Hydroponic Conversions & Reference Hub
Convert EC to PPM (TDS), Celsius to Fahrenheit, liters to gallons, kilograms to pounds, PPFD to DLI, and flow rates between metric and imperial. Plus crop EC and temperature reference tables. The quick reference every hydroponic grower keeps open.
- Open formulas
- Bi-directional live math
- Peer-reviewed target tables
EC to PPM Converter (TDS)
Enter a value in either field. Most meters use the 500 (Hanna/US), 640 (EU/AU), or 700 (Bluelab) scale.
Temperature Converter
Nutrient solution temperature dictates dissolved oxygen capacity and root health.
Volume Converter
Liters to US gallons and back—useful for reservoir sizing and nutrient dosing.
Mass Converter
Kilograms to pounds and back—handy for dry nutrient salts and yield estimates.
PPFD to DLI Converter
Daily Light Integral (DLI) = PPFD × photoperiod hours × 0.0036. Critical for target light dosing per crop.
Flow Rate Converter
Liters per minute to US gallons per minute — for pump selection, NFT channel flow, and reservoir turnover math.
Air Flow Converter
CFM to m³/h for exhaust fan and ventilation sizing. Common grow tent fan rating conversion.
Quick Reference Facts
The conversions indoor farmers rely on every day, at a glance.
Reference Tables for Hydroponic Growers
Target EC and temperature values for common crops. Use the converter above to translate EC to your meter’s scale.
| Crop | EC (mS/cm) | PPM @500 | PPM @700 |
|---|---|---|---|
| Microgreens | 0.8–1.2 | 400–600 | 560–840 |
| Lettuce | 0.8–1.2 | 400–600 | 560–840 |
| Kale | 1.0–1.5 | 500–750 | 700–1050 |
| Basil | 1.0–1.6 | 500–800 | 700–1120 |
| Eggplant (Veg) | 1.2–2.0 | 600–1000 | 840–1400 |
| Strawberry | 1.5–2.0 | 750–1000 | 1050–1400 |
| Cucumber | 1.7–2.5 | 850–1250 | 1190–1750 |
| Bell Pepper | 1.8–2.5 | 900–1250 | 1260–1750 |
| Eggplant (Fruit) | 1.8–2.6 | 900–1300 | 1260–1820 |
| Tomato | 2.0–3.5 | 1000–1750 | 1400–2450 |
| Scenario | Target Range |
|---|---|
| Nutrient Solution (Most Crops) | 18–22°C (64–72°F) |
| Root Zone Ideal | 20–22°C (68–72°F) |
| Cool-Tolerant Greens | 15–18°C (59–64°F) |
| Warm-Season Fruiting Crops | 21–25°C (70–77°F) |
| Root-Rot Risk Zone | Above 24°C (75°F) |
| Slowed Nutrient Uptake | Below 15°C (59°F) |
Frequently Asked Questions
What is the difference between EC and PPM?
EC (Electrical Conductivity) measures how well your nutrient solution conducts electricity, which directly reflects total dissolved mineral salts. PPM (Parts Per Million) is a calculated estimate derived from EC by multiplying it with a conversion factor (500, 640, or 700).
How do I convert EC to PPM?
Multiply your EC reading in mS/cm by your meter’s conversion factor: $text{PPM} = text{EC} times text{Scale}$. For example, $1.4 text{ EC} times 700 = 980 text{ PPM}$, or $1.4 text{ EC} times 500 = 700 text{ PPM}$.
Which TDS conversion scale should I use — 500, 640, or 700?
Use whichever scale your meter manufacturer specifies in its manual. Hanna and most US meters use 500; Bluelab supports 500 or 700; Australian and European meters frequently use 640 or 700. Comparing PPM across different scales causes errors up to 40%.
Why do two meters show different PPM for the exact same solution?
Because they use different conversion factors! One meter set to the 500 scale will show 700 PPM, while a Bluelab meter set to 700 scale will show 980 PPM for the exact same 1.4 EC liquid. Always compare raw EC (mS/cm) between growers to prevent confusion.
What temperature should my nutrient reservoir be?
Keep your reservoir water between 18–22°C (64–72°F). Above 24°C (75°F), dissolved oxygen (DO) levels crash rapidly, inviting Pythium (root rot). Below 15°C (59°F), phosphorus and root metabolism slow down severely.
Disclaimer: Target values are general guidelines—actual crop requirements vary by cultivar, environment, and growth stage. © MistCulture.com