Sunflowers they do take a bit of time to grow into their full height, especially if they’re of a particularly large varietal. Sunflowers are more like trees than flowers when fully grown: they stand tall and have a woody, almost trunk-like stem. The big, bright yellow flowers come in many sizes, with the giant sunflower able to shoot up over 20 feet. To grow sunflowers, sow the seeds directly into the soil. As the seeds are also tasty treats for birds and other varmint, you should cover the planted seeds with something, such as a screen, until they start to germinate.
You also can start sunflowers in peat pots indoors two to three weeks before the last frost date for your area. If you start your sunflowers in peat pots indoors, plant one or two seeds per pot and thin to a single plant before you transfer them outside in your garden. Something to keep in mind before you plant your sunflowers in your yard is that their blooms will always face east. When planting individual flowers, make sure to put the seedlings in a sunny spot; the spacing of your sunflowers depends on the size you are planting. For the giants, space the seeds or your peat pot plants 3 feet apart in rows 3 to 4 feet apart. For the regular size, space 2 feet apart in rows 3 feet apart. The miniature flowers can be spaced 1 foot apart in rows 3 feet apart. If you are planting different sized varieties, make sure to plant the tall ones in the back with the smaller varieties to the front as a border.
Sunflowers need to be planted in rich soils, especially the giant variety, as they can be easily uprooted in loose or sandy soil. When fertilizing your garden, make sure to include the sunflowers as well: apply extra phosphorus and potassium when the bud begins to develop. Sunflowers are low-maintenance and don't require a lot of water, but you must be patient: you won't see growth right away. Depending on how deeply you planted the seed, it will take about three weeks before you see growth, with a mammoth sunflower taking as long as three months to grow to its full size.