One hotly contested topic among Cannabis gardeners is whether to use chemical-based or organic nutrients. While it is fine to disagree, there are benefits to both, and ignoring the camp you don’t agree with has been the cause of a lot of ignorance in the world.
Nitrogen (N), phosphorus (P), potassium (K) and other nutrients are needed by plants for healthy growth. These are elements, and as such, there is no difference between the nitrogen from an organic nutrient or a chemical version. Elemental nitrogen is the exact same thing, regardless of the source.
What garden plants most often use to allow them to take up nitrogen is a form known as nitrate (NO3), which is a nitrogen atom connected with three oxygen (O) atoms. NO3 is an easy form from which the plants can separate nitrogen from oxygen, and therefore makes for a good source of nitrogen (woody plants like trees can also use ammonium).
Plant material that has fallen to the ground and animal waste material are two sources of nitrogen that naturally occur in untended wilderness. To emulate this, organic nutrients tend to be made from naturally occurring materials, with minimal processing. One advantage to this is that the materials can often be collected cheaply – e.g., leaves, lawn clippings, livestock manure, etc. Compost (3-1-2) is very similar to what happens in nature when leaves fall, and assorted other plant material winds up on the ground when nobody is around to rake it up. As these things decompose (or compost), bacteria and fungi convert them into ammonia (NH3), and ammonium (NH4). This takes time, as the bacteria only process the ammonia as they get to it.
I like to compare organic nutrients to eating oatmeal for breakfast – they tend to be bulky and release their nutrients over a long period of time. Some forms of organic fertilizers can continue to release nutrients for more than one season, improving the general long-term health of the soil. Because the percentage of nutrient to total mass tends to be lower, the N-P-K values of organic nutrients tend to be lower than that of chemical-based solutions. Because they are closer to a natural state, the N-P-K values of organic products also tend to be less exact than chemical-based fertilizers, which can be made to exact recipes. With the exception of high-ammonia ‘hot’ manures, organic nutrients tend to be less prone to overfeeding. Compost, worm castings and fish excrement can be used in almost unlimited quantities without causing ‘nute burn’. Since organic nutrients tend to be less processed, they also tend to be more prone to clogging hydroponic systems that rely on sprayers and pumps.
However, there is more than one way to make NH3: it can also be manufactured chemically from nitrogen gas (N2) by applying heat, pressure and an iron catalyst. Ammonium sulfate, (NH4)2SO4, and ammonium nitrate, NH4NO3, are other manufactured forms of nitrogen that allow for later parts of the process to be skipped over. Any of these enable a shortcut in the process, and make the nitrogen available faster than with the natural method.
Chemical nutrients are more like having an energy drink for breakfast – they release their nutrients quickly, and then need more to avoid a ‘crash’. Since chemical nutrients are shortcuts to the natural process, they can allow for a greater level of control as to how much, and when, the nitrogen becomes available to the plants. This can allow for a higher nutrient level and resulting increase in performance than is possible with organic nutrients.
With this level of control comes responsibility, however, as introducing an overabundance becomes a much more likely temptation, which can result in ‘nute burn’, overloading and damaging natural systems with the runoff. Adding a chemical version of NO3, for example, allows for the entire nitrate creation process to be skipped, and immediately supplies nitrogen to the plants; however, it is also very water-soluble and what isn’t taken up by the plant will quickly wash downstream (unless recirculated).
Overdosing plants with chemicals can imbalance a natural system to where it becomes inhospitable to the beneficial bacteria and fungi normally responsible for the process. Because chemical fertilizers are shortcuts, using them to treat nutrient deficiencies tends to give faster results than organic solutions, which is better suited for long-term release. Depending upon the exact chemical used, there may also be leftover residue after the ammonia or nitrate is used, which can build up in the system over time. This is where the practice of watering heavily without nutrients for a time (flushing) comes from, to help wash away any leftover chemical residue build-up.
Regardless of the source, if the NH3 is exposed to acidic conditions (pH less than seven) it picks up another hydrogen (H) atom and converts to ammonium (NH4). This is partially why pH can have an effect on plant growth; if the pH is too high, this conversion is inhibited. Beneficial bacteria then convert the ammonium to NO3, which can then be used by the garden plants.
Phosphorus can be obtained naturally from organic composts, rock phosphate or bone meal, or it can come from chemicals such as ammoniated superphosphate (5-50-0), or ammonium phosphate (18-46-0). Overuse of phosphorus is one of the sources of environmental pollution. Potassium can be from organic sources like compost (3-1-2), kelp (1-0-4), or from a chemical such as (13-0-44).
The differences between chemical and organic nutrition are not as absolute as they are often portrayed – they both supply the same elements to the plants. The primary differences are in how many shortcuts are taken, and what remains afterward. Although purists on both sides may strongly disagree, I believe there is little reason not to make use of the benefits of both, in moderation. Plants awaiting organic nutrients to become available may benefit from a little chemical boost to tide them over, and long-lasting organic materials can help create a buffer for fast-acting chemical nutrient gardens.
Sometimes a big, hearty, high-fiber breakfast is what a person needs to start the day; sometimes you just need a good strong cup of coffee to get your eyes to open. As always, understanding why you are adding something to your garden, and how it works, goes a long way toward picking what’s right for you.
Peace, love and puka shells,