Giant Pumpkin Growth and Life Cycle

Giant Pumpkin Immature

Anyone who has grown these behemoths will agree, the giant pumpkin growth and life cycle is fast, enormously strong, and furious. At the end of the season, it usually crawls to the finish line, as cooler weather and shorter daylight hours brings increasingly slower growth.

Here’s a chronology of the life cycle of this prolific plant. It will help you to gauge when to plant your seed and all the big steps in between. Adjust the start date to best fit your area.

Chronology of Giant Pumpkin Growth

Day #DateEvent
1April 24thPlant seeds indoors. Competitive growers start between April 24th and May 5th. Don’t worry if you get a late start. You can start a giant pumpkin as late as the end of May.
5  April 29thPlant back-up seeds. Avid giant pumpkin growers know, many things can go wrong with germination and early seedling growth. Always have a few extra, just in case……
9 – 10May 5thHappy Birthday, seeds explode from soil
20May 12thFirst true leaves appear
22 – 25May 15thTransplant  seedlings into the garden
25 – 36May 15th – May 30Provide evening cover to protect young seedlings from cold and frost.
51June 15thThe “Battle of the Bugs” begins
70July 1-14thPollination time
73July 20thBreath sigh of relief, pollination is successful.
75July 9thSwitch to higher phosphate fertilizer or supplement
80July 14thBuild shade cover for fruit
81July 15thNo amount of water is enough, ditto for fertilizer. Water deeply. Keep soil moist, not wet.
82July 16thThe “dog days” of summer bring humidity- apply fungicides
96July 30thThe monster is 100 to 150 pounds, give or take 50 pounds
100August 4thThe skin begins to take on a harder texture, ribs begin to form
111August 15thBright yellow skin is slowly darkening. Will it turn orange!?!
126August 30thShorter hours of sun and genetics slows growth
141September 15thCooler weather, shorter days, translates to slow growth
156September 30thPumpkin is mature and orange.
159October 6thThe fork lift digs up the lawn, as you harvest your giant pumpkin.
160October 7thYour monster is new world record at the Giant Pumpkin Weigh offs!!
161October 15thQuarterly Water Bill arrives.

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