Rebel you probably seen regular sunflowers right, I had a cultivar I grew without using the magic worm-tea and fish-guts my teacher wanted me to use to maximize their growth rate. My Godzilla Sunflowers grew to 16ft tall, there are guys who got theirs to 23ft tall!
http://www.guinnessworldrecords.com/world-records/tallest-sunflower
Have you seen how professional melon growers start germination inside their house, than during the winter they keep these plants slowly growing with tons of hay, covered in plastic (minor green house affects) continual fertilizers plus add-ins while their march towards a goal of 300lbs might happen?
http://www.hopechamberofcommerce.com/melon_heritage.htm
I studied Bio-dynamics(Some believe it's pseudo science or witch craft) along with regular agricultural practices, one famous bio-dynamic scientist helped restore land devoid of nutrients during the Dust Bowel. Rudulf Steiner is probably considered insane by chemical ag majors with his ancient rituals trying to impregnate Earth's soil back to a state of richness cotton and tobacco destroyed, their clueless how our environment is. Have you seen grapefruits weighing 3lbs, Blueberries as big a Strawberries ect?
Dealing with these issues after seeing how Science has helped food grow incredibly huge has no bearing on someone who has farmed and believes the Intelligent Consciousness if so desire could make the Earth sprout massive cultivars! Dave Wilson uses Zeiglar Genetics in the San Juaquin Valley, Zaigler has produced the strangest and hardest stone-fruits, apples, blueberries (Plue-erries), Aprium, Pea-cot-um through millions of trial and error plantings plus his resistant root-stocks are world famous. If the Universal Consciousness decided to make things big by turning up the Earths productive powers, it's not far from imagination. People ask us to believe Life sprouted from Nothingness, my brain has a much harder time wrapping it's head around that than over-sized fruits I have seen at Fairs in the Midwest and Georgia hybrid peaches! Just my opinion as a grower (eight generations our family grow and raised cattle at various times and back to Holland where they probably grew tulips bulbs of tremendous size)