A mycorrhiza is a mutualistic association between a fungus and a plant root. Cannabis forms arbuscular mycorrhizae (AM), in which fungi of the Glomeromycota grow inside root cortex cells and spread fine hyphae far into the soil. The hyphae explore a much larger volume than roots alone, improving uptake of phosphorus and other immobile nutrients and water, in return for carbon from the plant.
In practice
Growers add mycorrhizal inoculants at planting or transplant, dusting powder or granules where roots will contact them. Benefits are clearest in low-phosphorus soils and living-soil systems. High phosphorus fertilisation suppresses colonisation, so in heavily fed hydro or coco the fungi have little to offer and often fail to establish. Many products contain few viable propagules; quality varies.
Evidence: established for many crops; for cannabis, studies are limited and results mixed.being reviewed
Don't confuse with
- Trichoderma: a beneficial root-zone fungus, but not mycorrhizal.
- Mycelium (mushrooms): fungal threads in general; not all form symbioses with plants.
An immobile nutrient stays where it is first deposited, so its deficiency shows on young leaves and growing tips first: Ca, S, Fe, Mn, B, Cu.Transplanting moves a plant and its root ball into a new container or the ground; done gently it causes little shock, but GenetixBay advises against it for autoflowers.Coco coir is a growing medium made from processed coconut husk, prized for holding water and air at once; it binds calcium and magnesium unless buffered.Living soil is an organic growing medium managed to sustain an active soil food web, so microbes and invertebrates release nutrients and the soil is reused across cycles.The root zone is the volume of medium or solution where a plant's roots live, including its water, air, temperature, pH, EC and microbes.No-till growing reuses living soil from cycle to cycle without turning or replacing it, cutting out the old root ball and replenishing with top-dressed amendments.Phosphorus (P) is a mobile macronutrient used in energy transfer (ATP), DNA and cell membranes; cannabis needs moderate amounts and gains nothing from excess.Compost tea is a liquid made by steeping compost or worm castings in water, often aerated with food sources, to extract and multiply microbes for the root zone.
