It's tradition to ring in the New Year with a drink, and your plants are no different. But for many newccomers to cannabis growing, knowing exactly how much and how often to water cannabis plants can be a bit of a challenge. Seedsman starts 2026 by helping you eliminate the guesswork. If you've ever hovered over your grow tent like an anxious parent, wondering whether your plants are genuinely thirsty or just being dramatic, you've come to the right place.
The answer to the question of how often to water cannabis plants isn't a simple schedule. It's more of a fine balancing act between your medium, your pot type, your environment, and the stage of growth your plants are in. As we're at the beginning of January, we're going to focus how often to water cannabis plants indoors - with a comprehensive outdoor watering guide coming your way later in the year. Indoor growing should, in theory, give you total control. But indoor setups usually have their own quirks - just look back at our recent guide to how to grow cannabis indoors in cold weather to see exactly why.
Cold winters slow evaporation dramatically, while older houses with high humidity can keep pots wet for far longer than expected. Central heating cycles create temperature swings that affect how quickly your medium dries. Even the size of your pots changes how often you'll need to water. All of this means than learning how often to water cannabis plants indoors is less about memorising numbers and more about watching how your plants behave in your specific space. Let's walk through your plant's watering needs, step by step and stage by stage.
How Often To Water Cannabis Seedlings Indoors
The seedling stage is the stage where most new growers go wrong. Seedlings look delicate, so inexperienced growers often want to try and "help" them along with too much water. In reality, how much to water cannabis seedlings is all about restraint. It's no different from a baby - sure, they need milk, but they can only hold so much before they throw up all over your lap - and at that point, it's literally on you. The root system of a cannabis seedling is tiny, and simply cannot process large volumes of water. A small amount - just enough to moisten the top layer of the medium - is all they need. This usually works out to watering every one to three days, depending on how warm and well-ventilated your grow space is.
The goal is to keep the medium lightly moistened, never saturated. A spray bottle or small syringe can work beautifully here, allowing you to water around the seedling rather than directly onto the stem. High humidity (around 60-70%) helps seedlings stay hydrated without relying entirely on root uptake, which is still developing. Overwatering your seedlings leads to damping-off, a common fungal issue that can wipe out young plants overnight, so gentle, measured watering are absolutely essential.
Quick insight: If the top layer stays wet for more than 48 hours, you're watering your seedlings too often.
How Often To Water Cannabis in the Vegetative Stage
Once your plants move into veg, everything changes. Roots expand, leaves multiply, and your plant is looking to pack on mass, so that thirst increases dramatically. This is where growers really start to ask how often to water cannabis plants indoors, because the pace picks up quickly. In soil, most plants will need watering at least every two to four days, while coco growers will find themselves watering daily - sometimes more. This is because coco allows water to drain away quickly without the risk of overwatering.
The key is to water thoroughly when you do water. Indoor plants benefit from full saturation followed by a period of drying, which encourages strong root development. You're aiming for a healthy wet-dry cycle, not constant moisture. When the pot feels noticeably lighter and the top few centimetres of medium are dry, it's time to water again. Leaves should look perky at lights-on; if you notice they're drooping first thing in the morning , that's usally a sign of overwatering rather than thirst.
Quick insight: A vegging plant that needs watering more than once a day is almost always in too small a pot. Time to start transplanting safely.
How Often To Water Cannabis During Flowering
Flowering cannabis plants are especially thirsty creatures, especially when you're growing them under modern LED lighting, which increases leaf-surface temperature and drives transpiration. In soil, most indoor plants will need watering at least every two or three days, while plants grown in coco will need daily watering, or sometimes even twice-daily watering for larger specimens. This is where understanding how to water cannabis in coco becomes especially crucial, because coco behaves more like a hydroponic medium than soil. It holds air exceptionally well, even when saturated, so it dries quickly and must never be allowed to fully dry out.
As buds begin to develop, your watering rhythm becomes even more important. Overly wet pots in a cool UK home can raise humidity around the canopy at night, increasing the risk of mould. In the final week or so before harvest, many growers will slightly reduce watering volume or frequency to help keep humidity down and avoid soggy conditions around desne flowers. You're not "flushing" in the old-school sense - you're simply managing moisture to protect your buds.
Quick insight: If you're growing in soil and your plants still need watering daily, your tent is probably running too hot - or too dry. Adust your temperature and RH.
How Often To Water Cannabis In Coco Coir
We've already touched on coco coir, but it deserves its own section because it changes everything about how often to water cannabis plants. Coco is fast-draining, airy, and designed to be watered frequently. Most coco growers water at least once a day in veg and often twice a day in flower. Smaller pots may even require a few small waterings per day under strong lights. Because coco contains no nutrients of its own, every watering must include a nutrient solution. Runoff is essential to prevent salt buildup, and the medium should never be allowed to dry out completely.
Coco is incredibly forgiving when kept moist - but if not, it punishes neglect quickly. Once you understand its rhythm, though, coco offers explosive plant growth and excellent control.
Quick insight: If coco ever feels dry to the touch, your watering frequency is already too low.
How To Water Cannabis in Fabric Pots
Fabric pots offer another layer of complexity. They're brilliant for root health because they allow air to penetrate from all sides, encouraging air-pruning and preventing circling roots. But that same airflow means they dry out faster than plastic pots. If you're learning how often to water cannabis in fabric pots, expect to water more frequently - sometimes significantly more.
The trick with fabric pots is to water slowly. Fabric pots can channel water striaght down the sides if you pour too quickly, leaving the centre dry. A slow, steady pour ensures even saturation. Rotating the pots occasionally helps them dry evenly, and using saucers or plates to catch runoff will prevent your tent floor from becoming a swamp. Just don't let the pots sit in the runoff - fabric will help wick it back up, keeping the medium wetter than intended.
Quick insight: Fabric pots typically shorten the wet/dry cycle by about 20-40%, meaning you'll water noticeably more often.
Is Distilled Water Good For Cannabis?
This is a question that pops up often, and the answer depends on how you''re using it. Distilled water is good for cannabis, but only in certain situations. It's good because it's pure, free of contaminants, and ideal for seedlings, clones, or growers dealing with extremely hard tap water. However, it contains no minerals at all, which means mature plants can quickly develop calcium and magnesium deficiencies if you rely on distilled water alone.
If you plan to use distilled water long-term, you'll need to add a Cal-Mag supplement to keep your plants healthy. Coco growers in particular must be careful, as coco binds calcium and magnesium, making supplementation essential. Distilled water is a tool - not a complete solution - and it works best when used intetionally rather than by default.
Another factor to consider is how distilled water affects watering frequency. Pure water has very low buffering capacity, meaning it doesn't hold pH or minerals well. As a result, your medium can dry out slightly faster, and nutrient uptake becomes more sensitive to fluctuations. Growers often find themselves watering a bit more frequently when using distilled water exclusively, simply because the medium doesn't retain dissolved solids that help stabilise moisture and nutrient levels.
Reading Your Plants and Pots
Ultimately, mastering how often to water cannabis plants indoors comes down to observation. The finger test, the lift test, and simply watching how your leaves behave will tell you far more than any fixed schedule. Dry topsoil, a light pot, and leaves that perk up after watering are all signs you're on the right track. Heavy pots, drooping leaves at lights-on, or slow growth usually point to overwatering. One of the best pieces of advice around watering plants is this: If in doubt, wait - underwatering is corrected in minutes, but overwatering takes days to repair.
Indoor watering is a skill that becomes second nature with practice. Once you understand your medium, your pot type, and your environment, you'll stop asking how often to water plants indoors - you'll simply know, instinctively, what your plants need.
