Most growers run strawberries at an EC of about 1.0 to 1.5 mS/cm, lower for young plants. Strawberries are sensitive to salt, so it is safer to be a little weak than a little strong.
What EC Measures
EC stands for electrical conductivity. Dissolved nutrient salts carry current, so the more nutrient in the water, the higher the reading. It tells you how strong the solution is overall. It does not tell you which nutrients are present or whether they are in balance.
Targets by Stage
- Newly planted: about 0.8 to 1.0
- Growing and flowering: about 1.0 to 1.3
- Fruiting: up to about 1.5
These are working ranges, not exact rules. Watch the plant as well as the meter.
EC and ppm
Many meters show ppm instead of EC. The meter measures EC and multiplies it by a factor, and different brands use different factors. An EC of 1.0 reads as 500 ppm on one common scale and 700 ppm on another. If your meter can show EC, use that and the confusion disappears.
Why EC Climbs in a Kratky Container
The plant takes up water faster than nutrients, and water evaporates. As the level falls, the same salts sit in less water, so the reading rises even though you added nothing.
Bringing It Back
- Too high: top up with plain water.
- Too low: top up with nutrient solution.
- Several weeks old: replace the whole solution. EC can look fine while individual nutrients have run out.
Brown, crisp leaf edges are the classic sign that the solution has been too strong.
Related guide: Feeding Kratky strawberries.
