Use of Organic vs Conventional fertilizers for Marijuana
29 March 2022
Organic vs. Conventional
It is important to briefly address the issue of organic versus conventional fertility programs. This question really comes down to personal beliefs and the market in which you wish to work. Organic products generally have lower concentrations of available nutrition, but over time can break down to provide the nutrients needed. Conventional products are cheaper per unit of nutrition, but if used in excess can limit soil microbial activity and structure. Both options, when done right, can produce a quality product.
On a side note, production ag is learning that the principles of soil stewardship — which form the basis of the organic movement — really can benefit the crop. This has led to the use of conventional fertilizers along with organic methods, such as composting and no-till, to produce great results. From a pure yield and quality standpoint, conventional versus organic does not matter. The chief factor is that the fertility program meets the needs of the plants throughout the growing cycle.
Designing and implementing a quality fertilizer program comes down to several key considerations:
– Growing media: From a nutrient standpoint, growing in soil or a soilless media are very different. Soils are comprised of minerals that can inherently provide some of the nutrients needed. Soil also acts as a buffer that holds onto nutrients and mediates pH. Soil testing should be conducted to know what elements are available in the soil and what needs to be added. Soil testing will also let growers know if their soils have other issues such as high salinity or poor organic matter content.
Growing in soilless medias or hydroponics requires continuous availability of all nutrients and closer monitoring to ensure that nutrients are at the proper levels. This is important at not just an electrical conductivity (EC) or total parts-per-million (PPM) level, but also at the individual nutrient level if long-term water recirculation is being used. At certain growth stages, plants can use up all of one nutrient in the solution. This may not be reflected in a major jump in EC or total PPM if the nutrient is a minor component, such as zinc or boron, but can lead to severe deficiency symptoms. Furthermore, due to the inert nature of soilless culture, swings in pH and nutrient depletion can be fast; thus, close monitoring is essential.
– Crop requirements: Plants use different nutrients at different rates. This is where fertilizer formulation comes into play. A good formulation will have a balance between all the nutrients contained in the product, so that total PPM or EC is indicative of the actual total nutrient availability. This, however, is very difficult to achieve in practice because the plant’s nutrient requirements change throughout the growth cycle. Formulations for rooting, vegetation and bloom exist in the marketplace to help meet the specific nutrient needs of the plants at these critical steps in the growing process.
– Timing: Timing of application is essential to provide the plant with the nutrition it needs when it needs it. There are critical points in the plant’s development when the yield of the crop will not be acceptable if nutrition is lacking. For example, during early bud development, if complete nutrition is not provided, the bud will not differentiate as many reproductive structures, thus limiting the crop’s yield. This is true from cherries to broccoli to marijuana.
– Product support: It is inevitable that you will encounter an issue while using a product when it is essential to have a knowledgeable person available via phone or email to solve your issue quickly.
– Price: The price of a product does not indicate its quality or value. These come from the formulation and inputs used to make the product. When selecting a fertilizer, make sure the price of the program is within your budget, but do not assume that a high price necessarily indicates a good product. Conversely, low price also does not mean poor quality. The value of the product is in the formulation expertise, and the cost is in the container and shipping.
– Recordkeeping: It is essential to keep records of rates, timings and products used to be able to replicate the practice in the future or adjust it to make improvements. This is true for other production factors as well. Good growers have an idea of what went wrong or right. Great growers know exactly what was different and can fix or replicate it the next time around.
Following these guidelines will help to make your fertility program shine. Specific products or rates were not suggested in this article because each growing condition is very different. An outdoor, in-ground growing operation in Humboldt County, California will have very different requirements than a hydroponic greenhouse in Denver, Colorado. These guidelines will help develop a nutrient program that can be perfected for specific growing conditions. Learning from each crop cycle and adjusting accordingly will produce a better crop and help growers learn what each component affects.
Fertility, however, is only a small part of the growing practice. Deficits in pest control practices, watering, cultivar choice, climate monitoring and control, soil salinity and water quality all need to be managed to produce a marketable crop. It is very common for nutrient deficiency symptoms to occur due to some other problem not related to the fertility program. For example, high salts in the soil can cause burnt tips and an over-saturated soil can cause yellowing of the leaves. A balanced, well-maintained production system is required for a quality crop.
The use of a fertilizer tailored for the needs of the crop is important for top production. Also, a product that meets the different requirements at each growth stages (rooting, vegetative, bloom, etc.) will provide even better results.
This is not a buyer’s guide with comparative tests, so it’s not meant to offer specific product recommendations; as stated earlier, growing conditions are unique and the products that work for one grower may not be the same as the next person. Keeping records and making improvements when needed will allow growers to maximize their yield and consistently produce a quality product.