I'm writing this hoping it will stimulate Giant Pumpkin Growers to experiment and write articles reporting their results.
The company I buy most of my fertilizer and pesticides from puts on seminars that I attend to obtain credits needed every 6 years to re-certify my Pesticide Permit. They are aimed at corn, soybean and small grain growers. As I listen I’m thinking: "Is this information useful for growing GIANT pumpkins?"
Most data presented are results of studies at Ag Colleges and studies sponsored by Seed, Fertilizer and Chemical companies
At a recent Seminar some information was presented that I want to share with you. Some of it may apply to growing Giant Pumpkins.
In 1960 US farmers averaged 60 bushels of corn per acre. Today most obtain 150 to 200 and a few exceed 300 bushels per acre on non-irrigated land. I think 300 bushels per acre of corn is about the same as growing a 1000+ pound pumpkin. Only a few do it!
It was reported corn roots reach a depth of 4 feet and soybeans at least 3 feet .Using a sub-soiler every 3 to 4 years is required in heavy soils.
Some 300-bushel per acre corn growers FALL plow to a depth of 14 to 15 inches. One of these reported: “With the fall plow-down I apply 50 pounds of Nitrogen, 220 pounds of Phosphorus and 180 pounds Potash per acre. In April 380 to 400 pounds per acre of Nitrogen is applied”. He also applies 150 pounds per acre of 4-10-10 liquid started with his corn planter. The soil is tested when the corn is 4 feet tall and sometimes 50 pounds per acre of Nitrogen is dribbled between rows with a high clearance rig. He said he farms average ground and has had corn on the same ground for 32 years.
Questions: Have you used a sub-soiler, plowed to a depth of 14 to 15 inches and applied some Nitrogen and most of your Phosphorus and Potash in the fall? Have you used 450 to 500 pounds per acre of Nitrogen? That is about 2.5 times what I use for my Giant Pumpkins. Could they benefit from more?
A study at 3 locations resulted in a 20% corn yield increase when two-thirds of the Nitrogen was applied prior to planting and one-third side dressed later compared to 100% prior to planting. Raising Sulfur from 10 PPM (parts per million) to 25 PPM increased corn yield 17%. WOW!! In 2 studies adding 1.5 pounds per acre of Boron increased corn yields by 15% and 22%. WOW again!! A study adding 1 pound per acre of 120% chelated Zinc increased corn yield 9%. One study found corn yield was 31% lower in rows under tractor tires that pulled the corn planter due to compaction. That’s a huge loss. Do you minimize compaction?
Soil pH is of interest to all growers. The following study quantifies the relative percent yield for 3 pH levels. This is the first study I’ve seen that quantifies what you lose by not having near-optimum pH.
||Relative % Yield
Soil temperature is probably as important for Giant Pumpkins as for corn. It was reported corn growth DOUBLES for each 11 degree F increase in soil temperature. I prune runners to have a minimum of 2 feet between them. My plants may benefit from wider runner spacing to obtain higher soil temperature as more sunlight reaches the soil.