Picture: Sunflowers Growing From Seeds In Container
The sunflower is the most popular oilseed crop in Europe and North America, and the crop originated and was domesticated during the first millennium B.C. Sunflowers are believed to have been grown by American Indians in Arizona and New Mexico as far back as 3000 BC, and were used in many ways — seeds were ground into flour for cakes and bread, oil was squeezed from the seed for bread making, and non-food uses included dye for textiles and body painting. Sunflowers were taken to Europe by Spanish explorers around 1500, where the plant became widespread throughout Western Europe for ornamental and medicinal purposes.
The common sunflower (Helianthus annuus) is a species of large annual forb of the daisy family Asteraceae, harvested for its edible oily seeds. The plant has an erect rough-hairy stem reaching typical heights of 3 metres, and the tallest sunflower on record achieved 10.9 m (35 ft 9 in). The attractive flower heads are 7.5–15 cm wide in wild specimens and often 30 cm or more in cultivated types. The disk flowers are brown, yellow, or purple, while the petal-like ray flowers are yellow. What most people call a single “flower” is actually a remarkable composite — each flowerhead is made up of up to two thousand florets, packed full of nectar and a great treat for bees.
One of the most fascinating things about sunflowers is hidden in their seeds. Generally, each floret is oriented toward the next by approximately the golden angle of 137.5°, producing a pattern of interconnecting spirals where the number of left and right spirals are successive Fibonacci numbers. Typically, there are 39 spirals in one direction and 55 in the other, and this pattern produces the most efficient packing of seeds mathematically possible within the flower head. Mathematician Alan Turing, famous for cracking the Enigma Code during World War II, later became fascinated with these mathematical patterns found in plant stems, leaves, and seeds — a study known as phyllotaxis.
Sunflowers carry deep symbolic and cultural meaning across civilisations. Vincent van Gogh famously painted twelve canvases of sunflowers, seven of which he used to decorate his home in Arles. Sunflowers are also the emblem of the third year of marriage — their strong stems symbolise the foundation of a relationship, while their sunny disposition represents the warmth shared between lovers. For the Hopi tribe, a big sunflower bloom meant there would be a good harvest year, while the Teton Dakota tribe believed that when sunflowers were tall and blooming, it would be a good hunting season for buffalo.
The common sunflower is valuable from an economic as well as an ornamental point of view — leaves are used as fodder, flowers yield a yellow dye, and seeds contain oil used for food. The sweet yellow oil obtained by compression of the seeds is considered equal to olive or almond oil for table use. Beyond food, sunflowers have a remarkable ability to absorb toxins, including toxic metals and radiation. Following nuclear disasters such as Chernobyl and Fukushima, scientists planted millions of sunflowers to help the land recover — in scientific terms, they are “hyperaccumulators.”
Picture: Sunflower Seeds
How To Grow Sunflowers From Seeds (17 Steps)
- Choose your variety — there are hundreds of varieties, including dwarf types for containers and tall branching types perfect for cut flowers, with colours ranging from pale lemon yellow to orange, pink, burgundy, and bright yellow.
- Pick the right time — sow sunflower seeds directly into the garden after the danger of spring frost has passed, anytime after soils have warmed to at least 50°F (10°C).
- Choose a sunny spot — sunflowers need at least 6 to 8 hours of direct sun per day, no exceptions.
- Find a sheltered location — shelter from strong winds — for example, along a fence or near a building — helps sunflowers as they mature.
- Prepare the soil — prepare the existing soil by mixing in all-purpose garden soil to improve drainage and nutrients before planting.
- Direct sow whenever possible — direct sowing is almost always the right choice for sunflowers, as they dislike root disturbance and establish best when sown directly where they’ll grow to maturity.
- Plant at the right depth — plant sunflower seeds 1 to 2 inches deep after the last threat of frost.
- Space seeds correctly — space seeds 6 inches apart for smaller varieties and 12 inches apart for taller varieties, with rows spaced 2 to 3 feet apart.
- Water at planting — water seeds at the time of planting and regularly throughout the growing season.
- Protect from pests — freshly sown sunflower seeds are a target for squirrels and birds; scatter a little cayenne pepper around the planting area or cover with lightweight row cover until seeds have germinated.
- Thin out seedlings — once seedlings reach 6 inches tall, thin to the strongest plant per hole by snipping the weaker seedling at soil level — don’t pull, as the roots are already intertwined with their neighbours.
- Control weeds early — sunflowers can only outcompete weeds once they start to mature, so weed control is extremely important in the early stages of growth. You can control weeds by tilling, hoeing, hand-pulling, or applying mulch around the plants.
- Fertilise wisely — once the second set of leaves have appeared, a slow-release all-purpose fertilizer can be applied directly to the plants to speed up growth and produce larger flowers.
- Water deeply as they grow — once established, water deeply and infrequently to encourage deep rooting, which makes plants sturdier and more drought-tolerant. Aim for 1 inch of water per week, more in hot weather.
- Stake tall varieties — stake sunflowers if they have multiple branches or heavy flower heads, placing a sturdy stake 3 inches from the plant stem and tying the stem to it loosely with twine.
- Try succession planting — consider succession planting to have sunflowers blooming throughout the entire growing season, accomplished by planting the same variety every two to three weeks or planting different varieties with different maturity dates.
- Harvest at the right time — watch for when the flower heads start to hang down, as this signals the seeds are full size and ready to harvest. Cut the sunflower head and let it hang upside down until the seeds are completely dry.