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Understanding each stage of soybean growth and development can help you improve your crop production. Let’s take a close look at the details of soybean growth along with tips for successfully managing your crops through every stage of development during the upcoming growing season.
Soybean growth stages are divided into two categories of plant development: vegetative (V) and reproductive (R) stages.
Vegetative soybean growth stages are identified and numbered according to the number of fully developed trifoliate leaves present.
📸:@Likica83 via Canva/Featuring an image of fully developed trifoliate years .
Reproductive stages occur when soybeans begin flowering and continue through subsequent stages, including pod development, seed development and, ultimately, plant maturation.
Keep in mind that your crop doesn’t enter a new soybean growth stage until at least 50% of the plants in a field are evidently in or beyond that respective stage. Within any given crop, since individual plants can mature at slightly different rates, there's often a fair amount of overlap between the various stages.
📸:@ilyakalinin via iStock for illustration/Featuring a graphic of soybean growth stages.
The vegetative growth stages for soybean include:
On average, the VE stage occurs 10 days after planting. This timeline may vary depending on soil temperature, moisture level, soybean seed variety and planting depth. The VE stage (often called the cotyledon stage) begins when seed has absorbed water equivalent to approximately 50% of its initial weight (for example if the seed weighed 1g it would have to absorb 0.5 g in water) and the primary root (called a radical root) emerges. During emergence, the embryonic first leaves of the seedling (called cotyledons) are pushed to the soil surface by an elongating stem (called the hypocotyl).¹
VC is the second stage of soybean growth, in which leaves on the first node (the place where a stem and leaf meet) unfurl completely. These first leaves that develop on opposite sides of the stem just above the cotyledons are single leaves called unifoliates. Many people will call this the unifoliate leaf stage. Food reserves stored in the cotyledons continue to sustain the young plant during this time.
Soybeans hit the V1 stage when the first trifoliate leaves (leaves divided into three leaflets) unroll. At V1, the plant has used up the food reserves in the cotyledons and has enough foliage to be self-sufficient as each new leaf creates greater opportunity for photosynthesis. Trifoliate leaves develop alternately as they ascend on the stem.
In V2, the second trifoliate leaf unrolls, and plants are typically 6"–8" high. At V2, active nitrogen fixation of the root nodules (the process of converting atmospheric nitrogen into a form that plants can readily use) begins. This process continues until the late reproductive stages.
A new node develops with each subsequent stage of V growth. At V3, new nodes and trifoliate leaves continue to form and unroll. The “n” indicates the number of nodes that display fully unfurled trifoliate leaves. The total number of trifoliates that may develop depends on the variety and environmental conditions.
Be on the lookout for specific management practices and input applications throughout the first growth stages.
During the VE stage, keep an eye out for conditions that may lead to soil crusting. Check your forecast and avoid planting before a heavy rainfall is predicted. A heavy rainfall event, especially when followed by limited rainfall and warm weather, can increase the likelihood of crusting. Additionally, soil that is structurally degraded is more likely to crust. When soybeans are forced to emerge through crusted soil, it can ultimately lead to poor stands.
Consider applying a starter fertilizer with your planter in a band within 2" of seed to help promote early plant growth and seed yield. Your starter fertilizer should include phosphorus and potassium, essential nutrients for early root growth, root nodulation and biological nitrogen fixation.² It is not recommended to apply fertilizer in furrow to soybeans as seed is very sensitive to salt injury.
If your stand is poor, consider replanting during this stage. Effective weed control measures are critical during the V stages to allow the stand to establish successfully, and understanding herbicide timing and application cutoff dates for soybeans is critical.
Here are some examples of products you may want to consider to protect your yield potential:
This product features flexibility across crops and timings and can be applied from preplant through V5 in soybean for control of grasses and broadleaf weeds such as waterhemp, pigweed and nightshade. Outlook® herbicide is activated with as little as ¼” of rainfall, making it a flexible option for various weather conditions.
Zidua® SC herbicide offers a long application window and can be applied from fall through early preplant and early postemergence all the way through V6 soybean. Zidua is especially strong on herbicide resistant weeds like waterhemp and Palmer amaranth with a long residual to help with late-emergings weeds. See product's label for additional application timing info.
For management of key weeds from soybean VE to R1 stages, Liberty® herbicide is labeled to control weeds that have become resistant to other herbicides such as Palmer amaranth and waterhemp. Liberty should be applied when weeds are less than 3" tall. Be mindful that post applications can only be applied to LibertyLink® soybean.
At V1, scout for early-season weeds to ensure weed pressure doesn’t overtake the young crop, hindering photosynthesis and competing for nutrient availability. Additionally, insect and disease pressures should be managed with insecticides, fungicides and integrated pest management practices starting in the V stages.
The following insecticides are labeled for use during the V growth stages through the R stages.
Fastac® CS has a broad application window and may be applied before, during, or after planting to provide control of a range of common crop-damaging pests, including aphids, beetles, caterpillars and stink bugs.
From VE through R8, soybean aphid, bean leaf beetle, Japanese beetle and other chewing pests can be controlled by Renestra® insecticide’s dual mode of action.
Sefina® insecticide protects soybean yield potential by rapidly stopping aphid feeding without any pollinator restrictions, which allows for more flexibility in application timing. Sefina is labeled for use from VE through R8.
Continued management of common soybean weed, insect, and disease threats is key throughout the rest of the V stages.
The reproductive stages in soybean typically span from late June to October in the Midwest. The critical reproductive growth states of soybeans include:
Throughout the reproductive growth stages, it is important to monitor disease and pest pressures as well as water-related stress, especially during R1 through R5. Applying foliar insecticide or fungicide during the reproductive stages may be necessary.
📸: Featuring a photo of a flowering soybean plant likely at R1 or R2.
The visual marker for R1 soybeans (beginning flowering) is the appearance of at least one flower that has opened at any node on the main stem. Flowers usually appear somewhere between the third and sixth node. As flowering continues, blooms will appear up and down the plant's stem.
The R2 soybean stage (full bloom) typically occurs approximately three days after R1. R2 occurs when a flower appears on one of the two uppermost nodes on the main stem and the plant has a fully developed leaf on one of these uppermost nodes. Warmer weather conditions can lead to an extended flowering period, with R2 lasting up to seven days depending on environmental conditions. Extended flowering may have a positive impact on yield.³
Soybean plants begin setting pods during R3. Pods that are 3/16" long on one of the four uppermost nodes on the main stem, along with a fully developed leaf, indicate your crop is in the R3 soybean growth stage.
R4 is considered the most critical stage for soybean development and subsequent seed yield. R4 soybeans should have pods ¾" long on one of the four uppermost nodes on the main stem with a fully developed leaf. Yield reduction during the late R4 stage is mainly from fewer pods developing. This period is to consider irrigation if needed and available.
R5 is when soybean root growth slows and rapid seed filling begins. Seed is typically ⅛"' long in one of the four uppermost nodes on the main stem.
By the R6 soybean stage, beans of many sizes appear on the plant, with pods containing a green seed that fills the cavity in one of the four uppermost nodes on the main stem.
📸:@Eny Purwanti and @Ethan R. Via Canva/Featuring a comparison of soybean pods at R7 (left) and R8 (right)
Look for one pod on the main stem that has reached the mature pod color (tan or brown). At this stage, the soybean plant is visually yellow since all green color is lost from seeds and pods. This will indicate your crop is in R7.
When 95% of the pods have reached their mature color, your crop has reached the final stage, R8, and is considered at full maturity. R8 typically occurs five to 10 days before harvest.
Ensure you are implementing the proper management practices and input applications throughout the final growth stages.
Continually monitoring your R stage soybeans is critical. For example, R3 soybeans (and later R5 soybeans) are especially susceptible to water stress, so if irrigation is typically required in your fields, make sure you are sufficiently irrigating your crop during these stages.
The optimum timing to protect your crop from disease is during the early reproductive stages before disease onset. Keep an eye out for soybean diseases and insects during all R stages.
Applying fungicide treatments like Endura® fungicide R1 to R2 can help proactively protect your crops from diseases such as soybean white mold.
Revytek® fungicide can be applied between the R2 and R4 growth stages to fight diseases like soybean rust and frogeye leaf spot.
Another fungicide for the R2 through R4 growth stages, Priaxor® fungicide can protect soybeans from a variety of diseases, and other yield-limiting stressors.
R5 soybeans are especially susceptible to water stress as well. Additionally, storm damage from hail in late-season soybean crops can cause significant damage. For example, if weather conditions cause 50% defoliation, this can decrease your yield by up to 17%. Looking into crop hail insurance may be worthwhile.
Starting in R7, be on the lookout for issues like green stem disorder, sprouting seeds and pod shatter. At R8, keep a close eye on the weather forecasts. Soybeans require five to 10 days of dry weather in R8 to dry the seed to less than 15% moisture for harvest.
Understanding soybean growth stages can help you manage your fields as effectively as possible. Being aware of the most relevant management practices and crop threats at each vegetative and reproductive growth stage can help you establish priorities based on these timeframes, allowing you to prepare for any weather and disease-related threats that may arise.
For additional information on soybean growth stages, advice on seed selection or tips on choosing the right herbicide, insecticide or fungicide application, contact your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.
Learn more about how to maximize this year’s soybean crop:
Experts are available to help you make your decisions. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative.
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Always read and follow label directions. Grow Smart, Outlook, Zidua, Liberty, Fastac, Renestra, Sefina, Endura, Revytek, and Priaxor are registered trademarks of BASF. Copyright 2024 BASF Corporation. All rights reserved.
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January 7, 2025
