Overview

To mix proper nutrient solutions, there are several things that matter!

1. Nutrient Element Ratio (NER) Matters: Cannabis plants do best when given the correct ratios of nutrients. These ratios change during the course of the grow. Supplier feed charts allow you to get the correct NER. See our article, "Cannabis Fertilizers, Supplements, and pH".
2. Electrical Conductivity (EC) Matters: EC is a measure of the salinity of the water. It essentially is a measure of the overall strength of the solution. If the EC is too high, the plant cannot drink water and will show symptoms known as “nutrient burn”. Following supplier feed charts produces solutions that are too high in EC. See "Understanding EC, PPM & TDS for Growing Cannabis".
3. Order Matters: Adding nutrients in the wrong order can create lock out, which leaves the nutrients unavailable to the plant.
4. pH Matters: The pH of the solution affects the solubility of the nutrients. If the pH is out of the recommended range then certain nutrients will not be available to the plant.

This hybrid Article/Tutorial will explain the key factors involved with mixing nutrient solutions and provide specific instructions for how to create your own nutrient recipes and mix your own solutions that have the correct NER, EC, Order, and pH.

The NER and EC

As we explain in “Growing Cannabis in Coco with High Frequency Fertigation”, you always need to remember that fertigation requires a balance. You need to mix nutrient solutions that have the correct Nutrient Element Ratio (NER) and the correct Electrical Conductivity (EC). The only reasonable way to ensure the correct NER is to follow the supplier feed charts. All nutrient suppliers should provide a feed chart, and most of their published feed charts are specific to cannabis plants.

Unfortunately, it isn’t quite so simple as that. If you follow nutrient supplier feed charts exactly, you will produce a solution that is way too strong in terms of EC. We measure EC to make sure that the nutrient solution isn’t too salty. If water is too salty then plants cannot drink it and it can lead to dehydration even as they sit in water, just as you would dehydrate while drinking seawater.

To learn more about NER and Cannabis Fertilizers, read our article, “Cannabis Fertilizers, Supplements, and pH”.

To learn more about the importance of EC, read “Understanding EC, PPM & TDS for Growing Cannabis”, and to know what EC you should be aiming for, be sure to see our tutorial, “EC/PPM Targets for Fertigating Cannabis”.

Why do nutrient suppliers create recipes that are too strong?

Nutrient suppliers expect you to mix those doses to achieve the correct Nutrient Element Ratio (NER) and then to dilute the solution to arrive at your target EC or PPM. Therefore, they provide both recipes for NER and separate EC or PPM guidelines for strength.

The recipes are designed to be too strong because that allows each grower to dilute their solution to their individual target EC; while maintaining the correct NER. If the recipes were weaker than some growers needed, it would be more difficult to increase the strength of the solution without upsetting the NER.

When Mixing Nutrients, Always Remember:

• The feed chart recipes allow you to get the correct NER

• Measuring EC allows you to get the correct dose

Creating Personalized Recipes

Nutrient companies expect you to mix nutrients at the full doses and then dilute the solution until you reach your EC target. However, the base nutrients impact EC the most and many supplements have only a small impact on EC. Dilution reduces all nutrients and supplements regardless of their EC impact. For this reason, you should create your own nutrient recipe, by reducing the quantities of the base nutrients – but maintaining their ratios. This allows you to keep higher doses of certain supplements.

Always provide base nutrients at the ratio recommended by the feed chart: For example, if there is twice as much “Bloom” than “Grow” in the feed chart, there should be twice as much in your nutrient solution. The total amounts can vary to achieve your target EC, but the relationship among them should be the same.

When considering supplement doses, consider their EC impact: Some supplements, like humic acid, have a negligible impact on EC and they may be given at full the recommended dose. Other supplements, like bloom boosters, make a large impact on EC, and must be dosed carefully. Be sure to read our article, “Recommended Nutrient Supplements For Growing Cannabis” for a deeper look at supplements.

Coco For Cannabis Nutrient Recipe:

General Hydroponics Flora Series