TL;DR: The right pH and EC levels depend on what you are growing. Keeping these within the recommended range ensures your plants can absorb nutrients efficiently.
What pH and EC mean
pH measures how acidic or alkaline your nutrient solution is. EC (Electrical Conductivity) measures how concentrated the nutrients are. Both affect how well your plants can take up what they need. For most herbs and leafy greens, a pH of 5.5 to 6.5 and an EC of 1.0 to 2.0 will serve you well.
Common plant ranges
| Plant | Type | pH range | EC range | PPM range |
|---|---|---|---|---|
| African Violets | Flower | 6.0 to 7.0 | 1.2 to 1.5 | 840 to 1050 |
| Basil | Herb | 5.5 to 6.5 | 1.0 to 1.6 | 700 to 1120 |
| Cucumber | Vegetable | 5.8 to 6.0 | 1.7 to 2.5 | 1190 to 1750 |
| Lemon Balm | Herb | 5.5 to 6.5 | 1.0 to 1.6 | 700 to 1120 |
| Tomato | Vegetable | 5.5 to 6.5 | 2.0 to 5.0 | 1400 to 3500 |
| Watermelon | Fruit | 5.8 | 1.5 to 2.4 | 1260 to 1680 |
How to monitor your levels
Use an EC meter to check nutrient concentration regularly. If levels are too high, dilute with plain water. If too low, add more nutrient solution. A pH meter or pH drops will tell you whether the solution is in the right range for absorption.