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Soil testing 101
soil
Understanding the soil is the first step to making sure everything is right for planting or continued growth. - photo by File photo

By Blake Carter

UGA Extension agent

Hey Effingham County! It is finally one of my favorite months of the year —OCTOBER!

Something about corn mazes, pumpkins, Halloween and harvest time just gets me excited.

Outside of these fun activities, it is also a good time of year to start thinking about your soils. A successful lawn, garden or crop is dependent on what it is growing on. Understanding the soil is the first step to making sure everything is right for planting or continued growth.

So why fall? Fall is the time I recommend because the lawns and gardens are usually drying out a tad and they are easily accessible. That being said, soil samples can be taken year round and should always be done before planting something new into the ground.

Fall also works well time wise as it takes roughly two to three months for lime to really work with the soil it is mixed with. Lime helps with the PH level in your soils, which is crucial to get into the proper ranges depending on the plants desired. That puts you right at the tail end of winter (February-ish) when we start looking at pre-emergent herbicides for lawns specifically. 

Now, if I was writing by the book, I would say you only NEED a soil sample from established, medium to high fertility, lawn and ornamental areas once every two or three years. As a personal recommendation, I would say once a year on lawns and ornamental areas and as needed/every year when planting gardens of vegetables and trees and things of that nature. That just helps you double check where your soil is at before going into a new growing season. 

Also, it helps me out as an agent because, if/when there is a problem, usually the first thing I will ask is what is your soil doing. That just helps me get a full picture of the issue.

Good news is the samples usually have results back within a week, sometimes longer depending on the workload at the lab at the time. The reports get sent to an email of your choice. 

Don’t have an email? No worries. We can put either mine or the office email as the recipient and then call you once we have the results.

If you ever need them printed out or any help walking through the results, I would be happy to help. Sometimes the fertilizer recommendations are kind of funky and you will not be able to find them very easily so we have to calculate them out or try to get as close as possible using a fertilizer that is more common. 

Also, I am going to go slightly off topic here, but just a heads-up, stay away from weed and feeds you can find at stores.

Killing two birds with one stone does not apply in this case, the weed and feeds apply herbicides with fertilizer at the same time. The problem is those two things, especially for lawns, do not always overlap when talking about the best time to apply each.

OK, tangent over, now back to soil sampling.

We have talked about when to sample and the time it takes to get those results back from the sample, but how do we take the sample? As the county agent,  I will, of course, come take the sample if asked to, but I am a “I need to do it myself to learn” kind of guy so I encourage y’all to try sampling yourself! It is super simple to do. There are four keys to sampling.

1. Sampling materials

2. Location, location, location

3. Sampling depth

4. Sampling procedures

First on the list is materials. Odds are you already have the materials you need minus our soil sample bags. 

You need a clean trowel, shovel, spade or soil probe and a clean container. (bucket, plastic bag, etc.) The sample bags can be picked up at our office.

How many sample bags you need depends on the next key, location. Location matters when sampling soils. For homeowners, it is a little easier than someone with a 200-acre field. 

I always say map out a sketch of your land that you want to sample. Plot on that sketch where the plants you will be growing are located or if you are wanting to know why half your grass is yellowing and the other is not, plot the yellow dots on one half the sketch and none on the other half. Basically this helps you keep the area sampled straight in your head and lets me know exactly what needs to be in that area for the plants to succeed.

You can divide the land based on plant or by condition as mentioned above. Just make sure whichever you choose you let that be consistent across the board. 

On the soil sample bag, there is a spot for “Sample I.D.” and one for “Crop.”  After separating the area of land up (it can be as simple as front yard and back yard or just 1 and 2) that is what you will put on the Sample I.D portion of the bag. The Crop portion will be what you want to grow there. 

These two pieces of information are crucial for us to make sure we are getting the most accurate recommendation to you. On our end, we can code each sample for up to five different crops or plants. 

Lawns are the trickiest. We have some codes for established lawns and also codes for establishing lawns. The nutrient and pH requirement for those can be slightly different so if you are getting your lawn tested be as specific as possible!

Depth and the procedure for collecting go hand and hand. For lawns the sample depth is four inches, and for basically everything else the depth is six inches. The procedure is straight forward. 

UGA has a very technically worded procedure on its free publication “Soil Testing For Home Lawns, Gardens and Wildlife Food Plots,” but I like to reword that to be less fancy with the terminology. Take your tool of choice — I use a trowel when I do not have my soil probe with me — and push back grass or thatch on the top so you have direct access to the soil. Then take your hand shovel and make a scope to the depth you need. 

That scoop can be put in a clean bucket until you have sampled 8-10 times from a location or 6-8 spots around the drip-line of trees and shrubs. You may want to only put half a scoop actually into the bucket since 8-10 scoops is a lot of soil that you actually will not be sending off.

You then take those scoops and mix them together and if the soil is moist let it dry out. Please do not bring me a wet paper soil bag of mud. UPS does not like when the packages they carry leak. Once mixed well and dried, fill the soil sample bag to the line. ap the bottom of the bag to make sure the soil is compacted to ensure you have enough in the bag. 

A little too much is never a bad thing. Bring the filled out sample bags to us with a check or cash and we will take it from there. Each sample costs $8 here in the county, but that varies from county office to county office.

That is all folks. Iif you check those keys off your soil will be setting you up for success. I hope some of this helps clear up any questions y’all had on soil sampling, and also encourages you to get one done if you have not!


Joke of the Day: What did one carrot say to the other? “You are my SOIL-MATE!!”

I had another soil joke, but I figured it was a tad too DIRT-y to tell.


If you have any questions, suggestions, or want further information, please give me a call at or stop by the Effingham County Extension Office, (912)754-8040, 501 N. Richland Avenue, Rincon Ga., 31326.