Jeff Lowenfels is a writer, national lecturer, and a fellow, hall of fame member, and former president of the Garden Writers of America. He is the author of two popular books on soil and cultivation, “Teaming with Nutrients: The Organic Gardener’s Guide to Optimizing Plant Nutrition” and “Teaming with Fungi: The Organic Grower’s Guide to Mycorrhizae.” He is also the co-author of the award-winning “Teaming with Microbes: The Organic Gardener’s Guide to the Soil Food Web.”
Lowenfels has a great deal to contribute to the dialog on how plants eat and what we should feed them. It is a complicated topic, but an important one for gardeners to understand. He explains, “There are 18 nutrients that a plant takes in, and that’s it.” To process those 18 nutrients plants have very complex machineries, which Jeff describes in detail in his book, “Teaming with Nutrients.” He is amazed by the beauty and intricacy and enthuses, “This is the most gorgeous process you could possibly imagine.” However, it is not just a thing of wonder, but an important process to grasp. If growers understand how plants eat, it becomes much simpler to feed and care for them.
What a plant absorbs is dictated by its cell membranes and only a particular kind of molecule can pass through each cell membrane. There are 18 different kinds of molecules that pass through the protein channel in the membrane and then travel to the cell to be processed. There the cell uses those nutrients to produce the molecules that make up the plant, from the terpenes to the stalk. A cannabis plant might have 27 billion cells with each cell containing 1,000 different kinds of enzyme and 10,000 of each kind of enzyme, together they make up the cytoplasm package.
Unsurprisingly, the plant’s make-up and this process are intrinsically linked to the soil food web and mycorrhizal fungi which Jeff has also written much about. He is passionate about the symbiotic relationship between the plant and the earth. He points out, “Plants prove themselves to be a most amazing thing, and for a cannabis grower not to understand how [they] operate, is a shame, frankly.” Once growers do understand this relationship and how plants move nutrients around, it begins to answer questions of care. For example, timing: plants only require a small amount of boron to form pollen tubes, and this formation only happens at a certain point in the plant’s life. If that boron window is missed, Jeff explains, “You’re not going to get a good set of plants.”
Interestingly, the plant-nutrient process also answers the ultimate question of the cannabis grower: to flush or not to flush. For Jeff it is simple and scientific, “Once you understand those membranes and those … proteins … you begin to understand that flushing is a complete waste of time.”
Another polarizing issue is whether to grow cannabis hydroponically or in soil. Lowenfels does believe it is possible to do hydroponics organically, but that soil is by far the better choice. He states, “If you know how [the soil food web] operates, you can feed the soil so that it’s feeding the plant at all times.” Jeff recommends beginning with the very best soil available, one with the highest microbiology, and adding good compost to it. The soil should be treated with compost teas to feed the microbes, have mycorrhizal fungi added to the plant root area, and be well-mulched. Jeff explains, “I mulch my soils because there are not bare soils in the soil food web. There’s always a mulch layer, which is the king in feeding in your plants.” He prefers either a living mulch in the form of a cover crop or a green mulch combined with seed-free straw. The straw is particularly beneficial as it is covered with paramecium which are partial to protozoa.
Imitate Mother Nature: reuse, recycle
Not everyone is blessed with the temperate environment of northern California, so this is particularly useful advice for those growing inside using containers. Lowenfels encourages all growers, but especially those growing inside, to be wise and efficient. Soil should be composted and reused, even on other plants, never discarded. “We shouldn’t have that luxury,” Jeff states. To help identify the quality of the soil, Jeff suggests testing it. First, test the fungal bacterial balance; second, test the microbial biomass using a MicroBiometer. The biomass is key. If the results read 900 on the scale, then there is no need to feed the plants.
Underlining the need for an organic and regenerative approach to agriculture, Jeff does not recommend chemical fertilizers. He explains, “there’s no question it works, but eventually … you throw things out of whack. You either lose your soil structure, or … your microbiology balance and all of a sudden, something happens … and there’s nothing to correct it, because you’re the soil food web.”
Lowenfels is no fan of pesticides either, preferring the natural methods that can be used to deal with pests instead. Trapping using companion planting is a common and effective solution. Jeff describes a friend who grows a small grove of bananas among his cannabis plants to attract pests away. Pests can also be controlled using biological methods, such as predatory nematodes. These biologicals are now are being tested and developed specifically for the cannabis grower, which means they are more widely available than ever before and cheap to purchase.
Years of research, writing, and growing have shown Jeff that this carefully constructed, natural relationship between plants and the earth simply needs our stewardship not our intervention. It isn’t possible to compete with thousands of years of evolution, and why would we want to? He is convinced that cannabis is America’s next tomato. Once believed to be poisonous and universally mistrusted, tomatoes are now grown everywhere and consumed by everyone. Jeff envisages the same happy ending for cannabis, with it grown not just for health, but as an herb for cooking and as structure for landscaping. He enthuses, “It is a beautiful plant with some spectacular colors and shapes.”