The 747 pumpkin (aka Jumbo) is at 72 days old now. 90-100 days about how long most pumpkins will grow. A good one might go 110 days, but typically not more. I did a measurement on my pumpkin today and growth has dropped 6 pounds a day as compared to the week prior. I'm hoping that is somewhat because I believe the pumpkins didn't get watered for two days while I was gone. The timer was all messed up when I got back and the soil was relatively dry, so I think that might have been the case. We'll check again in a week. But at 72 days you can expect growth to slow down a fair amount.
Late season growth can make or break a season. Some pumpkins are hares. Some are tortoises. But in the end, all that matters is the final weight on the scale. Like I mentioned before, I've been trying to fertilize more this season. I think I've under fertilized in the past. Next season I'll probably increase my fertilizing even more. Matt McKonkie fertilizes every day. This is small spoon feeding, but enough to keep the pumpkin growing and never be deficent.
In the past, my September growth has been poor. I thought it might be weather, which is a factor, but now I think it has more to with the plant bonking because it has used up much of the nutrients int he soil by late season.
Today I gave the plants NPK Potassium, Omina, Cal Mag, humic acid, cane molasses and B-vitamins. That was mostly put on the soil.
Matt made told me he doesn't put anything on the leaves (i.e. no foliar feeding) because he thinks the leaves aren't really made to bring in nutrients and it damages the leaves. I think I'll still foliar feed, but do it less frequently. If something potentially is locked up in the soil then foliar feeding is the best way to fix it, but I'm going to reduce how much I foliar feed next year.