Hydroponic nutrients in the UK: choosing and mixing feed
Use a complete feed labelled for hydroponics and your water type or crop stage. Follow its label by volume, add parts separately to the reservoir and measure the result instead of copying an internet recipe.
The short version
Use a complete feed labelled for hydroponics and your water type or crop stage. Follow its label by volume, add parts separately to the reservoir and measure the result instead of copying an internet recipe. The useful test is not whether a method can work, but whether it keeps the roots supplied with water, dissolved nutrients and oxygen while the leaves receive enough light.
- Hard-water and soft-water versions account for different starting minerals.
- Concentrated A and B parts must not meet before dilution.
- More nutrient is not more growth.
A practical way to do it
- 1
Measure the reservoir’s actual water volume.
Make this change deliberately, then observe the plant and system before changing the next variable. That separation makes the result useful.
- 2
Add each part separately and mix thoroughly.
Make this change deliberately, then observe the plant and system before changing the next variable. That separation makes the result useful.
- 3
Check EC only after the solution is uniform.
Make this change deliberately, then observe the plant and system before changing the next variable. That separation makes the result useful.
- 4
Write down the dose and reading.
Make this change deliberately, then observe the plant and system before changing the next variable. That separation makes the result useful.
What to watch
Look at the whole system before diagnosing a single leaf. Check new and old growth separately, lift the lid to inspect root colour and texture, confirm that water or air is moving, and compare today’s readings with the last entry in your log.
Never combine concentrates in a measuring cup; insoluble compounds can form.
Make the setup easier to live with
Put inspection points where you can reach them without moving plants. Label cables, nutrient bottles and measuring tools. A waterproof tray, a marked full-water line and a simple notebook prevent more trouble than an elaborate controller. When a crop finishes, remove roots promptly and clean the parts you can now reach.
Questions people ask
What is the simplest way to act on this guide?
Measure the reservoir’s actual water volume.
What is the most common mistake?
Never combine concentrates in a measuring cup; insoluble compounds can form.
What should I record?
Write down dates, water volume, nutrient dose, pH and EC readings where relevant, plus one photograph. A short record makes patterns much easier to diagnose.
Sources
Checked 10 November 2026. Product labels and local conditions take precedence.
- Electrical conductivity and pH guide for hydroponics — Oklahoma State University Extension
- Hydroponics — Oklahoma State University Extension