Hula hoops = an important tool for every pulse and soybean farmer (especially in narrow rows or solid-seeded fields)

Why do they call it a hula hoop?
Because it has a nice ring to it!

By tossing a hula hoop randomly in the field and counting the plants inside, you can calculate the average plant density.

Can you picture in your mind how big one acre is?

One acre is the same size as 10,000 hula hoops (hoops with an inner diameter of 28.25″) touching each other.

By using a hula hoop with an inside diameter of 28.25″, you can then do quick math.

Plants inside the hoop x 10,000 =  the number of live plants per acre

When your soybeans or other pulses are at least at the first trifoliate stage or past the cotyledon stage, take counts from 6 to 10 spots in the field and then average those counts.

Consult the chart below to determine if your live plant stand falls with in the optimal range.

What if your hula hoop is bigger or smaller than 28.25″diameter?

You use it anyway!

But when you are in the field, you’ll need to open the MPSG Bean App on your device.

Tap on Plant Stand Assessor

Choose the fixed area method and enter the inner diameter of your hula hoop.

Even though it says Soybean population, if you’re counting in a pea, faba bean, or dry bean field it’s still okay to use this app to get the plant population number.

Randomly toss and chase your hoop. Count the number of plants in the hoop and enter the number into the app at 6 to 10 different sites through out the field. Don’t intentionally avoid plant gaps; include these in areas assessed.

Hit Calculate.

The app will tell you your average plant population and for soybeans if it’s a high, or low, or a good plant population.

***If you are counting in a pea, faba bean, or dry bean field you need to consult the chart already shown above in this article to determine if your plant stand falls with in the optimal range.***

What if I don’t want to use the app?

If you love doing math, then you can use this conversion table below for the factor you need to multiply the number of plants in your unique hula hoop to figure out plants per acre.

Diameter of Hoop	Multiplication Factor
18″	24,662
21″	18,119
24″	13,872
27″	10,961
30″	8,878
33″	6,165

Courtesy: cropprotectionnetwork.org

What if I don’t have a hula hoop? or I only have a tape measure/ measuring stick or my crop is seeded on wide rows?

Then it’s time to count plants in a defined row length.

Assessing Soybeans Grown in Rows (some people have a chain that is 21″ long that they use to determine where to count.)

Row spacing, the number of rows to count, and row length to measure for determining soybean plant populations in 1/10,000 of an acre.

Row Spacing	Number of Rows to Count	Row Length = 1/10,000 Acre
7.5″	4	21″
15″	2	21″
30″	1	21″

Or what if I only want to count 1 row at each of my sample spots in the field?

Row Lengths Equal to 1/1000 of an Acre at Different Row Widths

Row Width	Length of Row
36″	14’6″
30″	17’5″
22″	23’9″
15″	34’10”

It’s very important for farmers to have a really good idea of how many plants made it all the way to the early seedling stage and compare that to how many seeds they targeted to put into the ground. Counting plants now can highlight seed lot or equipment issues or seeding rate mis-calibrations.

Knowing the range of your personal per cent seed survivability is important to use when making future seeding rate calculations. Especially after experiencing multiple environmental challenges so far in 2026, the per cent seed survivability will vary from field to field. Make notes on these differences and list some of the potential contributing factors.

Plant stand counts are critical if you’re at the point where you must decide on a reseeding decision. If you’re keeping what you have, plant stand counts can help with the decisions of investing more money into the crop and spraying herbicides. Low plant stands will face more yield robbing pressure from weeds than thicker stands and will benefit greatly from timely and effective herbicide applications.