How To Take A Soil Sample For Soil Testing

how to take a soil sample

This Soil Sample Guide illustrates soil depths for reference to plant roots and gives step-by-step instructions for how to collect a soil sample.


Correct Procedure And Handling Of Your Soil Sample Is CRUCIAL To The Accuracy Of Your Soil Test Results!

Soil Depths For Soil Sample Taking For Soil Testing

Procuring a correctly taken and handled sample is crucial to the accuracy of your soil test.

Soil Samples must be taken directly from the major root zone of your problem area.

Soil Tests can only reveal what is in the physical soil you send us, not the surrounding areas.

To avoid errors and make things easier, be sure to fill out your lab form, your sample bag, and your return address on the shipping box first.

Make a map of your sample locations with a permanent identification systems. Future samples should be taken from these same locations. Using a GPS and marking co-ordinates, or using signs or markers is a great way to remember exact locations.

To make a representative composite lab sample you should take four samples from a specific area, even for small beds or areas.

If you seen no distinguishing differences or performance markers over a specific area of interest, send samples taken from multiple areas to insure adequate testing coverage. The larger the area, the more samples needed.

Where you see significant differences in plant quality, soil coloration, or growth performance, take samples from these areas and make separate composite lab samples. Don't combine samples from different conditions into one sample.

For problem areas confine the sample taken to the specific area such as the root zone around dying plants or heavily calcified or discolored soil. These samples should be taken at no more than four foot spacing.

Soil Sample Depths from the major root zone:

Lawns, Pastures and Turf should be zero to six inches.
Field Crops and Beds should be zero to twelve inches.
For Deep-rooted plants and longer-term evaluations, take a sample from 12" to 24" from the bottom of the first sample. Do not combine samples from zero to 12" depth with samples from 12" to 24" inch depth.
For Trees, take and keep separate four samples, 12" a sample, to 4' deep.

If you suspect salts or see calcification or distinct discoloring take your first sample from zero to six inches of depth, and then incremental samples of twelve inches down to four feet depth or bedrock. Do not combine these samples.

 How To Take A Soil Sample

Using a sample tool provides an easy and accurate cross section.

If you intend to do multiple samples many times over, the investment in a soil sample tool will greatly relieve your efforts.

If you do not have a soil sample tool, the goal is to take a uniform slice of soil from the top of the sample to the bottom of the sample.

With a spade shovel or trowel, dig a hole from the top to the bottom of the desired area to sample. Put the excess soil to the side.

Taking your shovel or trowel, shave the wall of the hole at a depth of one inch, from the top of the hole to the bottom.

With a hand shovel or hoe, cut and scrape excess soil in strips and discard from the sides. You want to end up with the center one inch wide strip of one inch thick soil, from top to bottom.

When digging your hole, if the soil is too dry, or loose or crumbly, shave short lengths of constant width, taking care to uniform samples of soil.

Be sure to include the top crust of the soil in the sample. It contains fertilizers and elements which are a part of the overall spectrum of the soil.

Put samples for specific areas in a plastic bucket and mix well. Break up large chunks and clods to achieve an even consistency.

If the soil is wet, muddy, or contains moisture significant enough to damage packaging or hinder mailing, please allow time for the sample to dry before packing and shipping. Do not dry the sample by placing it in the sun or exposing it to heat. Allow the sample to dry naturally in a sunless area.

Remove trash, debris, and foreign items such as branches, roots, stems, rocks, etc.

Put enough soil in your return bag to fill to the line, about two cups. Fold the top of the bag down to the front once over, and wrap ties around the rear to keep the bag closed.

Put your sample bag and your filled out lab form into the return shipping box. Do not put your lab form in the sample with the soil. Fold up the lab form as many times as required to place it into the box with the soil sample. When closing the box be sure to utilize the locking tab. The sample bag of soil will fit snugly into the box as it is designed to reduce shifting during shipment. You may tape up the ends of the packaging as needed. Apply adequate postage and declare the contents as a soil sample to your shipper.

Test frequently. Test after each crop for optimum management. Perform interim tests for sudden changes or specific areas of poor performance. Problem areas can be isolated to specific areas and should be marked and tested regularly in conjunction with overall testing.

Please contact us at 956-383-0739 if you have any trouble or questions regarding your soil sample.

The PDF is available for DOWNLOAD HERE.

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