See our competition page/link for rules
Grow in Full Sun
Sunflowers need a lot of sun! The ideal location provides 6-8 hours of sun a day in a sheltered location so there’s low risk of wind or storm damage.
Grow in Ground
It’s all about root space! Growing sunflowers in the ground in rich, well-draining soil, free of rocks or tree roots, is key. Any obstacles in the soil will inhibit root (and plant) growth.
You can grow sunflowers in containers, but for the tallest category.
Well Drained Soil
Sunflowers are hungry plants, needing a lot of nutrients to grow those big flowers and produce thousands of seeds. Provide nice, loamy soil, if needed add loads of homemade compost to the soil to gradually build it up.
Most sunflowers can grow anywhere from 6 to 36-inches apart, but, when you want to grow giants, it’s best to allow as much room as you can.
Allow space for the roots to spread several feet in any direction, both horizontally and down into the ground.
Space Provide A Wind Break
The taller the sunflower, the more vulnerable it is to wind breakage or snapping under the weight of a climbing squirrel.
If you can, grow your sunflowers near a tall fence or wall, out of direct wind.
Mulch After Sowing
While sunflowers do not like swampy soil, neither will they tolerate drying out. An inch of two of compost or finely chopped bark mulch will help keep moisture in and gradually decompose to amend your soil.
If you are going to add any support stakes or tall cages, it’s best to add them when the sunflower is young and the roots are small.
The older sunflowers get, the fussier they get, so any disruptions later on should be avoided.
The number one killer of sunflowers is pests! The problem begins after sowing seeds. Birds, squirrels, mice, and all their distant cousins smell those seeds from far and wide and come ready for a snack.
At seedling stage, birds fine them irresistible. Cutworms can also take them down.
Place covers over germinating sunflower seeds and keep them protected until they are several inches tall at least.
On the flip side, the hungry critters return when the flower heads start turning to seed. Use bags or netting to protect the flower heads. Or let them dine.
Besides choosing super seeds, proven to grow big and tall, fertilizer is key to maximizing the height.
Dig shallow trenches in circles around the plant—about 12 to 18-inches out, and add liquid fertilizer there, to reach more of the roots.
It’s easy to over-do fertilizer, hurting both the plant and the soil so follow the instructions on any product you use. More is not more with plants: they can only absorb what they need when they need it under the right conditions.
Sunflowers do not like to dry out—or get waterlogged—and that means keeping the water nice and even, right through the growing season.
As the plant gets tall and starts to bud, you may notice that sunflowers start needing more water. You may need to increase your watering routine, especially during dry spells and heat waves, which tend to go together. If you’re worried about over or under watering, a moisture meter is your best friend.
Pinch Side Shoots
This is an extra tip if you really want height beyond anything else. To keep your sunflower putting all its energy toward height, you can remove any extra side shoots, and grow just single stalk with a flower on top. You will end up with a giant bean pole, but, if this is what makes you win the tallest category, so be it.