The following are tools that can be used to test garden soil fertility.
To collect samples for soil testing the following tools will be needed. Use a stainless steel or chrome-plated soil probe, hand garden trowel, shovel or spade. Do not use brass, bronze, or galvanized tools because they will contaminate samples with copper and/or zinc.
Home Soil Testing Kit
The simple choice for soil testing tools is a home soil testing kit. These kits come with the necessary tools to test and read your soil’s fertility.
Take a soil sample. A home testing kit will provide some instruction on how to collect a proper sample. It’s not complicated! Simply dig up several samples from the area you want tested with a spade, getting thin sections of soil that reach at least 3 inches down for lawn and 6 inches down for garden areas.
Add all of the samples taken from the area of the yard to a container and mix them together until they break up and combine. Remove any large rocks or other non-soil particles from the soil.
Scoop up part of the mixed sample soil in the cup provided with the soil testing kit. The instructions that come with each specific kit provides guidance on how much soil you need to collect for each sample.
Insert the testing strip or indicator that came with the testing kit into the cup and allow the strip or indicator to sit in the cup for the amount of time indicated in the kit instructions. Normally, a soil testing kit requires a 24-hour time frame to show a result.
Get the reading from the strip or indicator. Consult the instructions that came with the kit, which usually provides direction on steps that you need to take to correct your soil if the test discovers fertility issues. For pH issues, read more at Understanding Soil pH.
Soil Probe or Auger
A soil probe or auger, available from mail order catalogs and garden or farm supply outlets, is the best tool for sampling. An auger will be needed if the soil is very stony or gravelly. Simply push the probe (or push and turn the auger) into the soil to the desired depth, lift up to remove the core, and place it in the clean pail. Sampling depth should be 4 to 6 inches deep for lawns, turf, or other perennial sod, or tillage depth (usually 6-10 inches) for annually tilled crops.
Garden Trowel or Shovel
If a soil probe or auger is not available, collect your sample by pushing the blade of a garden trowel, shovel, or spade into the soil to the desired depth. Cut out a triangular wedge of soil and set it aside (to be replaced after sampling). Now slide your blade into the soil again taking a thin (half inch) slice from one side of the hole. With a knife, trim the slice to about a 1-inch strip of soil down the center of the spade – top to bottom. Save this “core” as part of your composite lab sample.
The soil probe is the best tool for collecting soil samples. The soil probe works better than a shovel or trowel because this tool equally collects soil in a continuous core from the surface through the entire sampling depth with minimal disturbance of the soil. It also allows for faster sampling.
Some of the disadvantages of a soil probe are:
- it cannot be used when the soil is too wet because the soil compresses
- it cannot be used when the soil is too dry because it is difficult to penetrate the soil
Soil probes also do not work well in soils that contain gravel.
Soil probes are available through agricultural supply companies or your agriculture Extension agent may be able to help you locate a supplier. Cost is typically $35 or more.
Mix soil samples in a clean, plastic bucket. If the bucket has been used to hold fertilizer or other chemicals, wash and rinse it thoroughly before using it for soil samples. Even a small amount of lime or fertilizer transferred from the sampling tools to the soil can seriously contaminate the sample and produce inaccurate results.
In addition to these soil testing tools, if you plan to submit your sample to a Soil Testing Laboratory, you may need a Soil Sample Information Sheet and a Soil Sample Box. Both are available from your the extension office in your county or city. Look in the government pages of your phone book or extension office for the address and phone number of your local Extension office or buy your own soil testing products.
Before we proceed let’s check what you have learned about the proper equipment for soil sampling!