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How to grow sunflowers
Sunflowers are annual plants and no plant says summer like a sunflower. Their vibrant bright yellow blooms is like sunshine on a stalk. Growing sunflower plants is easy because they are tough and will grow in any almost kind of soil as long as it is not waterlogged. They’re also heat tolerant, pest resistant and fast growing. Sunflowers are usually bright yellow but you can get red or brown that ripen just as well into a head filled with seed.
What’s the history of Sunflowers?
The modern sunflower can trace their ancestry to plants found in archeological digs dating from 3,000 BC. Sunflowers were first purposely cultivated by Native Americans as a source of medicine, fiber, seeds, and oil.
Botanical Name: Helianthus annuus
Common Name: Sunflower
Flowering Time: Most sunflower varieties bloom for several weeks
You can use sunflowers as focal cut flowers, leave them on the stalk for a gorgeous outdoor display in your garden, or harvest and eat their seeds or just leave the heads alone for the birds. Many sunflower varieties attract bees and birds who dine on sunflower pollen and seeds, making them a great choice for helping wildlife.
When to Plant and Sunflower Care
- Sunflowers worship the sun so grow best in spots that get six to eight hours of direct sun per day.
- They have long tap roots that need to go several feet into the ground, so sunflower plants prefer loose, well-drained, somewhat alkaline soil with a pH of 6.0 to 7.5.
- Cover seeds and keep watered until seeds sprout in 7 to 10 days.
- When first true leaves appear (the second set of leaves); thin plants.
How long does it take for sunflowers to grow?
- From the time you put the seed in the soil to bloom ranges between 80 and 120 days, depending on the variety. For continuous blooms, stagger your planting, sowing a new row of seeds every two to three weeks, which will keep you supplied with flowers until the first frost.
- Sunflowers are heavy feeders, while they don’t need fertilizer, they’ll flower best in nutrient-rich soil that has had compost dug into it.
- Growing sunflowers in pots is possible if you choose a smaller variety, just be sure the pot is deep enough to accommodate their tap root.
How to Plant Sunflower Seeds
Growing sunflower plants is easiest if you grow them from seed sown directly into the ground but using small compostable pots are fine as you can get started early in a green house and plant out without disturbing the all important tap root. Another bonus for growing sunflowers from seed is choice! There are more varieties of sunflowers available to you if you grow from seed. Please check out our recommendations below.
If planting directly outdoors, just make sure you plant seeds after the danger of spring frost has passed. This will be between March and May, depending on where you live.
Caring for Sunflowers
Don’t spoil sunflowers by giving them too much water, they need to be encouraged to grow a long tap root to keep them from toppling over. Once your plant is established, water just sufficiently to encourage the plant to grow deep roots but more often if the weather is very dry or very hot.
Tall varieties may need extra support so they don’t fall under the weight of their heavy blooms. Bamboo poles or other types of long wood stakes work well for this purpose. I like to use natural twine that breaks down when the season is over.
Pests and Diseases
Fungal diseases like downy mildew, rust and powdery mildew can infect sunflower plants. Spray infected leaves with a general garden fungicide. Downy mildew is most likely to occur on cool damp nights and warm humid days. It spreads by means of tiny spores carried to plants and soil by wind and rain or even by garden tools.
Harvest: Cutting Sunflowers for Bouquets
Cut flowers early in the morning, before heat has stressed the plants. Harvesting flowers in the middle of a hot day can cause the flowers to wilt. The blooms will naturally close up at night.
For the sunflower varieties that consist of multiple stems, cutting the main stem of the plant before its bud has opened will encourage the plant to make even more blooms on the sides of the stem.
Cut sunflowers will last about a week in water at room temperature.
There are many types of sunflowers, ranging from giants to dwarfs. Here are some of our favorites:
- Mexican sunflower
- Mammoth sunflower
- Red sunflowers
- White sunflowers
- Velvet queen sunflower
- Autumn Beauty sunflower
- Lemon queen sunflower
- Chocolate cherry sunflower
Organically grown ‘Russian Mammoth’ is the traditional super giant sunflower, that can grow to more than 12 feet tall with flower heads bigger than dinner plates. Its seeds are good for harvesting and is great for growing with kids.
Double dwarf ‘Teddy Bear’ is a tiny variety it’s great in pots and small gardens. Its soft fluffy gold blossoms make excellent and unusual cut flowers.
Unusual Sunflowers to grow:
- Sunflower seeds, leaves and stems emit substances that inhibit the growth of certain other plants. They should be separated from potatoes and beans.
- Some varieties of sunflowers can get very tall and shade other plants, so don’t plant sun-loving companion plants too close.
- Tall sunflower varieties of sunflowers work best as a screen, at the back of a border bed, or along a fence.
- Shorter sunflower varieties can be grown in the middle of a border or in pots.
Handy sunflowers varieties for privacy or screening:
Sunflowers are a great tempory choice for boundary screening