When To Dig?

Use all available tools and information to help
make this decision.

By Amanda Huber

Factors Affecting
The Digging Decision:

• Variety
• Acreage
• Frost potential
• Soil conditions
• Balance between pod matu- ration and natural pod shed
• Length of growing season
• Disease (late-season vine protection to hold mature pods on the plant)
• Other crops and management requirements

Source: David Jordan,
NCSU Extension Agronomist

A famous man once said, “It is a riddle, wrapped in a mystery, inside an enigma; but perhaps there is a key.” Sir Winston Churchill said this of Russia in a radio broadcast in October 1939, but he may as well have been talking about peanut harvest in any given year.

Knowing when to dig may be the biggest dilemma producers face, but there are some keys to help in this decision.

Maturity Determines Yield And Grade

“Determining when to dig is highly important because peanut maturity determines grade and yield,” says Jay Chapin, Clemson University Extension peanut specialist in the Peanut Money-Maker Production Guide. “Over-mature peanuts can quickly lose peg strength, resulting in significant yield loss.”

  

The Digging Dilemma:

• If a grower with 300 acres with a yield potential of 4,000 pounds per acre of peanuts digs Sept. 25, when peanuts are less mature (optimum maturity is Oct. 5), the grower could lose $9,600 (15 pounds per acre per day x $0.21 per pound peanut selling price x 10 days = $32 per acre x 300 acres).

• If the same grower delays digging until Oct. 5 when peanuts are more mature, but we get a hurricane that prevents digging until late October and 25 percent of the pods shed off, the grower may lose $63,000 (25 percent pod loss x 4,000 pounds per acre yield x $0.21 per pound peanut selling price = $210 per acre x 300 acres).

• Deciding when to dig peanuts is perhaps the most stressful decision a grower makes. How often does the 25 percent yield loss occur because of poor weather versus the loss in yield and market grade because of early digging each year?

Source: David Jordan, NCSU Extension Agronomist
 

“After a season of good management, timing of harvest can be the critical aspect that can result in high yields and high grades or low grades and less than optimum yield,” says David Wright, University of Florida Extension agronomist. “Growers use different approaches in timing digging including days from planting, potential weather events, disease pressure, hull scrape and pod blast evaluations. However, different areas of the field may mature differently with fertility and moisture availability.

“Knowledge of fields, experience and keeping pods and pegs healthy with a good fungicide program are critical in case there are delays due to weather, break downs or harvest of other crops.”

Timing More Critical In Some Years

 

Days After Planting:

Days after planting should never be used as a sole basis for determining when to dig, but it is a good guide for when to check fields and can be used in combination with other methods.

Source: Peanut Money-Maker Production Guide 2009

Wright says all growers strive to harvest at the proper time, and it is very critical in years when moisture has been abundant and disease pressure is heavy.

The following information are guidelines and tools to use in making the decision of when to dig. Producers should also attend pre-harvest clinics and seek the advice of Extension and other experts to obtain as much information as possible to make an informed and knowledgeable digging decision.

PG

Hull Scrape Maturity Testing Method

1. Approximately 110 days after planting, collect three to five adjacent plants from three locations in an area of a field that can be dug in one day. For early maturing varieties, pull a sample at 95 days after planting.

2. Remove all pods from the plants from each area to obtain 180 to 220 pods. Complete picking of one plant once started. Repeat for each sample.

3. Use a pressure washer, oscillating or “turbo” type nozzle and wire basket or bucket with drainage holes to blast away the outer layer of the pod sample.

4. Examine the hull color. As peanuts mature, the mesocarp color changes from white to yellow, to orange, to brown and finally to black.

5. Based on hull color of the pods, place them on the peanut maturity profile board. Keep the pods wet.

6. Determine days to optimum maturity on the basis of slope line and harvest projection line. Find the point at which the leading edge (slope) of the sample profile crosses the projection line. Read the days until digging directly below the first column from the right that contains three pods.

7. A second sample should be taken about 10 days before the predicted date to verify maturity progression.