The abbreviation EC stands for Electric Conductivity. The EC value represents the salt content – or the amount of nutrients in the soil or in the water – you’re giving your plants.
In this guide you will learn
You use three different types of fertilizers during the growing and flowering stage. During the growing stage, plants need a lot of nitrogen (N). To stimulate flowering, additional phosphor (P) and potassium (K) are often desired. The packaging of your fertilizers usually mentions the N-P-K ratio. The higher the number, the more content of that particular substance. You can derive from the ratio between N and P whether you’re dealing with growing fertilizer or flowering fertilizer.
We’re going to make a step-by-step nutrients solution. We want to end up with 2.5 gallons, with a modified EC and pH value.
Bergman’s Shopping List
Making a nutrient solution
- Bucket or barrel
- Measuring cups
- pH meter
- EC meter
- pH down nitric acid for growth and phosphoric acid for flowering
Bucket or barrel
Use a bucket or barrel that is larger than the amount of water you’ll be needing in order to prevent a mess. This also enables you to add some water if the EC is too high.
Use a basic grow fertilizer during the growing stage and a basic flower fertilizer during flowering. In addition you could use a root stimulator in the beginning and a booster during the end of the flowering stage. I use Flower Power nutrients but Fox Farm or Canna are also good. As long as they’re made for marijuana plants.
It’s always good to have different measuring cups. You can measure your nutrients, add some ounces of hot water or properly mix your nutrients solution. Buy a set of 5 measuring cups, ranging up to 32 ounces.
You have to add pH down to your water in order to modify your pH value. But since not even a drop of pH down is needed for every 32 ounces, it’s best to do this with a syringe. A 0.5 ounce syringe would be ideal.
If you want to know exactly what you’re giving your plants, you’ll have to lower the pH value to about 6. A pH meter works better than strips and is a must-have.
An EC meter measures the amount of dissolved salts (or amount of nutrients) in the water. You can’t see if it’s nitrogen, phosphor or potassium; it only shows the total amount of nutrients. If you’re using the right brand of nutrients, you’ll have the right ratio.
You can lower the pH with pH down. Having to lower the pH is common, because the pH of tap water is always high. pH down is nitric acid or phosphoric acid and can be bought in growshops, garden centers or at Amazon.com.
How to make a nutrient solution
Bergman’s step-by-step plan
- Fill the tank to three quarters with water
- Add nutrients until you have the desired EC
- Lower the pH of the water until desired
- Heat the water to 72 degrees F
Fill the water tank with preferably lukewarm water with a temperature of about 72 degrees F, so you won’t have to endlessly heat up the water later. Dependent on the EC value you wish for your plants, you measure the required amount of basic nutrients based on the user manual on the label and pour that into the water. Stir well. It’s best to track the amount of nutrients you add, so you can get an idea about what it does to your EC value.
Now you’ll have to check whether there’s enough nutrients in the water. The amount of nutrient salts is measured with the EC meter. If there are not enough nutrients in the water and your EC is too low, you’ll have to dose more. If the EC value is too high, you’ll have to dilute nutrient solution with water to lower it again. Make sure you stir the tank well before each measurement!
It’s difficult to provide ideal values for the EC; common sense and good observational skills are your most important tools regarding EC. EC values depend on the grower’s preferences, the type of plants and the size of the plant.
For safety reasons, the value of young plants in soil can be set at about 1.0 and this value can increase to 1.8 and beyond for adult plants. Young plants in hydro can have a value of 1.5, and adult plants one of 2.5. Check out these growing schedules for a weekly step-by-step plan.
Now that you have a nutrient solution with the right nutritional value, you’ll have to check the pH and modify this if necessary. The pH has to be around 6.0. A pH value of 5.8 or 6.2 is also acceptable, but always try to keep it at 6.0.
To lower the pH of the nutrient solution you just made, you fill the syringe with pH down. Squirt a bit of this acid into the barrel and stir this very well into the solution before measuring the pH again. Keep repeating this until the pH is about 6. Once again, track the amount of pH down you used so you can lower the pH of the next batch much quicker. If your pH dropped too far, you can increase it by adding pH up to the solution. If you have to do this more than once, it’s better to make a new nutrient solution.
Setting the right temperature
You can circulate the water in the tank using a little circulation pump in order to prevent little creatures and diseases from occurring, and to keep the water nice and fresh. Let the nutrient solution sit for a bit before using it, so all substances dissolve, react and stabilize evenly. It can be a hassle to add the right amount of fertilizers to a full tank of water to get the perfect EC value. But at a certain point you’ll know exactly how much you should add to obtain certain values.
How to adjust nutrient water?
- In case of a too low EC – Add more fertilizer
- In case of a too high EC – Add more tap water
- In case of a too low pH – Add pH+ (potassium hydroxide)
- In case of a too high pH – Add pH- (nitric acid of phosphoric acid)