How soil fundamentals support healthy plant growth 

Successful growth in soil relies on growers taking good care of the soil and the organisms within it.

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Key Takeaway

For millennia, soil has been the conventional growth medium for crops, with its composition fostering a diverse microbial community.   

Soil has a natural ability to buffer shifts in pH, thereby stabilising the solubility of nutrient ions. Different soils have varying pH values due to their composition, which affects the solubility of certain nutrient ions. It is essential to know that each crop has a different preferred pH range; therefore, measuring the pH of your soil before planting is crucial.   

Take good care of your soil and the organisms within it, and you will create an ecosystem that can be relatively self-sufficient. 

What's in my soil?

The composition of soil can vary, but the basic components are air, minerals, water, and a small amount of organic matter, all of which foster a diverse community of microorganisms. The mineral components of soil are the sand, clay, and silt particles within it.  

The different chemical compositions of these components can impact the retention of nutrients in the soil and their availability to the plant. This is known as the Cation Exchange Capacity (CEC) of the soil and is a method for quantifying soil fertility.

Clay and organic matter (hummus) are two common components that have a net negative charge and can attract and hold positively charged ions, which include most nutrient ions. Therefore, increasing their availability to the plant within the soil, so they won't be leached out, and assist the soil's natural pH buffering.

Build a stronger foundation with our grower’s guide to soil.

Role of moisture in soil

Enables nutrient uptake

Water dissolves nutrients into the soil solution, allowing plants to absorb them through their roots.

Drives nutrient movement

Water helps move nutrients through soil via mass flow and diffusion, supporting consistent delivery of essential elements.

Supports root function and growth

Adequate moisture maintains cell turgor for growth, supports root expansion, and reduces plant stress, helping plants access nutrients more efficiently.

How to measure soil with Bluelab tools

Grow in Soil or Substrate

Reliable measurement tools for growers working in soil, coco coir, rockwool, peat, and other growing media, from home gardening to commercial nursery cultivation.
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Learn why water quality is important for your soil here.

Testing pH, MC (Moisture Content), and EC (Electrical Conductivity) of soil

1

Bluelab Soil pH Pen

A handheld Pen to measure the pH and temperature of your soil directly in the root zone.
2

Bluelab Multimedia pH Meter

A handheld meter that comes with a Multimedia Leap pH Probe to measure the pH of your solution, soil, or any growing media.
3

Bluelab Pulse EC/MC Meter

A handheld device that measures moisture, EC, and temperature directly to the root zone.

Common Questions

01

Where should I measure soil pH? 

Don't measure soil pH at the surface of the soil, or away from the root zone. The pH at the soil surface may be affected by accumulated salts, which can impact measurement accuracy. Measure close to the root zone and at the same depth to gain the most accurate picture of the growing environment.

02

Do I need to calibrate my Bluelab Pulse Multimedia EC/MC Meter? 

Yes, to have precise control over your growing environment. Different growing mediums have varying moisture retention characteristics. This is why calibrating your Pulse Meter to your specific growing medium is crucial for obtaining accurate readings and maintaining healthy plants.

03

What is the best pH soil tester?  

Bluelab offers a range of pH soil testers tailored to your needs, whether you are a hobbyist or commercial grower.

Ideal Soil pH and EC Ranges for Common Crops

Crop Optimal soil pH range Recommended soil EC (mS/cm)
Arugula 6.0 – 7.0 1.0 – 2.5
Asparagus 6.0 – 7.5 1.0 – 2.5
Basil 5.5 – 6.5 1.0 – 2.0
Beetroot 6.0 – 7.5 1.0 – 2.5
Bok choy 6.0 – 7.0 1.0 – 2.5
Broccoli 6.0 – 7.0 1.0 – 2.5
Brussels sprouts 6.0 – 7.5 1.0 – 2.5
Cabbage 6.0 – 7.5 1.0 – 2.5
Carrot 5.5 – 7.0 1.0 – 2.5
Cauliflower 6.0 – 7.0 1.0 – 2.5
Celery 6.0 – 7.0 1.2 – 2.5
Chilies 6.0 – 7.0 1.0 – 2.0
Corn 5.5 – 7.0 1.2 – 2.5
Cucumber 5.5 – 7.0 1.2 – 2.5
Eggplant 5.5 – 7.0 1.2 – 2.5
Garlic 5.5 – 7.5 1.0 – 2.5
Green beans 6.0 – 7.5 1.0 – 2.5
Kale 6.0 – 7.5 1.0 – 2.5
Leafy greens 6.0 – 7.0 1.0 – 2.5
Leek 6.0 – 7.0 1.0 – 2.0
Lettuce 6.0 – 7.0 0.8 – 1.8
Onion 6.0 – 7.0 1.0 – 2.5
Parsley 6.0 – 7.0 1.0 – 2.0
Parsnip 5.5 – 7.5 0.8 – 1.8
Pea 6.0 – 7.5 1.0 – 2.5
Pepper 5.5 – 7.0 1.0 – 2.5
Potato 4.8 – 6.5 1.0 – 2.5
Pumpkin 5.5 – 7.5 1.2 – 2.5
Radish 5.5 – 7.0 1.0 – 2.5
Rhubarb 5.5 – 7.0 1.0 – 2.5
Roses 5.5 – 6.5 1.0 – 2.0
Spinach 6.0 – 7.5 1.0 – 2.5
Squash 5.8 – 7.0 1.2 – 2.5
Strawberry 5.0 – 6.5 1.0 – 2.5
Sweet potato 5.5 – 6.5 1.2 – 2.5
Tomato 5.5 – 7.5 1.5 – 2.5
Watermelon 5.5 – 6.5 1.0 – 2.5
Yam 5.5 – 6.5 1.0 – 2.5
Zucchini 5.5 – 7.5 1.2 – 2.5

*Soil EC values are general guidelines and will vary with soil type, moisture, organic matter, and management. EC helps indicate nutrient availability and salinity balance, supporting healthy root development.

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