Our main man Hydroguy works in a grow store somewhere in BC, Canada. He’s more or less seen it all, so who better to introduce novice growers to the vast array of products available at your local grow store? But this is no sales pitch, just straight talking and no nonsense. Take it away Hydroguy…
WORDS: Hydroguy
To all the consumers who find the sheer magnitude of the plethora of plant products bewildering: I feel your pain. To know nothing is sheer abysmal confusion, yet to know more does not seem to make product choice easier. When I see new growers walk into a store with a blank gaze I can actually observe their mental processes block as the overwhelming, yet exciting, stimuli flashes at them from numerous brightly colored bottles. This blank gaze often turns into a mix of confusion and skepticism. Too often novice growers think in terms of ‘Is it real or BS?’ whereas they should really be asking: ‘Do I need this?’ All products are of use in some or another application, it’s just a matter of finding what’s useful to you.
Base Hydroponic Nutrients
All organisms are elemental and require elements to live. We can look at our “vitamin/mineral” requirements as humans and it’s a short list. Plants have a similar “short list” and science has determined that, in order to technically survive, plants must get hold of them. Nitrogen, Phosphorus, Potassium (NPK), micro nutrients, etc. So these are the base survival needs. But to think of this as the limit of an organism’s needs is obtuse, just as a human would not have a great life eating cardboard for calories and taking vitamins. That said, whether your concern is simply production or quality of produce, you will need a base nutrient to supply the required minerals for growth. In the near-imperceptible chain of causality that affects plants outdoors, you have covered the most basic rudimentary needs. To qualify as a “base nutrient” all that is required are the N, P, and K in whatever ratio and micro-nutrients in sufficient quantity for your plant. Base nutrients are similar, but not the same. To arrive at a base nutrient (20-20-20 for example) a company can use various elemental compounds in combination; different combinations can have more or less purity at achieving the target mineral balance, and impurities are associated elements unintended for the outcome, such as arsenic. Aside from the ‘backpacked’ impurities in lesser quality products, different companies also use various arrangements of elemental compounds: for example, Calcium Nitrate or Ammonium Nitrate (among others) to provide the nitrogen. Different-sourced ingredients, as well as the final ratio of minerals, will all have slight variance in end use – those exact differences can be discussed another time.
Hydroponic base nutrients come in liquid 3-part, 2-part, and powder forms (”Why pay for water?”, some growers ask.) What you want is determined by preference, budget, availability, and trend. Read, ask your fellow growers, and inquire at your store to see what is buzzing – most base hydroponic nutrients are usable in any medium regardless of name. “Three part” can mean “use all three parts in conjunction” at different dilutions for each stage, or it can have one Grow and one Bloom for those respective stages and a third bottle added during both. “Two part” is often two parts for Grow and two for Bloom: four bottles mischievously pretending to be two. “Single part” is the actual two-part system with a Grow and a Bloom, or something representing those stages such as 20-20-20 and 15-30-15, and single part is also where you will find the “slurry” concoctions of mineral-based nutes with organics included. The ‘mineral/organic slurry’ is of some benefit to peat users since they add some cation exchange capacity (to be discussed later) to the inert peat without going all hippy.
“Well, I am using coco, so I need some coco food.” No, you don’t. Get better quality coco or add some cal/mag. Old coir was crappier because people didn’t realize the importance of desalinating it thoroughly, or some unscrupulous companies took the cheap route. Most coco-specific nutrients and only slightly increased in cal/mag and sometimes lessened in nitrogen – big whoop. If you are 100%-coco always then maybe it suits you, but I don’t see the importance.
There’s also the new “premium” base nutrients out there with labels donning expensive jewelry etc – these are still new to date for confidence, but if you’re willing to pay the piper for a trial there is some good buzz about some of them. As plant food becomes more of an organic chemistry art, we swerve less out of simple minerals and more into proprietary compounds we cannot know of even if we think we might understand them. That said, there still remains a need for disclosure and I can’t hold it against anyone for leaning to products with some transparency – in their attempt to avoid competitive replication, nutrient companies tend to alienate the consumer from understanding what their product is. Similarly, replication is a concern for consumers: nobody wants to add the same thing twice, and “just use it” is simply not convincing.
Organic Base Nutrients and Enhancers
The French Paradox. If you’ve never heard of it, pause to Google, but this is one example of a pretty basic point: there are more beneficial compounds in our food than simply vitamins. After the basic mineralogical requirements to sustain life, there are all the other bazillion compounds to improve the quality of life or, in our case, quality of produce of whatever form. An apple can technically minimally exist, or an apple can be packed with flavor, vitamins, and The Other Stuff (technical term – TOS). TOS represents turpines, flavonoids, organic acids, and a long list of stuff we don’t care to know of but still want to derive the benefits of. I don’t think it’s scientifically accepted that adding compost, kelp, guano, or another manure will increase the bio-active chemistry in produce, but “foliar feeding” isn’t accepted (in Canada) either – so my crutch is simple time-tested anecdotal observation: including organics will improve the quality of the end produce, thus increasing its flavor, aroma, and TOS.
Organic base nutes have come a long way in the last few years – mostly in convincing people they are worthwhile. We thought plants ate dirt, then realized they ate minerals from dirt (or water) – now it seems the geeks have decided that even larger organic compounds can make their way into the plants, such as vitamins. As always, it will always take science much longer to prove what people have been doing successfully for thousands of years, and continue to do today in “less advanced” areas of the world. The challenge for growers in the petrol world has been to match the yield of mineral nutes, and this has been displayed by various growers in enough circles to be generally accepted. It is a matter of substrate reuse and nurture, knowing what to add when – I will save details, but suffice to say if it is something you’re interested in it’s much easier today than ever, but still comes with a new learning curve.
Organics in hydroponics systems is something people would have balked at years ago; now there are products designed for such use. Growers have tested all forms of thick, organic sludge in their systems and, as much as commonsense still rules regarding buildup, slime clogs, and sugar coating, with a bit of elbow grease and absence of emitters or spaghetti hose many systems can run with nutrients not at all designed to be used in water gardens. The rigidity in this case is for generalization: you can’t tell everyone to do something that half will screw up. But, given the motivation and some knowledge, all these “can and can not” principles of growing can be realized as arbitrary guidelines. Beyond the liability of warranty and labeling, do what thou wilt.
ENHANCERS are there to enhance mineral nutes. You see, I think organics makes quality, whether it’s true or not. What is less debated is the notion that organic enhancers help make mineral nutes more available. Cation Exchange Capacity (CEC) are big words meaning “the ability for dirt to grab nutrients for later use.” Peat has nearly none, coco has some – either way, more is good. Humates, composts, organic sludge – these are midway rest stops for minerals between your bucket and your plant because they have a high CEC. Without a CEC component in peat, your nutes are pretty much only around as long as they are soluble – or, with reactive minerals, much less time. Without organic stuff, peat is only a fiber: it hasn’t any real ability to stretch the lifespan of a mineral nute until an organic component is added. Often a combination of things are used, such as guano or worm castings added to the peat – and/or some compost tea or other organic blend (or even a dash of base nute sludge, gotta love the sludge) with food irrigated in.
Next Up: Grow Store 102 – Bloom Boosters and Stimulants
Re: Peat Moss having no CEC, you may want to do more research regarding substrates. SPM actually has a higher CEC than Coco Coir. SPM is such a popular component for potting mixes because it has such a high CEC.
Mr. Duck, thanks for making a good point, space limitations in print do not always allow elaborations, leaving statements to appear dubious. My apologies for my delay, I was having technical difficulties.
Peat usually has a much higher cation exchange capacity [CEC] than soil, and is sometimes generalized as having an approximately similar CEC to coco, though more often than not coco is considered higher – an exact comparison is not really possible because both “peat” and “coco coir” refer to a wide spectrum of real-world products of varying quality. Either way, when you see that a weight-by-weight comparison of Peat to soil shows peat has up to 10x more Cation Exchange Capacity[1] you are going to wonder what Hydroguy was smoking!
This is a quote by Paul Fisher from the University of Florida explaining:
“Anyone who has picked up a pot containing field soil knows that it weighs much more than a pot containing a peat-lite medium. Peat, bark, perlite, expanded vermiculite or any other material used to produce container media typically have a very low bulk density compared to soil. In other words, you can get a lot more soil into a pot than you can a peat-lite medium.”[1]
So it has been discovered that soilless potting mixes have roughly 40-50% the CEC of soil if measured on a volume basis[1], and incidentally that is “nearly none” in the eyes of this author. If I fed my plants with 40-50% of the nutrients profiled in my back yard I would also call that “nearly none” – this is the basis of my wording.
But let’s get back to the Peat vs Coco Cation Exchange Capacities. Peat is often considered “high CEC” and Coco is considered “very high” – these terms are less than helpful, and no doubt a result of the already mentioned variations due to climate and, for peat, plant source.
Coco has a CEC somewhere in the zone of 31.7 to 95.4 cmolc kg−1 [2][3] where peat can range anywhere from between 23-200 depending on origin[4] yet studies also show that the higher-CEC peats do not really perform better due to the pesky volume issue mentioned above, and the lower CEC woody peat shows higher CEC by volume. Other sources generalize “sphagnum peat” as having a CEC around 110-130.[5]
To make matters worse, “peat” is often discussed without specification of which type of peat, and there are sources of “peat” that are indeed very high in CEC[6], however the source most often used as a medium in indoor gardening is less decomposed resulting in a lower CEC.
As far as CEC being the reason for the popularity of peat in potting mixes, that is speculation and I would personally speculate that cost and availability are the primary reasons, coupled by what other authors call “aggressive marketing campaigns by companies such as Scotts.[7]”
Another source feels the same way, or at least does not indicate CEC is calculated into the use of Sphagnum peat moss. “Sphagnum peat moss is the most commonly used soil-less medium because of its wide availability and relatively low cost. Peat moss is a very stable organic material that holds a great deal of water and air and does not decompose quickly.”[8]
But there may also be something more to the difference of CEC in peat versus regular soil composed of minerals and humus – and perhaps it’s a quality of CEC we don’t quite understand that gives humus and readily-decomposable organic material a more efficient form of CEC.
Michigan State University studied the buffering and CEC of various soilless growth mediums with a range between 5-76 meq/litre, pH balanced to 6 with lime, including peat. They concluded that, “CEC from peat has little or no effect on either pH management or calcium and magnesium management in container grown crops.”[1] Fisher summarizes further that, “In contrast to field soils, CEC of soilless media has little effect on resisting change in pH or in supplying calcium or magnesium to a crop.”[1]
Perhaps in time studies will shed some light on the matter, but for now it is relatively safe to conclude that adding an organic sludge, enhancer, or compost tea will more than likely improve your substrate’s CEC if you are using the pale-colored sphagnum peat-lite mixes.
*references available on my site