Growing a giant pumpkin is a labor of love. Giant pumpkins needs constant care and attention, and in the end you'll have a large, round beast of a vegetable in front of you ready to take on any competitor for size and weight. Part of the care of growing such a big pumpkin is feeding it. With the right levels of water soluble fertilizer applied with regularity, you can see as much as a foot of vine growth a day, and your pumpkin will continue to grow larger for months.
Plant your pumpkin seedlings in loose, loamy soil in a spacious, full-sun location. Mix a gallon of water with the appropriate dosage of fertilizer A (see Things You'll Need), according to the manufacturer's instructions, and use this as the seedlings' first watering.
Dose the pumpkin with another gallon of fertilizer A one week later, and apply this fertilizer to the pumpkin each week from May through June.
Keep weeds away in these early months as the pumpkin focuses on root growth, by using a cultivator to strip young weeds out of the top layers of soil. As you remove the weeds, be careful not to disturb the roots of the pumpkin or the stems.
Switch to regular, weekly applications of a gallon of fertilizer B for the month of July.
Add a wide ring of well-rotted manure around the main stem of your pumpkin, up to four inches deep, in early July, and leave the ring in place for the remainder of the season.
Use fertilizer C starting in August, and continue applying a gallon of it to the pumpkin until you notice the pumpkin is ripening and the vine starting to dry and turn brown.