Video: What Stage Are My Soybeans In? R4 to R6

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As our soybeans move from flowering into pod development we also start to focus our management on protecting and providing for those pods. This video shows how to tell the differences between R4 through R6 growth stages in soybean.

When staging soybeans look only at the upper four-most nodes with a fully developed leaf. This is for consistency purposes since soybeans often continue to flower as pods are developing, and there can be pods of multiple sizes on the same plant. When 50% of the plants in a field have reached a growth stage that’s when we say it’s moving on to the next growth stage.

soybean pod 3/4 inch long

Growth Stage R4 in Soybean – Full Pod

R4 – Full Pod: Pods will be ¾”long.

seed 1/8th of an inch wide

Growth Stage R5 in Soybean – Beginning Seed

R5 – Beginning Seed: Seeds are ⅛” wide. (About 1/2 the width of an average pencil eraser.)

Soybean plant in pod fill

Growth Stage R6 in Soybean – Full Seed

R6 – Full Seed: Green seeds that fully fill out the cavity of the pod.

Knowing the growth stages of our soybeans is important after flowering, especially since the impact of pest presence and pressure on the crop changes during this time. Soybeans are very susceptible to seed damage in R4 and R5 but as we move through R6 the soybeans become less susceptible to economic injury. This is why treatment thresholds for many important pests will increase around R6.

Additional Information:

NC State University – Soybean Staging Guide

CoolBean Visual Guide to Soybean Stages

University of Arkansas SoyStage Website

Filmed at: N.C. Department of Agriculture and Consumer Services Piedmont Research Station, Salisbury, NC