What Are Soil Test Kits?

W hether you grow flowers in your garden or lean towards growing produce, your soil’s health is a crucial component of outdoor gardening. Most gardeners and farmers will state the importance of a proper soil test kit before you begin planting your seedlings. But what are soil test kits exactly, and how can they help you grow better and healthier plants?

Soil Test Kits 101

Soil test kits provide you with all the things you need to test your soil’s overall health. A soil test kit is an all-in-one solution; if you purchase one, you’ll find everything you need to test your soil’s contained within it.

A typical soil test kit usually includes the following components:

• Soil sample capsules for testing.
• Mixing chambers for the samples.
• A dropper.
• A color comparison chart.
• Plant pH preference information.
• Additional instructions to alter soil composition.

Some kits may not include droppers or plant pH preference information. Don’t worry. As long as you get capsules, a mixing chamber, and a color comparison chart, you’ll still be able to test your soil’s overall health.

What Soil Test Kits Test For

There are two main things that soil test kits check for in a soil sample: Nitrogen, Phosphorus, Potassium (NPK) content, and pH levels.

Soil pH Levels

The soil’s pH levels rank on a scale ranging from 4.5 to 7.5. Different flora has different preferences, so you may need to decrease (acidify) or increase (basify) your soil’s pH content depending on the plant you’re trying to grow.

Though most plants comfortably grow between the 6.5 to 7.5 pH range, some flowers such as magnolias or camellias thrive in acidic soil alone. Keep that in mind before you grow something in your soil.

Soil NPK Levels

Nitrogen, Phosphorus, and Potassium (NPK), along with oxygen, carbon, and hydrogen, are the macronutrients plants need for their growth. The plant acquires oxygen from water and the air, hydrogen from water, and carbon from CO₂ in the air. However, the only way for the plant to acquire NPK is from the soil.

Although not the same, you can imagine NPK to be similar to proteins, carbohydrates, and fats in human beings. Just as every human requires each of these macronutrients to some degree, plants also need a healthy amount of NPK to grow, flower, and fruit normally.

Every fertilizer, whether organic, liquid, or chemical-based, contains a mixture of NPK in different ratios.

Nitrogen

Nitrogen assists in plant protein production for new tissue growth. A lack of nitrogen may lead to stunted plant growth, whereas too much nitrogen may lead to abundant green foliage without fruit and flower production. Older plant leaves yellowing or fading away usually indicate a nitrogen deficiency. 

Phosphorus

Phosphorus helps with plant root growth. Additionally, it helps with flower production and improves the overall fertility of the plant. The soil needs a pH between 6.5 to 6.8 to properly absorb phosphorus. Soil organism activity generally helps with increasing phosphorus availability. Darkening around leaf edges is often a sign of a lack of phosphorus.

Potassium

Potassium stimulates carbohydrate production for the plant and improves its overall immunity and health. The nutrient also helps regulate the plant’s metabolic activity. A lack of potassium often leads to plant disease. Yellowing or browning leaves around the edges usually point to a lack of potassium.

Micro-Nutrients

Other than NPK, a plant also needs micronutrients for healthy growth such as calcium, magnesium, and sulfur. Calcium improves soil structure, magnesium helps produce chlorophyll for photosynthesis, and sulfur is an important plant protein component. Some soil test kits may also test for micronutrients in addition to the macronutrients.

Other Considerations

While a soil test kit is self-contained, you may still need some additional materials and tools to test your soil. These include a garden trowel, a clean bucket, and a plastic container. If you frequently garden or farm, chances are you already have these items lying around somewhere.

You should also remember that cleanliness is important for soil sample collection. You risk the chance of contamination of your sample and inaccurate results if you don’t clean your tools and equipment.

Finally, you should collect soil test samples from different areas in your garden that you will be using to grow similar plants. This will help ensure you get a more accurate result for your soil's health by preventing sampling bias.

What are soil test kits? Now you know and can ensure your plants get the best nutrients and soil conditions they need. Just remember the basics we’ve outlined in our guide, and you’ll be good to go!