. Then, you can plant them outdoors.
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How to thinWhen seedlings reach 6 inches tall, thin them so the strongest plants are about 12 inches apart.
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How to feedBefore planting, you can spread compost or well-rotted manure over the soil. Once the plants are young, you can feed them weekly with liquid seaweed or nettle feed to boost growth. When flowers form, you can switch to a potassium-rich feed like comfrey or tomato feed to encourage large blooms.
Depending on the variety, sunflowers can take 80 to 120 days to bloom from the time you plant the seeds. You can also try succession planting, which involves sowing a new row of seeds every two to three weeks in the spring to ensure a continuous supply of blooms until the first frost.