Why Soil Testing for Your Plants Matters: Understanding pH and Its Role in Plant Health

Plantcare.club
Jan 11
3 min read

Caring for houseplants isn’t just about watering them occasionally and hoping for the best. It’s about getting the details right—and one of those details is the pH of your soil and water. Whether you're new to plant parenting or a seasoned green thumb, understanding soil pH can make a world of difference in how your plants grow, thrive, or, well, barely survive.

So, what exactly is pH, why does it matter, and how can you test it at home?

Let’s dive in.

What Is pH? A Simple Explanation

The pH scale measures how acidic or basic (alkaline) a substance is. Think of it like a spectrum from 0 to 14:

0 to 7 = Acidic (think lemons or tomatoes)
7 = Neutral (pure water sits here)
7 to 14 = Alkaline/basic (soap and baking soda land here)

For most plants, the sweet spot lies between 5 and 8, though some plants have more specific needs.

Why Does pH Matter for Your Plants?

The pH of your soil directly affects the nutrients available to your plants. If the pH is too low (acidic) or too high (alkaline), your plants might struggle to absorb essential nutrients like nitrogen, phosphorus, and potassium—even if those nutrients are present in the soil. Think of pH as the key that unlocks your soil’s nutrient pantry.

Here’s a quick breakdown:

Too acidic: Plants can’t access certain nutrients, leading to deficiencies.
Too alkaline: Similar issue—nutrients get “locked up” and unavailable.

Keeping your soil in the optimal pH range ensures your plants can efficiently absorb everything they need to grow strong and healthy.

How to Test Your Soil’s pH at Home

While commercial growers use expensive equipment to measure pH, you don’t need to break the bank to get started. Here’s how to test your soil pH with basic tools:

1. Get a pH Tester

Affordable pH meters are available on Amazon or at garden centers. Look for one with good reviews, but don’t expect professional-grade accuracy.

2. Prepare a Soil Slurry

To get an accurate reading, you’ll need to make a “slurry” (a mix of soil and water).

Here’s how:

Weigh 50 grams of soil. - watch this Instagram video to learn how to collect the soil!
Add 100 milliliters of distilled water. (Distilled is key to avoid interference from minerals in tap water.) - Here is an Instagram video to help!
Mix thoroughly until it looks like wet mud.
Let the mixture settle, then dip your pH meter into the slurry.

Check out this Instagram post to learn how to test the soil.

3. Collect Soil Samples Correctly

Don’t just scrape soil from the surface! Roots dig deep, so your sample should include soil from all layers of your pot. Use a spoon to scoop soil evenly from the top to the bottom of your pot.

How Do Growers Manage pH in Greenhouses?

Professional growers monitor pH constantly. Depending on the water source—whether it’s rainwater, pond water, or well water—they may need to adjust pH levels using additives like:

Nitric acid to lower pH (if water is too alkaline).
Sodium bicarbonate to raise pH (if water is too acidic).

For home growers, adjustments are simpler. You can use products like pH-adjusting solutions or specialty soils to keep things in balance.

Finding the Right pH for Different Plants

While most houseplants are happy between 5 and 8 on the pH scale, some plants are pickier:

Petunias and Calibrachoas: Prefer slightly acidic soil (around 5.5–6.5).
Geraniums: Thrive in more neutral soil (6.5–7.5).

If you’re unsure about your plant’s pH needs, a quick Google search can help or ask us at PlantCare.Club!

Tips for Success

Distilled Water is Your Friend: Always use distilled water for pH testing to avoid skewed results.
Sample Evenly: Ensure you’re testing soil from all layers of your pot, not just the surface.
Don’t Overthink It: If you’re new to pH testing, start simple and aim for the general 5–8 range.

Your Plant Health Questions, Answered

Got questions about a specific plant or want to learn more about soil testing? Head to PlantCare.Club, where we’re passionate about helping you keep your plants happy and thriving. You’ll find blog posts, podcasts, and tons of resources to level up your plant care game.

So go ahead, give your soil a pH check, and watch your plants thank you with lush, vibrant growth! 🌿

If you have questions about caring for your plants or want to learn more about their unique journeys, don’t hesitate to reach out to us at plantcare.club.

Listen to our latest podcast episodes 👇