Water and Nutrients
What is pH and how will it affect my plants?
How do I measure the strength of my nutrient solution?
What is pH and how will it affect my plants?
The pH of the nutrient solution controls the availability of nutrients to the plant. Most plants grow quite well at a pH of 5.5 to 6.5. If your growing in a hydroponic system then pH is of the utmost importance as the solution is going directly to the plants roots and can cause problems very quickly. Different nutrients are taken in at different rates which can cause the ratios of nutrients to change causing changes to the pH level. If the pH falls below 5.5 or above 7 some nutrients will not be absorbed as quickly or efficiently as they should, which can cause deficiencies.
Simply by keeping an eye on the pH using a pH meter can make growing a lot easier and more efficient.
How do I measure the strength of my nutrient solution?
Nutrients strengths are measured by their ability to conduct electrical currents through a solution. Pure water conducts no electricity. The strength of the nutrient solution is measured in EC (Electrical Conductivity), CF (Conductivity Factor), PPM (Part Per Million), TDS (Total Dissolved Solids) and DS (Dissolved Solids).
As you can see there are a range of different ways of measuring nutrient strength. EC tends to be the most used in the UK and the American growers tend to use PPM to measure there nutrient strength. PPM is no where near as accurate or consistent as EC. Strangely enough PPM meters actually measure in EC and then convert to PPM. Unfortunately the two aren't directly comparable so the PPM reading is not precise.
An EC reading is just a measure of nutrient strength and cannot differentiate between nutrients. So even if you know your EC is correct it may still not be the right mixture. However there are full ranges of balanced nutrients to use these days.