PRACTICAL REFERENCE VALUES
Target pH and EC Values in Hydroponics
Which values suit lettuce, basil, tomatoes or strawberries? This page helps you interpret pH and EC as reference points for each crop and growth stage. It combines a filterable crop table with the fundamentals of nutrient solutions—from a small living-room system to a semi-professional greenhouse.
UNDERSTAND GUIDELINES · MONITOR TRENDS · RESPOND TO EACH CROP
There is no single perfect number
Start with a target range
pH and EC are control parameters for the nutrient solution. A target range is more useful than constantly chasing a single decimal value: plant species, cultivar, growth stage, light, temperature, water quality and system design all affect demand. The values in the table are therefore working ranges for an initial setting. The instructions for your particular nutrient line and the results of a water analysis take precedence.
Practical rule: Measure the source water, prepare the nutrient solution according to the product instructions, assess EC before pH, and then make only small, documented adjustments.
Interactive guidance
Filter crop values
Select a crop group or search for a plant. The table is deliberately concise: it supports planning but does not replace a crop-specific nutrient formulation.
| Crop | Group | pH guideline | EC guideline | Starting point for beginners |
|---|---|---|---|---|
| Lettuce | Leafy vegetables | 5.5–6.5 | 0.8–1.5 mS/cm | Start in the lower half of the range. |
| Rocket | Leafy vegetables | 5.5–6.5 | 1.0–1.8 mS/cm | Use a conservative level for young plants. |
| Pak choi | Leafy vegetables | 5.5–6.5 | 1.2–2.0 mS/cm | Monitor water level and temperature as well. |
| Basil | Herbs | 5.5–6.5 | 1.0–1.8 mS/cm | Prioritise stability over high concentration. |
| Parsley | Herbs | 5.5–6.5 | 1.0–1.8 mS/cm | Introduce changes gradually. |
| Mint | Herbs | 5.5–6.5 | 1.0–1.8 mS/cm | Record growth and water consumption. |
| Tomato | Fruiting vegetables | 5.5–6.5 | 2.0–3.5 mS/cm | Adjust by growth stage and climate. |
| Cucumber | Fruiting vegetables | 5.5–6.0 | 1.7–2.5 mS/cm | Account for water consumption in warm conditions. |
| Pepper | Fruiting vegetables | 5.5–6.5 | 1.5–2.5 mS/cm | Relate the value to growth stage and light. |
| Strawberry | Fruit | 5.5–6.5 | 1.2–2.0 mS/cm | Stabilise the root zone and temperature first. |
Guidelines compiled from university and extension sources; actual values may vary with cultivar, water and growing method. An EC within the target range does not prove that every nutrient element is present in the correct proportion.
The nutrients behind EC
Keep the chemical elements in view
| Group | Elements | Their role in the nutrient solution | How pH and EC relate to them |
|---|---|---|---|
| Primary nutrients | N · P · K | Growth, energy transfer and water balance. | EC measures their combined contribution alongside other ions; pH affects their availability. |
| Secondary nutrients | Ca · Mg · S | Cell structure, chlorophyll and protein building blocks. | Source water may already supply calcium and magnesium. |
| Micronutrients | Fe · Mn · B · Zn · Cu · Mo · Cl · Ni | Enzyme and metabolic processes in very small quantities. | Their individual contribution is barely visible in EC, but their availability can be highly pH-dependent. |
A practical workflow
From measurement to the next action
- Compare the valueRelate the reading to the crop, growth stage and your previous note.
- Narrow down the causeConsider water level, temperature, light and source water.
- Choose one adjustmentFollow the product instructions and work in small, traceable steps.
- Measure againAllow the solution to mix completely, then retest and document the effect.
There is no quick formula
A high or low EC alone is not a complete diagnosis. For recurring problems, hard water or larger reservoirs, a water analysis, crop-specific formulation and documented series of measurements provide a sounder basis.
Scalable practices
Living room, balcony and greenhouse
Living room
Choose one crop, mix a complete hydroponic fertiliser according to the label, and use a few consistent measurements to learn what a stable trend looks like.
Balcony
Heat, evaporation and rain alter the water level and concentration. Shade the reservoir, check values after weather changes and keep clear records.
Greenhouse
Crop zones, water analysis and defined measuring points create reproducible processes. Inlet and outlet readings reveal trends within the system.
Further reading