AUBURN, Ala.— Pod blasting is an improved method farmers use to determine optimum peanut maturity for harvest.
For many years, peanut producers used the pod scraping method, where pocketknives—or other sharp objects—were used to scrape away the outer layers of the shell. Alabama Cooperative Extension System Peanut Research Associate, Kris Balkcom, said the widely adopted use of lightweight pressure washers has allowed producers to determine peanut maturity with relative ease.
Pod blasting requires different equipment than pod scraping, but is a more efficient and reasonably quick process.
Balkcom suggests a lightweight pressure washer, with a PSI of 1300-1600.
“Many of the immature pods are full of water, so it is easy to tear them apart,” he said. “Using a lightweight pressure washer will prevent the destruction of the pods.”
Keeping pods in tact allows producers to have a more accurate maturity reading, and to plan the digging and harvest times accordingly. Mature pods are harder and do not damage as easily.
“Producers need to be able to scrape off the outer layer of the hull to see the color,” Balkcom said. “The color of the inner hull helps to determine the level of maturity.”
Balkcom and other industry and Extension professionals use a heavy metal basket to aide in the pod blasting process.
Baskets are made of expansion metal with grated sides and a subfloor midway up the cylinder. The screen-like sides and subfloor allow the water to run out of the peanuts, taking the outer hulls with it. After blasting, the varied colored peanut hulls are left in the basket. Producers then use a peanut profile board to determine potential harvest time.
Pod blasting removes the outer hull of the peanut, revealing the color of the inner hull, which is what farmers use to measure maturity. Most producers use the peanut profile board to measure the average maturity level of their fields.
Peanuts on the lowest level of maturity will have white hulls. As the pods mature, they become yellow, then transition to orange, brown and black. Black pods are the most mature.
Balkcom lines the peanuts up on the profile board and uses the slope and projection lines to determine the percentage of peanuts at a certain maturity level in the field, and in turn is able to suggest a harvest date.
Producers also pay close attention to the skin color and oil spots on the peanut itself. Peanuts with light skin and dark brown oil spots are approximately seven days away from peak maturity. Peanuts with copper colored skin and brown oil spots are generally at optimum maturity levels.
Preparing to Pod Blast
Balkcom said the first step is to gather a representative sample from the field.
“Gathering a representative sample is done much like soil sampling,” he said. “You may go to scattered locations throughout the field and pull up a single plant. The goal is to have about 200 pods to sample from each location.”
Producers may use this opportunity to evaluate the strength of the peanut plant and stems. If the plant has weak stems and gathering samples leaves peanuts in the ground, Balkcom said harvest may already be behind schedule.
Once you’ve gathered a representative sample, pick off every pod mature enough to go through the combine at harvest. Place the pods in a bucket, or into the pod-blasting basket.
Pod Blasting Peanuts
Balkcom said pod blasting technique is important. After pouring the pods into the basket, begin washing.
The turbo nozzle on the pressure washer seems to work the best for pod blasting.
“The distance between the wand and the pods is important,” Balkcom said. “Keeping a good distance will prevent the pressure washer from destroying the peanuts.”
After washing, the outer hull will be washed off and the peanuts will be ready to place on the profile board.
“Peanuts are indeterminate, so the plants flower from 40 days of age to harvest,” he said. “There will be a mixture of all ages of peanuts in the basket. Pod blasting will help to determine the most optimum time for harvest, the best average grade and the most weight to market.”