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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Successful growth in soil relies on growers taking good care of the soil and the organisms within it.
Shop Soil ToolsFor 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.
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.
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.
There are several ways growers can measure pH and EC in soil or substrate systems. Each method provides a different perspective on what is happening in the root zone.
Soil slurry testing mixes soil with water to create a measurable extract. It is commonly used for routine monitoring and comparing pH and EC trends over time. Read more about Soil Slurry Testing
The pour-through method measures leachate collected from the bottom of a container after irrigation. It is widely used in container-grown crops and fertigation systems. Read more about Pour-Through Testing
Direct measurement uses probes inserted directly into the soil or substrate to measure pH, EC and moisture in place, without removing a sample. Read more about Direct Soil Measurement
Bluelab offers a range of pH soil testers tailored to your needs, whether you are a hobbyist or commercial grower.
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.
| 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.
Learn how direct soil measurement with Bluelab helps growers monitor pH, EC and moisture directly in the root zone. This guide explains how direct measurement works, why moisture matters, and how to interpret readings over time.
Learn how the pour-through method helps growers measure pH and EC in container-grown plants. This practical guide explains how pour-through testing works, how to collect leachate, and how to interpret root zone conditions over time.
Learn how soil slurry testing helps growers measure pH and EC in soil and substrates. This guide explains what slurry testing measures, how to take a representative sample, and why consistency matters when comparing results.
Learn how to accurately measure soil pH to support nutrient uptake and healthy plant growth.
What do growers need to know for successful thriving crops? In this guide to soil for growers, we cover soil composition and more.
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