Testing Garden Soil – Why Test Soil In A Garden

Testing Garden Soil – Why Test Soil In A Garden

By: Nikki Tilley, Author of The Bulb-o-licious Garden

Getting a soil test is a great way to measure its health and fertility. These tests are generally inexpensive, though well worth any cost when it comes to growing and maintaining healthy plants in the garden. So how often should you do a soil test and what does a soil test show? To answer these questions, it may help to learn more about the soil testing process in general.

Why Test Soil in the Garden?

Most soil nutrients are readily found in the soil provided that its pH level is within the 6 to 6.5 range. However, when the pH level rises, many nutrients (like phosphorus, iron, etc.) may become less available. When it drops, they may even reach toxic levels, which can adversely affect the plants.

Getting a soil test can help take the guesswork out of fixing any of these nutrient issues. There’s no need to spend money on fertilizers that aren’t necessary. There’s no worry of over fertilizing plants either. With a soil test, you’ll have the means for creating a healthy soil environment that will lead to maximum plant growth.

What Does a Soil Test Show?

A soil test can determine the current fertility and health of your soil. By measuring both the pH level and pinpointing nutrient deficiencies, a soil test can provide the information necessary for maintaining the most optimal fertility each year.

Most plants, including grasses, flowers, and vegetables, perform best in slightly acidic soil (6.0 to 6.5). Others, like azaleas, gardenias and blueberries, require a somewhat higher acidity in order to thrive. Therefore, having a soil test can make it easier to determine the current acidity so you can make the appropriate adjustments. It will also allow you to fix any deficiencies that may be present.

How Often Do You Do a Soil Test?

Soil samples can be taken at any time of the year, with fall being preferable. They are normally taken annually or simply as needed. While many companies or gardening centers offer soil testing kits, you can usually obtain a soil test for free or low cost through your local county extension office. Alternatively, UMASS Soil and Plant Tissue Testing Laboratory allows you to mail a soil sample in and they will send a soil report back based on your soil test results.

Avoid having the soil tested whenever the soil is wet or when it’s been recently fertilized. To take a sample for testing garden soil, use a small trowel to take thin slices of soil from various areas of the garden (about a cup’s worth each). Allow it to air dry at room temperature and then place it into a clean plastic container or Ziploc baggie. Label the soil area and date for testing.

Now that you know the importance of getting a soil test, you can better manage your garden plants by making the appropriate adjustments from your soil test results. Take the guesswork out of fertilizing by testing garden soil today.

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One of the most basic characteristics of soil is its composition. In general, soils are classified as clay soils, sandy soils, or loamy soils. Clay is nutrient-rich, but slow draining. Sand is quick draining but has trouble retaining nutrients and moisture. Loam is generally considered to be ideal soil because it retains moisture and nutrients but doesn’t stay soggy.

To determine your soil type, take a handful of moist (but not wet) soil from your garden, and give it a firm squeeze. Then, open your hand. One of three things will happen:

  1. It will hold its shape, and when you give it a light poke, it crumbles. Lucky you—this means you have luxurious loam!
  2. It will hold its shape, and, when poked, sits stubbornly in your hand. This means you have clay soil.
  3. It will fall apart as soon as you open your hand. This means you have sandy soil.

Now that you know what type of soil you have, you can work on improving it.


Success in the garden starts with the soil. It, as much as—and sometimes more than—moisture and sunlight, determines whether plants thrive or die. Here are a few quick and easy ways to test your soil.

Your soil needs to be able to provide nutrients to plants, and allow plants to take up the nutrients in the soil. Otherwise, your plants just won’t grow well.

The Peanut Butter Jar Soil Test for Sand, Silt, and Clay

This should take about 1 hour to set up and a full day to conclude. Find an empty straight-sided jar, such as a peanut butter or mason jar, with a lid, and have a ruler handy. Dig down to root level—about 6 inches—in the area that you want to test and remove enough soil to fill the the jar to between one-third and one-half full. Next, fill the jar to the shoulder with water, then set the jar aside to let the soil soak up the water. Put the lid on the jar and shake it hard for about 3 minutes.

  1. Set the jar down and look at your watch. In 1 minute, measure (with the ruler) the amount of sediment that has collected at the bottom. This is the sand in your soil.
  2. Wait 4 minutes more. Measure the sediment again: The difference between the two numbers will be the amount of silt in your soil.
  3. Take a third measurement in 24 hours. The difference between the second and third number will be the amount of clay in your soil.

Calculate the percentages of sand, silt, and clay, which should add up to 100 percent. Healthy soil typically consists of 20 percent clay, 40 percent silt, and 40 percent sand.

This simple test can help you to decide what to grow: If your soil is high in sand, it will be well-draining. Silt and clay are hard to get wet, but they stay wet plants that like “wet feet” would be happy here. Choose your plants accordingly and/or amend the soil:

  • If you have sandy soil, add humus or aged manure, peat moss, or sawdust with some extra nitrogen. Heavy, clay-rich soil can also be added to improve the soil.
  • If you have silty soil, add coarse sand (not beach sand) or gravel and compost, or well-rotted horse manure mixed with fresh straw.
  • If you have clay soil, add coarse sand (not beach sand), compost, and peat moss.

The Pantry pH Test for Soil Acidity or Alkalinity

  1. Place 2 tablespoons of soil in a bowl and add ½ cup vinegar. If the mixture fizzes, you have alkaline soil.
  2. Place 2 tablespoons of soil in a bowl and moisten it with distilled water. Add ½ cup baking soda. If the mixture fizzes, you have acidic soil.
  • If it does not react to either test, the soil has a neutral pH.
  • A very high or very low soil pH may result in plant nutrient deficiency or toxicity.
  • A pH value of 7 is neutral microbial activity is greatest and plant roots absorb/access nutrients best when the pH is in the 5.5 to 7 range.

Once you figure out your soil pH, you can change or adjust it. Acidic (sour) soil is counteracted by applying finely ground limestone, and alkaline (sweet) soil is treated with ground sulfur.

The Earthworm Test to Gauge Organic Matter

The best time to check for earthworms is in the spring when the soil’s temperature has reached 50°F and its surface is moist. Use a shovel to dig up about 1 cubic foot of soil. Put the soil on a piece of cardboard, break it apart, and look for earthworms. Learn more about the wonderful world of earthworms.

If your soil is healthy, you’ll find at least 10 earthworms!

If your soil has fewer than 10 worms, add more organic matter—compost, aged manure, leaf mold. Organic matter improves structure, slowly releases nutrients, and increases beneficial microbial activity.


Soil Testing and Amending (SoilTest)

UNL Extension – helping you turn knowledge into "know how"

Soil Testing & Amendments

submitted by Sarah Browning, UNL Extension Educator

If you're concerned about the soil quality in your landscape, whether it's your turfgrass, ornamentals or vegetable garden, a soil test can give you basic information to help you start improving it. Soil testing isn't very expensive or difficult to do and can be done anytime the soil is not frozen.

Start by locating a soil testing laboratory near you. Several labs are available in Nebraska including: AgSource in Lincoln, http://agsource.crinet.com , (402) 476-0300 and Midwest Laboratories in Omaha, http://www.midwestlabs.com/, (402) 334-7770. On their websites, soil testing can be found under "Agronomy & Feed" at AgSource and under "Agriculture" at Midwest Labs. Contact the lab or visit their website to request a soil sample test kit and submittal form. Testing costs approximately $15.00 per sample.

Decide how many soil samples are necessary for your landscape. One sample is usually sufficient for most landscapes unless there are obvious soil differences, then each unique area should be sampled separately. It can also be beneficial to sample areas separately based on their usage, so that samples are submitted individually for turf, ornamentals and vegetable gardens.

Create your soil sample by taking 10-15 soil cores from random locations within the sampling area. If you don't have a soil probe, you can use a shovel to collect samples at a 5-6 inch depth. Remove any vegetation or thatch from the soil cores and combine them all into one container. This aggregate collection of soil is your sample. Place 1 to 2 cups of well-mixed soil in a plastic bag or the sample container provided by the lab.

Choose a test that will give results for residual nitrogen, phosphorus, potassium, organic matter, cation exchange capacity (CEC) and soil pH. Your soil test results will usually arrive in about two weeks, along with recommendations for soil amendments in your landscape based on the plant types you indicated on the submittal form. If you have questions about reading the soil test results or potential soil amendments for your garden, call your local university extension office. To find your local office, visit office/locate.shtml

Tips for Soil Amending

  • Soil amending can be done in spring, but don't work the soil when it is wet to avoid soil compaction and the creation of hard clods. Fall is an excellent time of year for soil amending, because it allows time for the soil structure or chemistry to change before a new growing season begins.
  • Organic matter breaks down over time, so raising and maintaining your soil's organic matter content will require repeated amendment.
  • Keep in mind that Nebraska's clay soils have a high buffering capacity or the ability to revert to the original pH level after amendment with sulfur. Maintaining a lower soil pH will require repeated amendment.

Another great resource is the publication "Fertilizers for Vegetables in Home Gardens", which contains detailed information on adjusting soil pH, amending with organic matter and adding fertilizer.

This resource was added March 2011 and appeared in the Lincoln Journal Star Newspaper Sunday edition. For information on reproducing this article or using any photographs or graphics, read the Terms of Use statement

University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office


Get Started

Taking a Soil Sample

How to Submit HOME Lawn and Garden Samples

The Home Lawn and Vegetable Soil Test Mailer can be used to process any type of home soil sample (lawn, vegetable garden, tree, shrub, flower, and tree/small fruit). It is available through the MSUE Bookstore (opens in a new window). The cost of this mailer is $25 + shipping/handling fee. This mailer may also be available for pick-up at your local MSU Extension county office for $25. Click here to find a local county office (opens in a new window)

How to Submit COMMERCIAL Samples

Farm, landscape, lawn maintenance, nursery, athletic field and other commercial operations or those who wish to test soil for wildlife plots should contact their local MSU Extension office (click here for a list of county offices) or the Soil and Plant Nutrient Laboratory by calling 517-355-0218 or visiting www.spnl.msu.edu for soil testing instructions and costs.

When Will I Receive the Results?

You will receive an email (and text message if you opted-in) within 10 days after your sample is received at the MSU Soil Nutrient and Plant Lab letting you know your results are available at this website. A link directly to your report will be provided in the email and text message, or you can use the unique Report Code that is also sent.

If you submit your sample without an email address, it will take slightly longer for you to receive your results in the mail.


Soil Tests: When to Do Them, What Information You Learn and Who Performs Them

When should I do a soil test?

  • You haven’t done one in three years.
  • You just moved into a new place and don’t know much about the soil.
  • Your plant is struggling , and you suspect it may not have enough nutrients.
  • You want to see if the amendments you added had an impact.
  • You’re going to drastically expand your garden in three to six months and want to make sure your new plants perform well.

When is the best time to do a soil test?

If you suspect a problem, do it asap. It is easiest to do when the soil is not frozen. That way, you can begin to make changes as soon as you have the results.

Then, give the soil time to recalibrate. It can take a lot of effort to change poor soil. So, be patient and stick with it!

Who does soil testing?

If you need the results immediately, grab a soil kit test from your local home and garden store and DIY it.

Or if you can be patient, have a professional handle it because the results (provided by a lab) will often be more accurate and reliable. Many companies will do this for you as will your local Extension office .

Whether you buy a kit, go with a company or utilize your Extension office, it’ll be about the same cost (around $10).

But at Davey, we test the soil pH and do a soluble salt test for free. If you’d like something more in-depth, that will require additional fees. But since you only do soil tests every few years, it’s typically worth the extra investment.

What information does a soil test give you?

All the information you could ever want! Basic soil tests pinpoint the amount of organic matter, the pH and the level of macronutrients (nitrogen (N), phosphorous (P) and potassium (K)).

These standard tests only provide information on soil characteristics. That means they do not test for pollutants, pesticides or other potentially toxic compounds.

More advanced soil tests can detail more information – like your soil texture (whether it’s sand, silt or clay). You can also learn more about the levels of micronutrients–and there are a lot of those–or the biological activity in your soil! Finally, you can measure soil salinity, which is essentially how much salt is present. That’s smart to do if your plants are struggling.

With that info, you can figure out what amendments your soil needs.

Here are some common solutions:

  • Add more organic matter (like composted manure) to improve your soil. This almost always helps!
  • Most plants like a soil pH between 6 and 7. If your soil pH is too high, add sulfur, peat, or organic mulch . If it’s too low, raise the pH with a product containing lime. Remember: some plants prefer different levels of pH, so check before acting. And, of course, always follow the instructions on the product itself.
  • Add a fertilizer containing the nutrients your soil lacks.

Want us to test your soil? Click here to get started!

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Soil Testing - What Does A Soil Test Show - garden

**IMPORTANT UPDATE**
The lab is under new management! At this time, we cannot accommodate requests for expedited tests. Our turnaround time exceeds one month as of March 01 2021. We are closed to the public on fridays. Thank you for your patience.

The Soil-Water-Plant Laboratory analyzes soil, water, plant, sludge,В manure and miscellaneous types of samples from farmers, homeowners, consultants, government agencies and CSU personnel, and provides fertilizer suggestions for improving crop growth.В

THE LAB IS OPEN YEAR-ROUND
Our hours are 8-5 Monday-Friday
Except on and around major holidays.

**The Soil-Water-Plant Testing Lab does not test for pesticides or herbicides.**

Information and Forms: (Forms are in PDF format.)

  • Analytical Services Provided: list of services provided by the lab
  • Commercial Customer Information sheet: Customer Submittal Form with Chain
    of Custody
  • Lab Submission forms: (Please submit with sample)
    • Horticultural Applications for Gardeners (PDF Format)
    • Agricultural Applications for Farmers
    • Water Analysis
    • Forage Analysis/price list

Further analysis is available please contact the lab for more information and prices.В

Hints for Homeowners:

The Soil, Water and Plant Testing Lab offers gift certificates for soil tests!

Trying to figure out what to give the gardener, farmer or rancher in your life? The Soil, Water and Plant Testing Lab offers gift certificates for soil testing at only $35.00 per sample.

The test includes an analysis of pH, soil salts and nutrient levels in the soil as well as an interpretation of the results. Soil testing is a great way to evaluate salts, nutrient availability and the effects of adding composts or other amendments to the soil.

Gift certificates are always available and can be used at any time. Call Jim or Debbie at the lab at 970-491-5061 for more information.

Directions to our Building:

Colorado State University, Natural and Environmental Sciences Building, Room A-320, Fort Collins, CO. (CSU Map)

  1. North on College Avenue to Pitkin
  2. West on Pitkin (1 block) to Mason
  3. North on Mason (one way street) to "A" Street.
  4. West on "A" Street (1 block) to East Drive.
  5. At that stop sign you will be directly in front of our building.
  6. We are located in the south end of the building room A-320.
    Use the south entrance under the breezeway.
  7. There is a loading dock on the southeast corner of the building that can be used for short term parking as long as you park off to the side.
    The dock is across the corner from "A" Street on East Drive

The Availability of Parking for the Soil, Water, and Plant Testing LabThe three, 30 minute temporary parking spaces that were once available in front of the Natural and Environmental Sciences Building (NESB) have been eliminated and converted to a bus stop. This has been a problem for some of our clients who drop off samples for the lab. Alternative parking is available in the loading zones at the south end of the NESB and at the southwest corner of East Dr. and University Ave, just east of the Shepardson Building. The loading zone areas allow for a time period of 20 minutes. There are also two 30 minute parking spots on Mason St., just east of the General Services Building and a pay lot at the corner of Pitkin St and East Dr. just west of the motor pool. Unfortunately, the pay lot requires payment for a minimum of 1 hour.


Watch the video: soil pH test