Question: My family has been growing various crops on our land for many years; I have been considering cultivating both cannabis for consumption and hemp for extracts. I've been advised to get my water and soil analyzed, but our land has very successfully produced a multitude of crops for generations, so I know the water is good and the soil is fertile. What is the relevance of the testing? What should I be looking for?
Answer: First, it is important to understand that cannabis and hemp plants are remediator plants, also known as phytoremediators. This plant category absorbs almost everything and anything from its environment, including the air, water, and soil. Through a process called phytoremediation, these plants can clean up contaminated areas filled with solvents, pesticides, and heavy metals. In fact, hemp plants have been utilized to remediate nuclear fallout from the Chernobyl disaster.
Knowing this, the importance of both water and soil testing becomes clear.
Now, let’s address water analysis. A complete water analysis test must be performed on water destined for cannabis or hemp cultivation for a multitude of reasons. Well water from a contaminated source can cause crop test failures from heavy metals. Therefore, you must always test both soil and water for heavy metal contamination, which is especially important for land that has previously had a history of traditional farming, as industrial, agricultural, and human inputs have contributed to widespread water contamination.
Heavy metals are categorized as elements with elevated atomic weights and high densities. Cadmium, mercury, and lead are all classified as heavy metals. Other elements, for instance, iron and zinc, are essential micronutrients when present in trace amounts, but are considered toxic at elevated levels.
Besides contamination from heavy metals, cultivators should be aware of the mineral content of their source water. Hard water contains high levels of dissolved minerals, predominantly calcium and magnesium. These minerals are absorbed as water travels through deposits of soil/rocks, for example, chalk, gypsum, and limestone. All of these can cause mineral buildup in soil, which can both alter pH and interfere with nutrient uptake.
So, it is best to always get a complete water analysis performed on any potential water source destined to be utilized as agricultural irrigation, which is especially important when producing either cannabis or hemp for consumption.
Regarding soil analysis, pollutants such as pesticides, fertilizers, animal waste, and eroded sediments can render crops unfit for consumption. Soil contamination can be the cause of cannabis failing testing for heavy metals and pesticides. It is not enough to simply know that your soil is fertile for crop production; you must be certain that there is not anything detrimental in it that would transfer to the finished product and render it unfit or unsafe for consumption.
Just because you have successfully and repeatedly cultivated crops using the same water source on your same land does not necessarily make them safe for hemp or cannabis crops. Having more knowledge about the composition of your soil and water also enables you to augment any missing macro- or micronutrients, and adjust their pH as needed.
These tests will ultimately benefit both your potential cannabis and hemp crops, as well as any other crops you cultivate, improving yield, health, and quality.
Kenneth Morrow is an award-winning grower and breeder. He is the owner of Trichome Technologies, a research and development company. He is also a consultant and author of the book "Marijuana Horticulture Fundamentals" and a founding advisory board member of Cannabis Business Times, where he has been a columnist since 2015. Find him on Instagram @trichometechnologies or reach him via email at: [email protected].
