Supplies for Mixing Kratky Nutrient Solution
You can mix a Kratky solution with very little equipment. This list covers what each item does so you can decide what you need. Start with the essentials and add the rest as you go.
Essentials
- A complete hydroponic nutrient. One-part or two-part, labelled for hydroponics, with calcium, magnesium and micronutrients listed.
- A way to check pH. Test strips or liquid drops are inexpensive. A pH meter is more precise but needs calibrating.
- pH down. Most growers need to lower pH after mixing. White vinegar works in a pinch (UF/IFAS).
- Measuring tools. Measuring spoons, a syringe or a measuring cup for liquids, or a small kitchen scale for powders.
- A lightproof container. Opaque, food-grade, with a lid and net cups. Wider containers are better than taller ones so roots can reach the solution (UF/IFAS).
Strongly recommended
- An EC or TDS meter. The only way to know the actual strength of your solution. Note whether it reads EC, or PPM on a 500 or 700 scale.
- Calibration solutions. An EC standard (commonly 1.41 mS/cm) and pH buffers (commonly pH 4 and pH 7) keep meters accurate (Oklahoma State University Extension).
- A mixing bucket and stirrer kept only for nutrient solution.
Useful extras
- pH up, for when you overshoot
- A carbon filter, if your tap water contains chloramine
- A notebook or label tape to record the date, EC and pH of each batch
- Probe storage solution for a pH meter
Looking after your meters
Rinse probes after each use, calibrate regularly and store pH probes moist as the maker recommends. A meter that is out of calibration is worse than no meter, because it gives false confidence.
Sources
- University of Florida IFAS Extension. Set It and Forget It Hydroponics (HS1488).
- Dunn, B. and Singh, H. Oklahoma State University Extension. Electrical Conductivity and pH Guide for Hydroponics (HLA-6722).
