The Invisible Input
Ask a cannabis grower about their genetics and you'll get a twenty-minute answer. Ask about their soil recipe and they'll pull out a spreadsheet. Ask about their water and you'll usually get a blank stare.
Water is the single largest input by volume on any cannabis farm. A mature plant in full flower can drink two or more gallons per day. Over the course of a growing season, we're pushing thousands of gallons through our beds. Every mineral, every contaminant, every pH point in that water interacts with our soil biology, our nutrient cycling, and ultimately our flower quality. And yet most growers treat water as an afterthought — something that comes out of a tap or a hose and goes into the pot.
In a living soil system, water quality isn't just important. It's foundational. The biology you've spent years building can be disrupted by what's dissolved in the water you use to irrigate it.
What's in Your Water
Municipal water — the stuff that comes out of city taps — is treated with chlorine or chloramine to kill bacteria. That's great for public health. It's terrible for living soil. Those same antimicrobial compounds that make tap water safe to drink also kill the beneficial bacteria and fungi in your soil. Every time you water with untreated municipal water, you're sterilizing the top layer of your growing medium. Over time, this degrades the biological networks that make living soil work.
Well water avoids the chlorine problem but introduces others. Depending on your geography, well water can be high in dissolved minerals — calcium, magnesium, iron, manganese — that affect soil chemistry and plant nutrition. In some regions, well water contains heavy metals like arsenic or lead at levels that accumulate in plant tissue over time. In agricultural areas, groundwater may carry residual nitrates from fertilizer runoff.
The point isn't that all water is bad. It's that water is a variable, and if you don't know what's in yours, you're growing blind.
The Maine Difference
One of the less-discussed advantages of growing in Maine is the water quality. Our well water is exceptional — naturally soft, low in dissolved solids, with a slightly acidic pH that's nearly perfect for cannabis without adjustment.
Maine sits on ancient granite bedrock, and the groundwater that filters through it picks up minimal mineral content. Our total dissolved solids (TDS) readings typically come in under 50 parts per million — compared to 300-500 ppm that's common in the western states. This means we're starting with essentially a blank canvas every time we irrigate. The water delivers moisture without adding mineral baggage that would throw off our soil chemistry.
The low TDS also means we don't need to run reverse osmosis or other filtration systems that are standard equipment in most indoor grows. Less equipment, less energy, less waste. The water comes out of the ground ready to use.
Good water is invisible. Bad water is everywhere — in every leaf tip burn, every lockout, every mysterious deficiency that doesn't match the soil test.
pH and Soil Biology
In synthetic growing, pH management is a constant battle. Growers adjust their input water to a precise pH range — typically 5.8-6.2 for hydro, 6.0-6.5 for soil — and monitor runoff to make sure it's staying in range. Drift in either direction causes nutrient lockout, and the whole system depends on the grower maintaining that narrow window manually.
Living soil handles pH differently. A biologically active soil is self-buffering — the humic and fulvic acids produced by decomposing organic matter, combined with the metabolic activity of soil organisms, create a natural buffering system that maintains pH stability without grower intervention. The soil adjusts to the water, not the other way around.
This doesn't mean water pH doesn't matter at all. Extremely acidic or alkaline water can overwhelm the soil's buffering capacity, especially in younger beds that haven't accumulated much organic matter. But in a mature living soil system, the pH of your input water is far less critical than in synthetic growing because the biology is doing the regulation work for you.
Our Maine well water comes out at around 6.2-6.4 — right in the sweet spot for soil applications. We don't pH adjust. We don't add acids or bases. The water goes straight from the well to the beds, and the soil takes care of the rest.
Chlorine, Chloramine, and What to Do About Them
For growers who don't have the luxury of clean well water, dealing with municipal water treatment chemicals is a real challenge.
Chlorine is the easier one to manage. It's volatile, meaning it will off-gas naturally if you leave your water sitting in an open container for 24 hours. Aerating the water with an air pump speeds this up significantly. Most growers who use city water can eliminate chlorine with a simple holding tank and pump setup.
Chloramine is the harder problem. Many municipalities have switched from chlorine to chloramine because it's more stable in the distribution system — which is exactly what makes it difficult for growers. Chloramine doesn't off-gas. You can leave it sitting for a week and the levels won't change. Removing it requires either a carbon filter rated specifically for chloramine, or treatment with ascorbic acid (vitamin C), which neutralizes the compound on contact.
If you're growing in living soil and using municipal water, addressing chlorine or chloramine isn't optional. It's not about plant health — the plants themselves tolerate these compounds fine. It's about soil health. Every irrigation event with treated water is a setback for the microbial community you're trying to build.
Irrigation Philosophy
Beyond quality, the how and when of watering matters enormously in living soil systems.
We irrigate infrequently and deeply rather than frequently and lightly. This encourages roots to grow down into the soil profile, chasing moisture rather than waiting for it to arrive at the surface. Deep-rooted plants are more resilient, more nutrient-efficient, and better connected to the mycorrhizal networks that live in the lower soil horizons.
We also avoid overhead watering during flower. Wet foliage in Maine's humid late-summer climate is an invitation for botrytis and powdery mildew. Our irrigation goes to the soil surface through drip lines or hand watering, keeping the canopy dry while the root zone stays consistently moist.
The goal isn't to maintain perfectly even moisture at all times. Some dry-back between irrigations is healthy — it promotes root growth, improves oxygen availability in the root zone, and can actually stimulate terpene production as a mild stress response. The art is finding the rhythm that keeps the soil biology active without drowning it, keeps the plants healthy without coddling them, and lets the natural systems do most of the regulation work.
Clean water, applied thoughtfully, into living soil. It's not complicated. But it's the foundation that everything else is built on.