Soybean Planting Calendar by Maturity Group

A soybean maturity group is a rating that tells you how a variety responds to day length, and it sets how well the variety fits your latitude and your planting date.

Key points

Maturity group matches a variety to your latitude and planting date.
Usual NASS planting windows are a guide, not a date to pick.
Delayed planting often calls for an earlier group, so ask your local specialist.
Use multi-year, multi-location university variety trials to choose a variety.

What does soybean maturity group mean?

Maturity groups are numbered classes that describe how a soybean variety responds to day length. Lower numbers suit northern areas with long summer days and short seasons. Higher numbers suit the South. Within a state, extension specialists often recommend a range of groups, and the range shifts with latitude and with planting date.

This is why a variety that does very well in southern Missouri can disappoint in northern Iowa. Soybeans flower and mature in response to the shortening days of late summer, so the wrong group may mature too early, leaving yield on the table, or too late, getting caught by frost. Texas A&M, Iowa State, NC State and K-State all publish guidance that links maturity group to location and planting date, and your own state guide is the one that counts.

When is the usual soybean planting window?

USDA NASS publishes usual planting dates by state. In the October 2010 edition, the most active soybean planting window runs from about the second week of May to early June in Iowa and Minnesota, about May 5 to June 22 in Arkansas, and about May 15 to June 20 in Kansas. These windows are wide in the South partly because many growers there double-crop soybeans after wheat.

Use these windows to see the general shape of the season, not to pick a date. Your local conditions and the frost dates on your own farm will decide whether the beans go in early or wait.

Planting windows widen in the South because of double-cropping
Northern growers have a tighter window between frost risk and fall frost
Always compare the window to your own frost dates

How does planting date change the maturity group you choose?

As planting is delayed, many extension recommendations move toward earlier maturity groups, because the plant has less time before the days shorten. Early plantings in a warm, well-drained field can often use a fuller-season variety and take advantage of a longer growing period. Planting later than usual may call for a shorter-season variety or a different plan altogether.

For example, if you farm in an area where a mid-maturity group is the local standard and you expect to plant three weeks late because of a wet spring, ask your seed dealer and extension agronomist whether to stay with the standard group or step down. Do not guess. The answer depends on local variety trials, which universities publish each year.

What should you check in the field before planting soybeans?

Soybeans are a warm-season crop. Cold, saturated soil slows emergence and can increase seedling disease pressure. Look at soil temperature trends, at the forecast and at how the field is draining. Check last year's residue and the weed situation as well, because early weed control is easier than late weed control.

Soybeans emerge with the growing point above ground, so a hard frost after emergence can do real damage. That makes your local last frost date more important than it is with corn. Ask your extension office what the frost risk looks like in your county before you commit to early planting.

How do you pick a variety within a maturity group?

Once you know the group range, look at university variety trials in your region. Compare yield across several locations and several years, not one test plot in one season. Look at disease and lodging notes and at traits that match the problems you actually have, such as a specific soil disease, which your extension plant pathologist can help you identify.

If you use pesticide products on soybeans, follow the label exactly. The label is the law, and pre-harvest intervals apply. Applicator licensing rules vary by state, so confirm what is required where you farm, and protect pollinators by following label directions on timing.

What records help you refine soybean timing over time?

Keep a simple field log: planting date, variety and maturity group, emergence date, any frost or crusting events, flowering date and harvest date. After three or four seasons you will see patterns that no statewide table can give you, such as which fields warm up first and which hold water in spring.

Share your notes with your extension agent or crop adviser at the end of the season. They often compare many farms and can tell you whether your results match what trials show. If a field keeps underperforming at one planting date, that is useful information, and you may be able to adjust the date or the group next year without any new equipment.

Log planting, emergence, flowering and harvest dates
Note frost, crusting and standing water events
Review the log with your adviser each winter

How does double-crop soybean timing differ?

In the South and parts of the mid-Atlantic and lower Midwest, soybeans are often planted right after winter wheat or barley comes off in early summer. The NASS windows for states like Arkansas and Kansas run late partly for this reason. Double-crop beans have less time to grow, so extension usually recommends a different maturity group range and attention to soil moisture at planting.

If you plan a double crop, think about when the first crop will be harvested, how quickly you can get the second planted and whether your area gets reliable summer rain. Ask extension whether double-cropping is a good bet in your county in dry years.

Timing at a glance

Timing ranges for this topic
Item	Window	Caveat
Soybeans, Iowa	Most active planting from about May 8 to June 2	Usual dates describe typical field activity in that state, not a safe date for your farm. Check your own last frost date, soil temperature and your state extension guide.
Soybeans, Arkansas	Most active planting from about May 5 to June 22	Usual dates describe typical field activity in that state, not a safe date for your farm. Check your own last frost date, soil temperature and your state extension guide.
Soybeans, Kansas	Most active planting from about May 15 to June 20	Usual dates describe typical field activity in that state, not a safe date for your farm. Check your own last frost date, soil temperature and your state extension guide.
Soybeans, Minnesota	Most active planting from about May 8 to June 2	Usual dates describe typical field activity in that state, not a safe date for your farm. Check your own last frost date, soil temperature and your state extension guide.

When to get local help: Ask your county extension office or a certified crop adviser which maturity groups are recommended for your latitude and planting date.

Sources and further reading

Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.

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