Sunflowers are an iconic late summer, early fall bloom that everyone can recognize. They can be cut to decorate your home or planted to add color and variety to landscaping, and sunflower seeds can be harvested as a tasty snack. No matter the reason you’re in love with these flowers, it’s common to wonder if you can plant them in late summer and still enjoy blooms.
As with almost any question related to gardening, it depends. It depends on which USDA zone you’re located in, the variety of sunflower you wish to plant, and just how late in the summer you’re thinking of growing them. In zones 8 and higher, you’ll likely have success with a late summer sowing of sunflower seeds. However, they may grow shorter and produce fewer blooms because of the shorter days and decreased sunlight. You’ll also want to keep an eye out for early frosts. Frost will burn or kill your sunflower plants and result in no blooms at all. You can either cut the flowers and bring them indoors or try to cover them on chillier nights. To avoid any disasters, it’s best to begin sowing sunflower seeds no later than mid to late August in these zones.
Sunflowers take between 55 and 70 days between sowing and producing flowers. As long as you have that many days or more between now and the end of your growing season (first frost date), you should be good to go to plant late-season sunflowers.
While it’s safe to sow sunflower seeds even in late summer (in zones 8 and higher) to get the most out of sunflowers and their striking blooms, here’s what you should do.
The best way to get the most out of any garden is to plan, plan, plan. This means gathering seeds, drawing out a garden map, and planning what will go where and when. This way, when the time comes to plant, you’re not rushing around trying to get everything ready –– or worse, giving up. Buy a dedicated calendar for gardening and markdown when your sunflowers need to be directly sown into the ground.
If you plant your dedicated sunflower bed completely in the first week of planting season, you’ll have all your sunflowers bloom and die at once. To prolong the blooming phase and the amount of enjoyment you’ll get out of the bloom, try succession planting. This means you plant a certain amount of flowers one week, then another the next, and so on. Then you’ll get a new group of flowers blooming every week, and your garden will have more fall colors for weeks.
While many plants like tomatoes or zucchini don’t mind getting transplanting from seed starting trays, sunflowers don’t like their roots to be disturbed. You might have some success in starting sunflowers indoors, but to get the most out of them and to achieve healthy and big blooms, direct sow.
Sunflowers are hungry, hungry hippos. You’ll want to fertilize them more often than you might be used to with other flowering plants. Since they grow so tall, so fast, and have to support large blooms, they need a lot of food to be sturdy and healthy. Use either a slow release fertilizer early in the season or fertilize the plants with organic compost or liquid fertilizer every two weeks during their big growing season.
Avoid high wind areas
Sunflowers get notoriously tall and have famously big flowers. Unfortunately, this combination can end in disaster if the sunflowers are planted where high winds could knock them over. If you can, plant sunflowers near a fence or beside a shed where they’ll sheltered from the wind and will be less likely to topple over.
Plant sunflowers about 6 inches apart and 1 to 1.5 inches deep. When planted, supply the seeds with plenty of fertilizer upfront, then wait to fertilize again until the plant has become established. It’s then you’ll also want to begin watering deeply to encourage deep, strong roots. As the plant grows taller and taller, you might want to provide them with additional support using bamboo stakes. The stakes are strong enough to support the flower but won’t distract from the plant’s beauty.
Whether you want them to decorate your table or you love snacking on sunflower seeds, these plants are a favorite among novice and veteran gardeners. Once you try them yourself, it’s easy to see why!
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