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.
| Day # | Date | Event |
| 1 | April 24th | Plant 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 29th | Plant 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 – 10 | May 5th | Happy Birthday, seeds explode from soil |
| 20 | May 12th | First true leaves appear |
| 22 – 25 | May 15th | Transplant seedlings into the garden |
| 25 – 36 | May 15th – May 30 | Provide evening cover to protect young seedlings from cold and frost. |
| 51 | June 15th | The “Battle of the Bugs” begins |
| 70 | July 1-14th | Pollination time |
| 73 | July 20th | Breath sigh of relief, pollination is successful. |
| 75 | July 9th | Switch to higher phosphate fertilizer or supplement |
| 80 | July 14th | Build shade cover for fruit |
| 81 | July 15th | No amount of water is enough, ditto for fertilizer. Water deeply. Keep soil moist, not wet. |
| 82 | July 16th | The “dog days” of summer bring humidity- apply fungicides |
| 96 | July 30th | The monster is 100 to 150 pounds, give or take 50 pounds |
| 100 | August 4th | The skin begins to take on a harder texture, ribs begin to form |
| 111 | August 15th | Bright yellow skin is slowly darkening. Will it turn orange!?! |
| 126 | August 30th | Shorter hours of sun and genetics slows growth |
| 141 | September 15th | Cooler weather, shorter days, translates to slow growth |
| 156 | September 30th | Pumpkin is mature and orange. |
| 159 | October 6th | The fork lift digs up the lawn, as you harvest your giant pumpkin. |
| 160 | October 7th | Your monster is new world record at the Giant Pumpkin Weigh offs!! |
| 161 | October 15th | Quarterly Water Bill arrives. |
