The classic, yellow, single-stem sunflower usually grow quickly and easily. Sunrich and Pro Cut are good beginner options. [2] X Research source Branching varieties produce many flowers per seed, but most grow more slowly. If you plan to cut the flowers, get a pollen-free or low-pollen variety such as Cherry Rose to avoid a sticky mess. [3] X Research source Larger varieties such as Mammoth Gray Stripe and Humongous tend to produce tastier seeds, and can provide support for climbing plants. [4] X Research source [5] X Research source (Some smaller varieties produce birdseed-quality seeds. )
Short-day: These need long nights to trigger flowering. Plant them toward the end of summer (or start them indoors in mid-spring). Long-day: These bloom during the middle of summer. Day-neutral varieties can be planted any time during the growing season. Plan ahead based on the expected flowering time. Most single-stem sunflowers bloom 60 days after planting from seed, while branched sunflowers bloom after 90 days. [7] X Research source
If the soil is poor, mix in 3 or 4 inches (7. 5–10cm) of compost into the topsoil. [10] X Research source
Plant extra seeds if you have the space. You may thin them later, or lose some seeds to pests.
Plant the seeds 6 inches (15 cm) apart for smaller, bouquet-sized flowers, or 9" (23) cm + for larger blooms. [13] X Research source If your sunflower’s max height is above 5 ft (1. 5m), plant them at least 1 ft (0. 3m) apart. Giant varieties may need 2 ft (0. 6m) of space. [14] X Research source Most branching varieties need 18" (46 cm) of space. [15] X Research source
If the leaves look normal except for a striking yellow bleached color, this is a bacterial infection instead. Keeping soil dry will help here as well, and the plant will usually be fine. If the leaf looks yellow but still has green veins, the problem is most likely a mineral deficiency. It can be tricky to pinpoint the exact problem, but diluted fertilizer may work. Be aware that it’s normal for sunflowers to lose their first set of leaves once they begin growing in earnest. Don’t worry if the bottom leaves yellow and drop, but the rest of the leaves are fine.
Try not to get the blooms wet, as this can damage them. [21] X Research source
Cut flowers in the early morning or early evening. Use a clean knife or shears. Strip off any leaves that would be below the water line. Place in water immediately.
Most sunflowers will produce many more seeds if you attract bees to your garden to pollinate them.
Store seeds in a cloth bag to allow air to circulate. This helps prevent mold.
