What are the technical differences between soil, coco, and hydro?
The core difference is how much buffer sits between you and the roots. Soil has organic matter, microbiota, and high cation exchange capacity (CEC): it absorbs pH mistakes and overfeeding, but it also slows the plant's response. Hydro is the opposite extreme — roots in solution, total control, maximum speed, but any deviation hits in hours. Coco lives in the middle: it drains fast, responds quicker than soil, but it sequesters Ca²⁺ and Mg²⁺ at its exchange sites if you don't pre-buffer it before transplant.
What do studies say about yield across each medium?
In coco, what matters most isn't the brand but the container capacity (CC): a more porous, well-draining coir (low CC) produced higher dry flower weight and greater THC concentration than a wetter coir (Caplan, Dixon & Zheng 2017), though it required more fertigations. In soil, Burgel et al. (2020) found greater plant height and root density in peat-based substrates, but cannabinoid profile was primarily determined by genetics. For hydro, direct head-to-head flower yield data is limited.
Does the medium change THC or terpene levels?
Mostly, no — not directly. The review by Malík & Tlustoš (2025) concludes that cannabinoid concentrations are primarily genotype-driven under stable environmental and nutritional conditions: the medium modulates biomass and nutrient-use efficiency, but it doesn't determine the profile on its own. The honest takeaway: if you're chasing terpenes or cannabinoid levels, genetics and feeding management matter more than medium choice.
Why does coco always need cal-mag?
Unbuffered coir comes loaded with Na⁺ and K⁺ at its exchange sites — residue from processing. When you water, those sites release Na/K and lock up Ca²⁺ and Mg²⁺ from your nutrient solution. The result: calcium and magnesium deficiency even when your feed contains them. Best practice is to pre-buffer the coco with calcium before planting (Caplan, Dixon & Zheng 2019) and supplement cal-mag throughout the cycle.
What's the real trade-off with hydro?
Hydro gives you the greatest control over nutrition and eliminates soil-borne pests. Rockwool, the industry-standard substrate, has near-zero CEC and high air porosity, allowing maximum precision in fertigation (Nemati et al. 2021). But that same inertness means there's no buffer: a pH error, a pump failure, or an out-of-range concentration hits within hours. Coco, by contrast, is the intermediate medium with the most advantages and fewest drawbacks according to that same review.
Which medium fits which type of grower?
- Soil / living soil: ideal for beginners, low upfront cost, greater tolerance for watering and feeding mistakes. Requires managing soil fungi and fungus gnats.
- Coco: for growers who want more speed than soil without the full demands of hydro. Non-negotiable: pre-buffer with Ca/Mg, water frequently, monitor EC and pH.
- Hydro (rockwool / NFT / DWC): maximum control and speed, minimum margin for error. Requires monitoring experience and zero tolerance for improvisation. Not ideal as a first system.
