Synonymous with cheery subject and prairie vistas , the sunflower ( Helianthus annuus ) develop chop-chop , germinating , efflorescence and dying within one uprise season . This annual flora acquire in any fertile grunge that is neutral or alkaline in pH and remain lovesome , moist and well draining . Many variety of sunflower exist with different efflorescence colouration , sizes and ripe plant heights .

Germination

When covered with 1/4- to 1/2 - in of moist soil , the sunflower seed withdraw five to 12 days to germinate after planted . Germination go on in soil temperatures as low as 39 degree Fahrenheit but hasten considerably when soil temperature stay above 60 to 70 degrees . The hard seed pelage weaken in the damp grease to allow the first root to pierce downward and the first leaves , the cotyledons to push to the dirt surface .

Growth

investigator at Purdue University note that optimal growth of sunflower occur when temperatures hover between 70 and 78 degrees Fahrenheit . The taproot continues to acquire downward as far as 6 feet to cast anchor the plant , while many fibrous antecedent radiate outward from the theme base in the top six inches of soil . The single stem grow hollow and smooth , uncover large jigaboo - mould leaves from the grow tip as it elongates . After about 30 days , the plant ’s maturate tip reveals the first hints of development of the terminal prime bud . The plant stalk becomes more woody and change from being smooth and rounded to firm and angle .

Flowering

About three weeks after the flower bud first becomes seeable at the tip of the sunflower base , it enlarges and begins to unfurl to reveal a flattened disk . Over the trend of one workweek , the yellow ray florets , the flower petal , roll back on the flower nous ’s edges and the disk florets bloom across the core of the sunflower bloom . Bees pollenate the disk florets . After about one week the helianthus shed its ray floweret . torpid bud depress down the flora stem may sprout from the base of leaves to develop into junior-grade flower heads .

Seed Development

Once the sunflower blossom finishes blooming , the primal core of disc florets swell and develop into seeds , ripening over the course of about 30 Day . Once ripe , each seed prohibitionist and gradually exuviate aside the ground below or is plucked aside and eaten by a hungry bird or small rodent . As the ejaculate mature in the head , the repose of the helianthus plant begins to go down with yellow and aborting leaf as energy focalize on the seed head .

Death

Once seeds mature and naturally disgorge , the helianthus plant check development . Plants do not die until nighttime temperatures drop below 28 degree Fahrenheit . Even if temperatures in fall and wintertime do not send away below freeze , the helianthus plant become flat since the flood tide of its biography , the flowering and production of seeds , has occurred .

References

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