Like I've talked about before, growing big pumpkins in Denver is not easy. There is an area called the orange belt, that runs from Boston through the mid-west to Oregon where giant pumpkins tend to grow best. That line doesn't go through Denver. Cool nights, sometimes hot days, high UV rays and low humidity slows up growth in our climate. To make up for that you have to "make them think they are in Iowa." That is a favorite quote from one of the most experienced growers in Colorado. To do this I've got hail netting over my plants not only to protect them from hail (and they have had a workout this last week) but also to protect the plants from the sun. Anything over about 90 degrees and photosynthesis starts slowing down in a pumpkin plant and the plant has difficulties moving enough water to the big leaves fast enough to keep up with evaporation. My hail netting shades the plant with about a 14% shade block which reduces the UV rays hitting the leaves, cools the plant slightly and protects the plants from the elements. I also mist the plants throughout the heat of the day to get the humidity up and cool the leaves down.
The last few days the pumpkin plants have thought they were in Iowa. An early monsoonal flow into Colorado has brought higher humidity, big but short rains and warmer temperatures. My plants have reacted positively to it all. I don't remember the vines ever growing faster when there were pumpkins on the vine. I'm trying to hold off on terminating the vines right now because there is a lot of energy stored up in those water laden vines and if it doesn't have anywhere to go you can run into problems. My challenge is that I'm starting to run out of space on the sides of the patch and the vines need to be terminated very soon.
The picture of the plant is my 868 Johnson plant. I love the look of the leaf canopy on this plant. The leaves are shorter so they don't get caught in the wind quite as much but it is hard to get even watering under the leaves however. The chairs in the picture are covering recently pollinated pumpkins to keep them cool and dry.
Gave the plants about 1/2 cup of gypsum each today.