The Five W’s of Soil Sampling
sampling can be a benefit to anyone that is trying to grow an item in the soil. This can be the person with a rose or vegetable garden. Soil sampling can also be for the farmer that is producing a crop such as corn or growing grass for grazing or hay production for livestock. I remember years ago Dr. Carl Hoveland giving a presentation to a room of cattle producers. In the beginning, he asked who was a cattle producer in the room. Hands went up all over the auditorium. Dr. Hoveland quickly stated that they should all consider themselves grass producers first since if they have the forage, the chances of making a profit on the livestock would increase. Again, soil sampling can be for the person that wants a great looking lawn, a better producing vegetable garden or a farmer that needs a quality yield.
What is the purpose of soil sampling? In a nutshell, soil sampling can help eliminate the guess work in how you need to handle the nutritional requirements of what you are growing. To be more exact, when you send a sample to the lab, we will code that sample for the goal of that area. It may be a hybrid bermuda lawn, a home vegetable garden, a flower bed or a fescue pasture. The purpose of coding the sample is to get more exact liming and fertilization recommendations for that soil area in relation to that goal. Sure, we have plenty of publications that will give general recommendations in regards to liming and fertilization, but a soil sample gives more accurate recommendations.
Where can you take a soil sample? I have basically already answered this one, but I would conduct a sampling procedure in areas that you need production for appearance or yield. Naturally, you may not take samples in a forest, but you should take a sample in a garden or in a hayfield. I will add that when moving to a new property or working a field for the first time that would be a good reason to soil test because you do not know what is going on under the soil surface. Remember, in Northwest Georgia we have a tendency to be more acidic or lower in soil pH. Soil pH is important for efficient use of fertilizer. For most items, we try to keep a soil pH in the 6.0- 6.5 range. When soil pH is lower, you can actually have a percentage of fertilizer that is never used by the plant or grass roots.
When can a person take soil samples for the UGA Soil Test Lab? Soils can be tested any time, but we suggest to allow enough time for the analysis and for fertilizer and lime application. We normally get results back from the lab in 5- 6 working days if not sooner. One reason to sample in a reasonable amount of time prior to an activity is lime. Lime is what improves or raises pH and it can react slowly so we suggest mixing lime at least 2- 3 months prior to planting. Fall is a great time to soil sample.
Our information suggests that once medium and high fertility levels are established you can sample lawns and ornamental spots every 2- 3 years. Vegetable gardens can be sampled every 1- 2 years.
Why should you soil sample? I think most county agents could be nicknamed the “soil sample person” by most clients. When a person is having a problem with an ornamental bed or crop, many times we will ask the last time that area has been soil sampled. Sometimes the problem can simply be a nutritional issue or a low pH slowing down the fertilizer usage. How do you take a sample? When you sample, you need to do a complete sampling procedure. We will send one pint of soil from your spot to the lab. Each sampling procedure is $ 9. You need a good representation of the soil area you are working with to get accurate results. Taking a pint of soil from one spot in the yard is not a good representation. You also need to take samples at the correct sampling depth for that soil use also.
For example, if sampling a lawn, you will need a digging tool and a plastic bucket. In a zigzag pattern go across the lawn and randomly stop 10 times. Each time push the tool down in the ground to 4 inches. Then push the handle forward to make a wide opening. Then from the side of the opening, cut a slice of soil that is ¼ inch thick, two inches in width and is four inches long from top of the soil surface down to the depth of the cut. Put each sample in the one bucket and then mix the samples when done. Collect a pint of the mixed soil for the lab. For gardens and ornamentals, sampling depth is 6 inches. For more information, contact UGA ExtensionGordon County or email gbowman@uga.edu.