Silica is silicon dioxide, the compound in quartz sand and glass, and in the glassy deposits plants form in their tissues. In growing slang, "silica" means any silicon supplement, most often potassium silicate, sometimes stabilised silicic acid or silica-rich amendments such as diatomaceous earth, rice hulls or basalt dust.
In practice
Liquid silicate supplements go into plain water first, before other nutrients, then the pH is adjusted, because they are strongly alkaline and can gel or precipitate in a concentrated feed. Solid silica amendments release silicon slowly in soil. Cannabis does take up and deposit silicon, as Guerriero and colleagues showed, and growers report stiffer stems, though controlled cannabis yield data are limited.
Don't confuse with
- Silicon: the element itself.
- Silica gel: a drying desiccant in packets, not a plant supplement.
- Diatomaceous earth for pests: used as a physical insecticide, though it also contains silica.
Silicon (Si) is a beneficial element, not strictly essential, that plants absorb as silicic acid and deposit in cell walls, stiffening tissue and aiding stress tolerance.Potassium silicate is a strongly alkaline liquid or powder used to add silicon (and some potassium) to feeds; it goes into the water first, before other nutrients.Stabilisation is breeding a seed line over several generations, with selection each time, until it reliably reproduces the chosen traits from seed.The protective outer layer of a seed; in cannabis it is fused to the fruit wall and forms the hard shell that cracks open at germination.pH measures how acidic or alkaline a solution is on a 0–14 scale; in growing it controls nutrient uptake, with soil best near 6.0–7.0 and hydro 5.5–6.5.A beneficial element is one that improves growth or stress tolerance in some plants without being strictly essential, such as silicon, sodium, cobalt and selenium.
