How to Shop for Food Plot Lime to Maximize Deer Nutrition

May 3, 2023 By: Kip Adams
food plot lime

Calcium oxide is its chemical name, but we’re deer hunters rather than chemists, so we’ll simply refer to it as lime. It’s like your buddy’s nickname – more personal, fun, and, well, understandable. That’s important with friends and especially with food plot lime. Lime can have magical powers in your food plots and old fields, and a little knowledge about its benefits and forms can help you choose and apply the best type for your situation.

Why Use Food Plot Lime?

In general, wildlife managers use lime to increase soil pH in deer food plots and to a lesser extent in old fields containing early successional forage and cover. Acidic soils are those with a pH less than 7.0 as determined by a soil test (a soil test is the necessary first step in improving food plot soil). Amending acidic soils with lime provides the following benefits:

  • Increases longevity of clover and alfalfa stands
  • Supplies calcium, an essential plant and animal nutrient, to the soil
  • Promotes favorable microbial activity
  • Increases soil structure
  • Most importantly, it increases the availability of the fertilizer you apply to the plants

Soils with a pH of 6.5 can use nearly 100% of the nitrogen (N), phosphorus (P), and potassium (K) fertilizer you apply. However, soils with a pH of 5.5 can only use about 75% of the N, 50% of the P, and 75% of the K fertilizer you paid for and applied. The remainder of that fertilizer is tied up in the soil and unavailable to the food plot crop you’re trying to grow. A soil test and appropriate amount of lime will correct this and have your food plot crop growing at its maximum capacity.

food plot lime
An inexpensive soil test is the first step in food plot fertility because it tells you exactly how much lime and fertilizer are needed. This test from Kip’s Pennsylvania hunting land shows soil pH is “below optimum” and calls for 3,000 lbs./acre of lime.

You can buy different types of lime. Each comes with its own advantage(s) and a vastly different price. In general, food plotters have three options: bulk ag lime, pelletized lime, and liquid lime. Let’s look at each.

Bulk Ag Lime

Bulk agricultural lime, or “ag lime,” is ground limestone that’s typically sold by the ton. It’s the cheapest of the three options. It varies in consistency from a fine powder to damp sand, so it must be applied with a drop spreader. These spreaders have a chain and paddle system in the bottom that pulls the lime onto a spinning wheel that spreads it. Ag lime cannot be applied with a tractor or ATV/UTV spreader like those used to apply seed and fertilizer. Instead, your local distributor will spread the lime with a special truck. Some distributors can loan you an aglime spreader loaded with the lime you ordered, and you can then tow it with your own tractor or truck.

Technically, there are two types of ag lime – calcitic lime and dolomitic lime. Your soil test shows you how much lime is needed, and it also shows you how much magnesium is needed. If no magnesium is needed, use calcitic lime. If magnesium is required, use dolomitic lime (see the soil-test report above). Both types will look the same to you and you’ll apply them the same way. Only your soil lab and your plants will know the difference.

Your soil test gives a lime recommendation in pounds per acre. This can range from none to 8,000 pounds or more depending partly on the acidity of your soil. This recommendation is based on amending your soil for three years for the crop(s) you intend to plant. Thus, you only need to test and amend your soil every three years, as long as you follow the lime recommendations. The maximum recommended amount to apply in a year is 8,000 lbs./acre. If your soil test calls for more, apply the remainder in year two.

food plot lime
Builk ag lime ranges in consistency from a powder to damp sand, so it cannot be applied with a gravity-fed spreader like you use for seed and fertilizer. Your lime supplier will provide a specialized spreader truck or trailer.

Check the Lime’s CCE

Your soil test recommendation is based on “calcium carbonate equivalent” or the neutralizing value of the lime. The CCE is essentially a measure of the lime’s ability to amend the soil pH, and different types of lime have different CCEs in different soil types. This is similar to different bags of clover having different germination rates and therefore different planting rates. Each lime product sold has a stated CCE. Whatever type of lime you buy, check the CCE to determine the actual amount of that specific type of lime needed to meet your soil test’s recommendation. 

Compared to the cost of bulk ag lime per acre, pelletized lime is two to three times more expensive, and liquid lime is 10 to 20 times more expensive.

For example, let’s say your soil test calls for 1,000 pounds of lime per acre. Remember, that rate is for 100% CCE. You call your local lime supplier and ask to see the analysis of their current supply of calcitic or dolomitic lime (whichever your soil test suggests you need). If you learn the neutralizing value is 95%, that’s pretty good, and it means you would actually need 1,053 pounds of that lime per acre to achieve your 1,000 lbs./acre soil test recommendation. Here’s the math

100 ÷ 95 = 1.053 x 1,000 pounds = 1,053 lbs./acre

Unfortunately, not all aglime has that high of a neutralizing value. You may find lime with a value of 70%. So, using that lime you would actually need 1,429 lbs./acre to achieve your 1,000 lbs./acre of CCE recommendation. 

100 ÷ 70 = 1.429 x 1,000 pounds = 1,429 lbs./acre

Conversely, dolomitic lime can have a CCE of over 100%, so you would actually apply less than the soil test’s recommended amount. It is common for lime with lower neutralizing value to be less expensive, so a little knowledge and homework on your part can ensure you’re applying the appropriate amount of lime at the lowest cost to you.

Fine, Medium and Coarse Food Plot Lime

Different limes react at different rates with the soil due to their chemical composition and how finely they are ground. Finer material reacts more quickly with the soil, and that’s why lime is measured and described by mesh size. This information is built into the CCE or neutralizing value for you, so you don’t need to calculate it. 

I just want you to understand that lime that is ground to a smaller size reacts more quickly, and it’s typically referred to as fine, medium and coarse sized. It’s important to realize that bulk ag lime contains both fine and coarse particles. That means you get both a quick and a delayed action with the soil, so the amendment lasts longer, and less frequent lime applications are necessary.

In general, I recommend you apply lime three to six months in advance of planting the food plot. This gives ample time for the lime to react with the soil and adjust pH to the desired acidity.

food plot lime
Pelletized lime is two to three times more expensive per acre than bulk ag lime, but it can be used in gravity-fed ATV/UTV spreaders, and you can buy it in small bags. This makes it practical for small, remote food plots.

Pelletized Lime vs Ag Lime

In the early years of the food plot boom, pelletized lime was all the rage because it supposedly adjusted soil pH faster. Is this true? How can you determine how it would compare to bulk ag lime? You already have this knowledge. Look at the pelletized lime bag for the neutralizing value just as you would for ag lime. 

Pelletized lime is simply bulk ag lime that’s been pressed into a pellet for ease of application. If the bag you’re looking at was ground very finely before being pelletized, then it will react more quickly with the soil. However, if it’s the same size as your local ag lime, then the reaction time will be similar. 

Unlike ag lime, pelletized lime can be applied with the same tractor or ATV/UTV spreader used to spread seed and fertilizer. That convenience comes with a hefty price tag though, as pelletized lime is often two to three times more expensive per acre than bulk ag lime. Pelletized lime is great for that quarter-acre hunting plot way back in the woods, but it’s prohibitively expensive for the majority of your food plots.

Liquid Lime vs Ag Lime

Liquid lime is the new pelletized lime in the food plot world as it is advertised to “amend the soil faster.” Since this product must be ground extremely fine to dissolve in solution and be applied as a liquid, this claim is true. The smaller particle size allows this lime to react faster with the soil. 

However, this product is often 10 to 20 times more expensive per acre than bulk ag lime! That means if ag lime costs you $50 per acre, liquid lime would cost $500 to $1,000 per acre. Also, since all the particles are so fine, you don’t get the longevity from the amendment that you get with ag lime. That means you need to apply lime more frequently. 

I hope this information helps you understand the benefits of lime and helps you choose the best type for your needs. Mostly though, I hope this information helps you grow better food plots and be a better deer steward. A little knowledge can go a long way, and that’s especially true when unlocking the magical powers of good ole calcium oxide.

About Kip Adams:

Kip Adams of Knoxville, Pennsylvania, is a certified wildlife biologist and NDA's Chief Conservation Officer. He has a bachelor's degree in wildlife and fisheries science from Penn State University and a master's in wildlife from the University of New Hampshire. He's also a certified taxidermist. Before joining NDA, Kip was the deer and bear biologist for the New Hampshire Fish & Game Department. Kip and his wife Amy have a daughter, Katie, and a son, Bo.