Top Tips for Sowing and Growing Sunflowers
There’s something undeniably cheerful about sunflowers. Whether you’re growing towering giants at the back of a border or compact varieties in pots, they’re one of the easiest and most rewarding plants to grow. With a little planning and care, you can enjoy bold blooms all summer long and even help wildlife later in the year.
Start Strong: Sowing Your Seeds
If you’re eager to get ahead, start your sunflower seeds indoors. Use small biodegradable pots, (old loo roll tubes or folded newspaper work perfectly) filled with peat-free compost. Place them on a sunny windowsill or in a greenhouse and keep the soil lightly moist. Seedlings usually appear within 14–21 days.
TOP TIP: Use biodegradable pots if starting indoors and plant them straight into the ground
To sow directly outside, wait until the risk of frost has passed, typically late May in the UK. Plant seeds about 12mm deep in well-drained soil, spacing them 30–45cm apart so they have room to grow without competing for nutrients.
TOP TIP: sow seeds on their side to reduce the risk of rotting.
Protect Young Plants
Tender sunflower seedlings are irresistible to slugs and snails. Without protection, they can disappear overnight.
An easy solution is to place a barrier around each plant. Cut the top and bottom off a plastic bottle and push it gently into the soil around the seedling. This creates a simple but effective barrier while the plant gets established.
Location Matters
Sunflowers follow the sun (heliotropism), so choose a bright, sunny, and sheltered spot in your garden. The more sunlight they get, the stronger and taller they’ll grow.
TOP TIP: Be patient when transplanting seeds raised indoors, wait until conditions are warm and stable
Water Wisely
Keep your sunflowers well-watered while they’re young and establishing roots. Once mature, they’re relatively drought-tolerant, but will need watering during prolonged dry spells, especially when flowering.
TOP TIP: Space plants to avoid competition for water and nutrients
Feed for Growth
Sunflowers are heavy feeders. In fact, they’re sometimes used in bioremediation because they draw nutrients from the soil.
To keep them flourishing, feed weekly with a nitrogen-rich fertiliser. This helps support strong stems and lush growth, especially in the early stages.
Support Tall Varieties
If you’re growing tall sunflowers, a little support goes a long way. Insert a sturdy cane into the soil near the plant and tie the stem loosely with soft twine. This prevents wind damage and keeps your sunflowers standing tall and proud.
Choose the Right Variety
Not all sunflowers are the same, so select what suits your space and needs:
Tall varieties add height to borders such as ProCut (Pro-Cut) series
Branching types are multi-headed so perfect for cutting and creating bouquets, such as sunflower Vanilla Ice
Beyond Summer
Leave the flower heads to develop seeds in autumn and winter. They’ll provide a valuable food source for birds and other wildlife. Once the plant has finished, cut and dry the stems to use in homemade bug hotels, supporting beneficial insects in your garden.