Sunflowers are so easy to grow, the birds often plant them for you for free! Pick a
sunny area where the plants will not shade other, lower-growing plants, such as against a fence or a wall. Sunflowers can leach a chemical into the soil that will stunt or prevent other items from growing. Keep your sunflowers in a separate, dedicated space, or practice good crop rotation to prevent chemical build-up. Your space needs to get at least 6 hours of sunlight or your sunflowers will lean to reach sun - this will delay flowering in favor of root and foliage development.
Sunflowers can be spaced fairly close together, and this will help them lean on each other when they are taller and a storm or high wind occurs. Staking can also be helpful for weaker stems or a plant on its own. Dwarf varieties don’t usually need staking unless they have thin stems.
Sunflower seeds can be broadcasted and pressed into the soil or you can start them 1/4” deep and 6-12” apart. Wait until sunflowers are at least 6” before thinning, removing the thinnest stems. Sunflowers don’t transplant very well, start them in the ground or pot that they will remain in. If potting, dwarf varieties are usually best. Ensure that your sunflowers are well watered, and only water at the base to avoid mildew. Sunflowers are hardy and can be fairly drought tolerant, but you will sacrifice blooms with a thirsty plant. If the leaves are droopy, it’s time to water! 1” of water per week will suffice in fall, 1-2” during the hottest summer months. A thick bunch of sunflowers may need watering in the center, so ensure even watering.
Sunflowers are easy to care for and have few pests. You may see holes in the leaves from leaf cutter bees, katydids and grasshoppers, or an occasional sharpshooter (aka leafhopper) but these will not affect the flowers in any way. Flowers can be affected by uneven watering (if only half of the flower opens) and deer. Deer can eat sunflower leaves and petals to nubs.
Harvesting and utilizing sunflowers
Helianthus annus varieties of sunflowers are completely edible from root to flower. You
can utilize the plants/leaves in salads, just be sure not to harvest too many leaves at once (no more than 1/3 in a harvest). Deadhead spent flowers to prolong blooming (above the first healthy leaf below the head), but leave the spent flowers in place if you want seeds.
Sunflower seeds are fairly easy to harvest and a delicious snack! Leave the spent flower on the stalk until it droops and the outer rim starts to pull back. If you can rub your thumb across the sunflower center and get some wiggle, you can cut the head. Use shears or a knife to cut the head off at the base (one hand to hold the head, the other to cut, if it’s large, consider having someone else hold the head during cutting). Put your sunflower head(s) on a baking tray with a lip and store them in a warm, dry area, such as an oven after use (not when it’s super hot!), and let it dry for a few days. When the heads are dried out more, you can rub your palm across the seed head to knock the seeds loose - do this over a bowl or the baking tray to catch the falling seeds. Once you have a few seeds out, it becomes easier to push them apart. When all of the seeds are removed from the head, it can be composted. The seeds need to go back into the warm, dry area or oven for another few days to harden. After the hardening/drying, gently press on your seeds. Little thin ones that are spongy can be discarded, as they are only a shell and no seed. Once the seeds are dry and harder, they can be bagged and used for snacks, or to start fresh sunflowers!