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Hydroponic nutrient targets by crop and stage
There's no single "hydroponic nutrient strength." Leafy greens want a lean, nitrogen-forward solution; fruiting crops want a richer mix with more potassium as they set fruit. Here's a starting-point reference for common vegetable and herb crops.
Hydroponic nutrient chart: EC and ppm by crop
Target ranges as a general guide for established plants. ppm values use the 500 scale (ppm = EC in mS/cm × 500); if your meter uses the 700 scale, see ppm vs EC explained.
| Crop | EC (mS/cm) | ppm (500) |
|---|---|---|
| Lettuce & leafy greens | 0.8–1.2 | 400–600 |
| Basil & soft herbs | 1.0–1.6 | 500–800 |
| Strawberry | 1.0–1.4 | 500–700 |
| Cucumber | 1.7–2.5 | 850–1250 |
| Tomato | 2.0–3.5 | 1000–1750 |
Most hydroponic vegetables and herbs grow best with a solution pH of about 5.5–6.5, where nutrients stay most available.
Targets shift by stage
Within a crop, the solution changes as the plant develops:
- Seedling / early: run EC at the low end — young roots are sensitive and high salts cause tip burn.
- Vegetative: nitrogen-forward to drive leaf and stem growth; raise EC toward the crop's normal range.
- Flowering / fruiting: for fruiting crops, shift toward more potassium (and relatively less nitrogen) to support fruit set and quality, often at the top of the EC range.
Watch EC drift, not just the starting number. If reservoir EC climbs over a few days, plants are drinking water faster than nutrients — dilute with plain water. If it falls, they're taking up salts faster than water. The trend tells you more than any single reading.
Crop has these targets built in
Pick your crop and growth stage and Crop sets the target profile, then calculates salt or branded-nutrient weights for your reservoir volume — with EC/pH logging and drift warnings. Targets drawn from Cornell and Penn State extension data. Pay once, no subscription, works offline.
FAQ
What EC should lettuce be in hydroponics?
Low — about 0.8–1.2 mS/cm (roughly 400–600 ppm on the 500 scale). Run the low end for seedlings so the salts don't burn young root tips.
What is the ppm range for hydroponic tomatoes?
Rich — about 2.0–3.5 mS/cm, or roughly 1000–1750 ppm (500 scale), shifting toward more potassium as the plant sets fruit.
What pH is best for hydroponic nutrients?
About 5.5–6.5 for most vegetables and herbs, where the most nutrients stay available to the roots.
Sources
- Cornell — A Recipe for Hydroponic Success (per-crop recipes)
- Penn State Extension — Hydroponics nutrient solutions
Starting-point ranges for vegetable and herb growing — adjust to your cultivar, climate, and system, and verify with your own measurements.