The coco coir growing medium has somewhat unique fertigation requirements when compared with other soilless substrates. With countless coconut coir specific hydroponic nutrient brands available on the market it can be overwhelming when attempting to make a decision for your program. The good news is these products are quite similar, and made of the same base ingredients. The main difference between these are the branding and program-specific concentrations. Before choosing nutrients for coco coir, growers have multiple factors to consider.
Much like shopping for nutrient-dense food, it is important for growers to read the labels and look for the Guaranteed analysis of their nutrients. This is found on the label of any reputable product. Here the concentration of every macro and micro element contained in the fertilizer. After each macro and micro element there is a percentage. This number shows the overall strength of the fertilizer. Lower numbers mean you’ll go through more product to achieve a successful harvest. This is an important factor when calculating overall cost and margins!
Near Guaranteed Analysis manufacturers are required to list the fertilizer ingredients. Look for words to the effect of derived from. The derived from section can show the quality and efficacy of the product. Many include organic ingredients which are helpful in optimizing plant health but may be detrimental to irrigation systems. Stay away from products derived from organic sources such as kelp, humid acid, and leonardite. Applying these organic ingredients may lead to clogging drip emitters, buildup of biofilm in lines, and even issues with root rot. The plants can still receive benefits from foliar applications of these biostimulants.
Most coco coir specific nutrients come with two main bases, usually referred to as parts A and B. Part A is usually derived from phosphates and sulfates while Part B is from Nitrates and Calcium. These cannot be mixed together in concentrated form! While plants require all of these elements for healthy growth, mixing them together incorrectly causes the calcium to fall out of the solution, or “precipitate”, making it unavailable. This is why, no matter what product you use, it is important to precisely follow the mixing instructions.
While Coco coir is not only used for cultivating of high grade cannabis, coco coir specific fertilizers are. Fruit and vegetable growers understand the implications of coco coirs extremely high cation exchange capacity. They anticipate the increase in calcium demand and use a slightly higher concentration of calcium nitrate in their fertigation programs. These growers also monitor the nutrient levels in the coco coir regularly by testing samples of the substrate, leachate, and plant tissue. Enterprising fertilizer manufactures founded their brands of coco-specific nutrients by bottling these proven practices.
These days some of the most widely used nutrient brands in the cannabis industry are not specific to the coco coir growing medium. They instead have extremely simple 2 or 3 part formulas. These are easily tailored for coco coir by managing the concentration of each.
Neal Lund