Purdue University - Extension - Forestry and Natural Resources
Have you heard the old adage “proper planning prevents poor performance?” This adage applies perfectly to establishing food plots for wildlife; you just have to adjust the words, “Proper planting prevents poor food plot performance”.
When we talk about planting we include planting method, timing, depth, and planter calibration (see video), but we also include seeding rate. While there are many steps prior to planting to ensure a successful food plot, including taking a soil test, adjusting the soil fertility, and proper site preparation, determining the proper seeding rate based on pure live seed rather than bulk weight may be one aspect that people skip or ignore.
All agronomic seeds have a recommended seeding rate. This is the rate that maximizes forage or grain production and minimizes seed costs. Planting food plot seed too heavily is often a waste of money, because it increases your seed cost, but does not necessarily increase you forage or grain production. Planting food plots too lightly is an inefficient use of field space, opening areas up for weeds to overtake your planting, and could result in failure because of overbrowsing.
Seeding rate also varies by planting method and it’s important to make sure to follow the recommended seeding rate for the planting method you will be using. This rate is greater when broadcasting rather than when drilling or planting seed (broadcast rate: 75-100 lbs/ac vs. drilling rate: 50 lbs/ac for iron-clay cowpeas).
It is important to recognize the difference in how seed is sold (bulk weight) and how seeding rates are recommended (pure live seed [PLS]). When you buy seed from a supplier you are buying it in the form of bulk weight. Bulk weight is the total weight inside the bag, including the food plot seed, as well as the weight of the seed coating and other material (other crop seed and weed seed).
While seed is sold by bulk weight, seeding recommendations are commonly given as PLS rates. This distinction is important. For example, all the recommendations in A Guide to Wildlife Food Plots and Early Successional Plants by Dr. Craig Harper, University of Tennessee Extension are given in PLS rates. Pure live seed is the living seed of the intended crop that will germinate from a seed bag and accounts for the weight of the bag made up of impurities, weed seed, and other crop seed.
Percent PLS in a seed bag varies, depending on the amount of pure seed in the bag as well as the germination rate of that seed. It is important to know the difference between PLS and bulk weight so that you can calculate the amount of bulk weight you need to achieve the recommended PLS seeding rate.
Keep the distinction between bulk weight and PLS weight in mind when buying seed to ensure you purchase enough seed to cover the entire area of your food plot. In this article we will explain how to calculate PLS based on information given to you when you purchase seed.
Dissecting a seed tag – know what you’re getting before you purchase
Before we get too far into calculating PLS, it is important to understand what information you get when purchasing seed. Regardless of whether you buy a seed mix or a single species from a co-op, feed store, or sporting goods store, all agricultural seed sold in Indiana must come with a label – commonly called a seed tag. By law, that seed tag must contain these 12 items: 1) commonly accepted name (species) and variety, 2) lot number, 3) origin of seed, 4) company who labeled the seed, 5) percentage of pure seed (>5% of weight), 6) percentage of other crop seeds, 7) percentage of inert matter, 8) percentage of weed seed, 9) species and amount of any noxious weeds (if present), 10) germination rate, 11) hard seed, and 12) calendar month and year the bag was tested.
Important items to look for when purchasing seed are explained below.

As we can see from this red clover seed tag above, only 65% (32.5 lbs) of the 50 lb bag is actually red clover (Pure Seed). Most of the other weight is the inoculant (Coating Material; 34% or 17 lbs). Of the 32.5 lbs of red clover seed, 80% will germinate after planting (Germination). So, if you planted 15 lbs (bulk weight) from this bag (recommended PLS rate) you would actually be planting 9.75 lbs of pure seed, of which only 7.8 lbs would germinate. Meaning you would be planting a little over half the recommended rate. See why PLS is so important now?
Clover seed: bag half empty or half full?
It may seem odd to buy a 10 lb clover seed bag only to expect 5 lbs to actually grow, but in the case of legumes – like clovers – the 5 lbs in the bag that isn’t seed may actually save you money in the long run. Having as little as 50% PLS in a bag of clover is not uncommon, as much of the weight is made up of the seed coating, which is typically an inoculant. The inoculant on clover, soybeans, alfalfa, or other legumes is living bacteria that help fix nitrogen from the air and make it usable to plants. Planting inoculated seed – whether you inoculate it yourself or purchase pre-inoculated seed – reduces the amount of nitrogen fertilizer needed, ultimately saving you money on fertilizer application. The benefit of buying pre-inoculated seed is that it saves you the hassle of inoculating the seed yourself.
Calculating pure live seed (PLS)
Now that you know the importance of reading the seed tag before purchasing seed, you can now think about calculating PLS. All the information you need is right there on the tag. Using the example seed tag below locate the two items labeled “PURE SEED” and “GERMINATION”.
Our example is 98% pure seed, meaning in a 10 lb bag there are 9.8 pounds of pure iron-clay cowpea seed. The next number we will need is the germination rate; this will also be indicated as a percentage. Our example has an 85% germination rate.
To calculate percent PLS for this seed, multiply pure seed and germination and then multiply by 100 (example below). The result is the percentage of pure live seed for this bag of seed.
98% pure seed
85% germination
(0.98 x 0.85) x 100 = 83% (Percent PLS)
We now know that 83% of our bag is iron-clay cowpeas capable of germinating. Now that we have the PLS of our seed we can calculate the amount (lbs) of pure live seed in our bag. To do this, multiply the bulk seed weight by the percent PLS.
50 lb bag x 0.83 (Percent PLS) = 42 lbs PLS
For example, a 50 lb bag would equal 42 lbs of iron-clay cowpea seed that will germinate.
Determining bulk seed rate
Using the percent PLS information we can also find the amount of bulk seed necessary to plant at a recommended seeding rate. To do this, take the recommended seeding rate for your planting method and divide it by the percent PLS of the seed you are using (example below). The result is the bulk weight that you will need to plant per acre to achieve the recommended seeding rate.
50 lbs/acre = recommended seeding rate for iron-clay cowpeas when drilling
0.83 = percent PLS of seed being planted (from example above)
50/0.83 = 60 lbs/acre
In order to plant a cowpea food plot at the recommended rate of 50 lbs/acre, we will need to plant 60 lbs/acre from this particular seed bag.
Another benefit of calculating pure live seed? Comparing seed prices
Not all seeds are of the same quality. Some have lower pure seed and germination rates than others. For this reason, it is not always most cost effective to buy the cheapest bag of seed on the shelf. If you wish to compare pure live seed prices between seed bags, first divide the price of the bag by the weight of the bag. This will give you the price per pound of bulk seed (example below). Now divide this price per pound by the percent PLS of the seed. The result is the price per pound of PLS.
Seed Manufacturer X 10lbs
Pure seed 97%
Germination 92%
Price $33
PLS (0.97 x 0.92) x 100 = 89%
$/lb (bulk) 33/10 = $3.30/lb
$/lb (PLS) 3.3/0.89 = $3.70/lb
Seed Manufacturer Y 10lbs
Pure seed 91%
Germination 82%
Price $30
PLS (0.91 x 0.82) x 100 = 74.%
$/lb (bulk) 30/10 = $3/lb
$/lb (PLS) 3.0/0.74 = $4.05/lb
According to these calculations, seed manufacturer X is actually a better value than Y. Using this process, especially when purchasing seed in bulk, you can be a practical money saver.
Let’s Plant
Now that you know what all those numbers on the seed tag of your favorite food plot seed mean and you know how to calculate PLS, you will be able to plant your food plots at the most effective rate possible. Remember, regardless of whether you are planting acres of soybeans with a no-till drill or frost seeding a ½-acre clover patch, knowing how to calculate PLS will allow you to be more successful and save money when planting food plots.
Other Resources:
Seed Fillers and Carriers for Planting Native Warm-Season Grasses and Forbs, Detailed Resource, Purdue Extension-FNR
Renovating Native Warm-Season Grass Stands for Wildlife: A Land Manager’s Guide, free pdf download
VIDEO: Calibrating a No-Till Drill for Conservation Plantings and Wildlife Food Plots
VIDEO: Frost Seeding to Establish Wildlife Food Plots & Native Grass and Forb Plantings
Moriah Boggess, former Purdue Extension Wildlife Intern
Jarred Brooke, Purdue Extension Wildlife Specialist
A recent study in Costa Rica by scientists at Princeton University-Department of Ecology and Evolutionary Biology and the University of Pennsylvania-Ecology & Biodiversity showed how agricultural waste could help successfully remediate barren tropical forest sites.
A deal between an orange juice manufacturer and advisors for the Área de Conservación Guanacaste was struck that allowed 1,000 truckloads (12 metric tons) of orange peels and pulp to be unloaded on nutrient-poor soils dominated by invasive grass within one of Costa Rica’s national parks in the mid-1990s. The land was left to rest for sixteen years. Now, the forest has begun the lengthy process of regeneration and some secondary forest regeneration has been observed. The peels were spread over 3 ha (7 acres) and scientists measured an increase of 176% in aboveground biomass. The distinction between the orange-fertilized land and the unfertilized areas was pronounced. Orange-fertilized areas demonstrated more tree biomass and species diversity and richer soils than their counterparts.

To enlarge photo click on image. Photo credits: Tim Treuer, Daniel Janzen, Winnie Hallwachs, & Leland Werden.
This research shows what could happen when the environmental community and industry find a medium where they can work together to come up with problem solutions. Perhaps, in future, similar uses can be found for agricultural excess here in the United States.
References:
Treuer TLH, Choi JJ, Janzen DH, Hallwachs W, Peréz-Aviles D, Dobson AP, Powers JS, Shanks LC, Werden LK, Wilcove DS. (2017) Low-cost agricultural waste accelerates tropical forest regeneration. Restoration Ecology, DOI: 10.1111/rec.12565
Resources:
Indiana Forestry & Woodland Owners Association
Purdue Extension-Forestry and Natural Resources workshops
Forest Improvement Handbook, The Education Store, Purdue Extension resource center
Shaneka Lawson, USDA Forest Service/HTIRC Research Plant Physiologist/Adjunct Assistant Professor
Purdue University Department of Forestry and Natural Resources
Wild animals have a dispersal period where young move on to new ground to establish their own home range. This is nature’s way of mixing the gene pool. It also allows for species to reoccupy small, isolated habitat patches. Late summer and early fall is a common time to see juvenile snakes because of dispersal.
Snake identification questions are one of my most common that I receive from the public. Usually, people want to know if the snake is venomous or not. Most snakes in Indiana are not venomous. In fact, there are only four venomous species in Indiana. Their distributions are generally limited.
The snake pictured here to the right is a Northern Watersnake (Nerodia sipedon). Photo and identification request was submitted to our “Ask an Expert” web submission by Mr. R. Dearing. While only about a foot long here, adults can reach several feet in length. Coloration in them is variable, but they typically have dark bands on a lighter tan or brown background. The bands are complete towards the head and fragment towards the tail. This little snake found its way into Mr. Dearing’s house. Fortunately, he was able to catch it and return it to the creek behind their house—which explains why it was there in the first place.
Resources:
Snakes and Lizards of Indiana, The Education Store, Purdue Extension
How can I tell if a snake is venomous, FAQs, Purdue Extension-Forestry and Natural Resources
Indiana Amphibian and Reptile ID Package, The Education Store, Purdue Extension
Ask An Expert, Purdue Extension-Forestry and Natural Resources
Brian MacGowan, Extension Wildlife Specialist
Department of Forestry & Natural Resources, Purdue University
Students in Forestry and Natural Resources (FNR) continue to volunteer for Hands of the Future, Inc., a non-profit program whose mission is to help educate children about the outdoors and natural resources. As this program continues to grow, one of their dreams has been to find woods to create a children’s forest. To have a natural site that has been embellished upon with children’s needs in mind and to encourage outdoor play and adventures.
The students plan on transforming 18.8 acres of idle woods into Zonda’s Children’s Forest. The children’s forest will be composed of six main areas:

Donations:
Donations to help make Zonda’s Children’s Forest a reality can be made here. They have six months to raise $235,000 in order to purchase the woods.
Volunteers & Interns:
Older students and adults can apply to be a volunteer. Volunteers are always appreciated, no past experience necessary. If you love nature and kids you will enjoy this program. Internships are available for college students, contact Zonda Bryant.
Resources:
Family Nature Clubs in Indiana – Indiana Children and Nature Network
Zonda Bryant, Director
765.366.9126
director@hands-future.org
If you or someone you know loves to learn about wildlife, especially reptiles and amphibians, then you will be interested in our new special offer package. We are offering our complete collection of reptile and amphibian field guides (4 softcover books) for 10% of the price of each individual book. These books cover all of the reptiles and amphibians that are found in the state of Indiana. They include detailed physical descriptions, distribution maps, and interesting information about the ecology of each species. All of the included books have been peer-reviewed by experts in the field of herpetology.
The Indiana Amphibian and Reptile ID Package can be purchased from the Purdue Education Store for $36.00.
Additional Resources, The Education Store, Purdue Extension:
Frogs and Toads of Indiana
Salamanders of Indiana
Snakes and Lizards of Indiana
Turtles of Indiana
More Resources Available:
Help the Hellbender, Purdue Extension
The Nature of Teaching, Lesson Plans K-12, Purdue Extension
Nick Burgmeier, Research Biologist and Extension Wildlife Specialist
Purdue Department of Forestry and Natural Resources
‘Twas the day before Arbor Day, when all through the park
Not a creature was stirring, no chirp, squeak, or bark;
The birds were perched on the utility wires with care,
In hopes that many trees soon would be there;
All types of squirrels, gray, fox, and red;
Had visions of oak trees dancing in their head;
And mamma with her overalls, and I my work jeans,
Were prepared and ready to make the park green,
When out in the park there arose such a clatter,
I sprang to my window to see what was the matter.
Away out my door I flew like a flash,
Running to the crowd that was gathered ‘round the ash.
The dead looking tree with no leaves to show,
Gave a glimmer of midday through its branches to objects below,
When what to my wondering eyes came ‘round the corner with ease,
But a miniature truck and in the bed, eight tiny trees,
With a little old driver so lively and quick,
I knew in a moment it must be Mayor Nick.
The trees looking so healthy and flourishing as they came,
He whistled, and shouted, and called them by name:
“White Oak! Red Cedar! Silver Maple and Black Cherry!
Cottonwood, Black Walnut, American Beech and Hackberry!
It is time to grab your gloves, shovels, and spades!” He did call,
“Now plant away! Plant away! Plant away all!”
With his blueprints out he started to show,
Where in the park each tree would go;
So excited and anxious with all my gear I flew
To the truck full of trees, and Mayor Nicolas too.
And then, in a moment, I heard on the road
The roaring of more trucks with trees overflowed.
As I lifted my head, and was turning around,
The city forester and many arborists came with a bound.
Mayor Nick had called in the professionals to help us out,
So we all would understand what this project was all about.
“Before we start planting, I want to explain
the benefits from these trees the city will gain!
Trees increase property value and improve living conditions.
They also relieve stress and help with CO2 emissions.
Better air and water quality, and sound barriers, too,
And the best part is the beautiful new view!”
After Mayor Nick’s speech, the city forester stepped in
“Whose ready to plant some trees?” He said with a grin.
The crowd cheered and the project was now on its way
Making the park beautiful and green in honor of Arbor Day.
First thing we had to do, was remove the dead trees.
The park was originally filled with ash, which was a feast for EAB.
The arborists cut all the trees down one by one.
There was so much help, in no time the cleanup was done.
As we finally started planting, the professionals came around
Making sure we were putting the trees properly into the ground.
I learned that you cut and remove only 1/3-1/2 of the B&B,
Then, you check the roots, the most important part of the tree.
If the tree has spiraling roots, all four sides must be sawed,
So the tree’s way of nutrient uptake and anchorage is not flawed.
It is also important that the root flare is not below the soil line,
Many people tend to bury it, thinking their tree will be fine.
Before planting your tree, consider the tree’s full-grown size.
Improper planting can cause the tree to die otherwise.
I’m so glad I decided to volunteer today
I learned so much about planting trees the right way!
After countless hours of hard work and sweat,
Mayor Nick’s goals for the park were finally met.
He thanked everyone, and as he drove out of sight,
He shouted “Happy Arbor Day to all, and to all a good night!”
Arbor Day Paper, FNR-445 Urban Forestry Topics
Author: Erin Hipskind, BS 2016
Arbor Day is an annual observance that celebrates the role of trees in our lives and promotes tree planting and care. As a formal holiday, it was first observed in 1872, in Nebraska, but tree planting festivals are as old as civilization. The tree has appeared throughout history and literature as the symbol of life. Arbor Day celebrations for 2017 is on Saturday, April 29th. Check out activities around your area: Purdue Extension County Offices, Indiana Department of Natural Resources or Tippecanoe Soil & Water Conservation District.
Other resources:
Tree Installation: Process and Practices, The Education Store-Purdue Extension resource center
Tree Planting Part 1: Choosing a Tree – video, The Education Store
Tree Planting Part 2: Planting Your Tree – video, The Education Store
Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources
Professional arborists, horticulturists, including lawn and tree care companies, garden centers, and landscapers, require training in proper management techniques and pest control to better serve their customers and protect the environment.
The Professional Landscape Management School is a two-day workshop offered every winter to local commercial lawn and tree care companies, landscapers, nurseries, grounds managers, and garden centers. The topics chosen for the program are based on current trends and needs. I located speakers, created the program schedule and brochure, and advertised it to over 1000 professionals, using both print mail and email.
Purdue Commercial Nursery & Professional Landscape
This comprehensive written abstract titled Tools for Staging and Managing Emerald Ash Borer in the Urban Forest shares research gathered in an eight-year period with a variety of management strategies.
Advances in control can help municipal foresters save ash trees from emerald ash borer (EAB) [Agrilus planipennis (Fairmaire)]
in urban forests. Although ash trees of any size can be protected from this pest, cities often do not implement programs because they fail to recognize and act o incipient populations of EAB. In this study, researchers develop a model for predicting ash mortality over an eight-year period, and validated with data from the removal of >14,000 ash trees killed by EAB in Fort Wayne, Indiana, U.S. researchers then developed a sampling scheme to help foresters map their ash trees along the expected progression of ash decline. This model was then used to modify a web-based EAB cost calculator that compares discounted annual and cumulative costs of implementing a variety of management strategies. It was determined that strategies that most heavily relied on saving ash trees were less expensive and produced a larger forest than those strategies that mostly removed and replaced ash trees. Ratios of total discounted costs to discounted cumulative benefits of strategies that saved most ash trees were over two-thirds lower than strategies of proactive tree removal and replacement. Delaying implementation of an ash management program until damage would be visible and more obvious to the community (Year 5 of the model) decreased the cost–benefit ratio by <5%. Thus, delays that rely on the abundance of locally damaged trees to bolster community support do not necessarily diminish the utility of implementing a control strategy.
For full article: Tools for Staging and Managing Emerald Ash Borer
Resources:
Tree Doctor App, The App Store
Invasive Species – Indiana Department of Natural Resources (IDNR)
Ask an Expert – Purdue Extension-Forestry and Natural Resources
Indiana Invasive Species Council – Includes: IDNR, Purdue Department of Entomology and Professional Partners
Great Lakes Early Detection Network App (GLEDN) – The Center for Invasive Species & Ecosystem Health
National Invasive Species Awareness Week: February 27-March 3, 2017
Invasive Species Week a reminder to watch for destructive pests, Purdue entomologist says – Purdue Agriculture News
Cliff Sadof, Professor
Purdue University Department of Entomology
Matt Ginzel, Associate Professor
Purdue University Department of Forestry and Natural Resources & Department of Entomology
Woodlands provide a multitude of environmental (e.g., carbon sequestration, enhance water quality, wildlife habitat), economic (e.g., timber, wood products manufacturing, tourism), and social (e.g., recreation, aesthetics) benefits to Indiana residents. The sustainability of these benefits is strongly tied to stability of the resource. In Indiana, 75 percent of the 4.65 million acres of forestland is owned by families. Actions they take on their property can impact the benefits woodlands provide all Indiana residents. However, many do not understand available options or sources of assistance.
The Department of Forestry and Natural Resources, in partnership with many other organizations, helps produce and mail over 31,000 copies of the Indiana Woodland Steward to woodland owners three times each year. This 16-page, two-color publication includes in-depth articles on forest stewardship and health, invasive species and pests, wildlife habitat management, economics, and more.
Subscribers owned more woods (71.6 ac) for a longer tenure (33 years) than the average woodland owner in Indiana based on data from the National Woodland Owner Survey. As a group, they were also more active managers based on the proportion enrolled in assistance programs and who had a written stewardship plan. Fifty-four percent regularly utilized information from the Woodland Steward. In addition, 51 percent of respondents have implemented at least one practice they read about from The Woodland Steward, potentially impacting an estimated 1.2 million acres of forestland. His use of print media to communicate with woodland owners could be considered expensive, but clearly a large number of woodland owners regularly read and utilize the information making the average investment per landowner much lower.
Forest farming in North America is becoming a popular practice that provides short-term income for owners of new forest plantations while their trees reach maturity. This income diversification is particularly relevant for many of the Indiana hardwood plantations planted in the last decade, but will not fulfill their economic potential until 60–70 years from establishment. This free download publication titled Costs and Returns of Producing Wild-Simulated Ginseng in Established Tree Plantations, FNR-530-W, is the second in a two-part series aimed at analyzing economic opportunities in forest farming for Indiana forest plantation owners. The first study explores growing hops along the tree line of newly established forest stands, while this second study investigates producing American ginseng in older (20- to 30-year-old) forest plantations.
Resources:
Costs and Returns of Producing Wild-Simulated Ginseng in Established Tree Plantations, The Education Store, Purdue Extension’s resource center
Energy Requirements for Various Tillage-Planting Systems, The Education Store
Home Gardner’s Guide, The Education Store
Planting Forest Trees and Shrubs in Indiana, The Education Store
Kim Ha, Research Assistant
Purdue Agricultural Economics
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue Department of Forestry and Natural Resources