The Importance of Soil Testing Before Planting A Garden

Guest Post Author Bio: Henry Siregar is a gardening enthusiast. His other passions include the outdoors, travel and technology. He writes about his gardening interest over at his website GardeningJourney.com.

The Importance of Soil Testing Before Planting Your Vegetable Garden

When you decide to start a vegetable garden, you’re probably itching to start planting the seeds. You envision plump, juicy tomatoes growing alongside rows of staked beans hanging thick on the vine. Melons flower and produce the ever-popular watermelon. Nearby rows of Swiss chard and spinach are carefully shaded from afternoon sun to extend harvest time.

But, wait! One of the most important steps in growing great vegetables actually happens before planting. It is testing the soil where you plan to plant the garden.

The soil is a large part of what makes your vegetables grow, and testing it is a definite must for growing those great fruits and veggies. Not as much fun as planting and watching the plants develop, but imperative to the latter.

What is the Importance of a Soil Test?

Growing fruits and vegetables need nutrients to develop properly. While many of these nutrients come from fertilizer or compost that you add after planting, the roots absorb nutrients, as well as water and oxygen.

Root absorption is the key to feeding and watering the garden. Soil conditions must be appropriate for a good root system to develop. You'll hear the root system often mentioned while reading about soil tests.

A soil test lets you know which vitamins and nutrients are present in your existing soil. This includes major nutrients and micro-nutrients, all of which are important to the growth of your crops.

Photo courtesy of ag4impact.org

Photo courtesy of ag4impact.org

Planting a garden without first testing the soil is like driving a vehicle while wearing a blindfold. The results of your test advise which amendments you must add to get the soil ready for the optimum growth of your crops.

Your soil test may indicate the necessity of growing your garden in a different location. Should your sample find contamination with heavy metals, you should not grow food in the area. If your soil is highly alkaline, you would not want to plant blueberries or azaleas there without a lengthy amendment process.

These situations are not common but are something you learn from a soil test. Just a few things you need to know to safely plant and harvest food.

Other Measurements Reported by the Soil Test

A soil test measures soil pH, texture, and structure, as well as what nutrients are there and which are lacking.

It also examines the texture of the soil. Red clay soil most often needs compost to improve drainage, as does sand. Red clay holds water and drains too slowly, while sand has the opposite problem, drainage is much too fast.

The soil test also sometimes advises of how much compost the gardener should add.

Which Nutrients Are Lacking in Your Garden Bed?

Nitrogen, phosphorus, and potassium are primary ingredients in fertilizer. Some of these will be at an appropriate level in your existing soil. Other minor nutrients contribute to growth as well. The test reports scientific levels of boron, calcium, copper, magnesium, zinc, and manganese found in your soil sample.

Soil pH determines if your soil is acidic or alkaline. Most soils are in between, working toward a neutral point. The pH of the soil largely determines the vigor of your vegetables (how large and quickly they grow and produce).

Photo courtesy of pinterest.com

Photo courtesy of pinterest.com


Soil pH is measured on a scale of 1 to 14 with a measurement of 7.0 considered neutral. A number below 7 is acidic (sometimes called “sour”), and a number above 7 is alkaline (“sweet”). Most plants prefer nearly neutral soil with a pH between 6.2 and 7.2. Soil structure contributes to drainage and the ground room available to the plant to develop a good root system.

Results advise of what fertilizer you should use in your garden. Aside from wasting money by using unneeded fertilizer, over fertilizing with the wrong nutrients can diminish plant health and make them susceptible to pests and disease.

How To Get the Soil Ready for the Test

Take soil slices 6 to 8 inches deep from various areas in the garden location. Do this when the soil is relatively dry. Remove weeds, roots and rocks. You will need two cups to a pint of soil to send in for each soil test. Spread out the clean soil to dry for about 24 hours.

You can take the soil to the local county extension office or get the address to mail it in directly to the testing location. Sometimes it is best to take the sample in person, which provides the chance to meet the agent who may be helping you with any issues.

You may purchase a soil testing kit at a home improvement center or garden shop. Soil testing meters are available. Some tests include vials and tablets, along with a chart to explain your results.

When you get the results of the soil test, begin the amendment process as soon as possible. Once you get the soil right, let the growing begin. With proper soil, that vision of a spectacular garden will become a reality.

Resources & Further Reading

Clemson University Cooperative Extension’s Guide

Vegetable Gardening for Beginners: The Complete Guide

Soil and Soil Amendments Guide

BlogGiana Spear