In the vegetative stage, cannabis wants steady moisture and a feed that leans on nitrogen. Water when the top inch or two of the medium feels dry and the pot feels light. Feed at an EC around 1.0 to 1.6 (roughly 500 to 800 ppm on the 500 scale) with pH at 6.0 to 6.8 in soil or 5.6 to 6.2 in coco and hydro. Early veg sits at the low end of those ranges. By the last week of veg, most plants drink daily and eat at full strength.
cannabis veg stage nutrient requirements
What changes during veg
Once seedlings or clones have a few real leaves, the plant stops living off stored energy and starts building structure. Roots expand fast, stems thicken, and leaf area doubles in a hurry. That growth is the reason water use climbs week by week. A plant that drank a cup every three days in week one may pull a gallon a day by week five.
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Nutrient demand follows the same curve. Nitrogen drives leafy growth, phosphorus matters less right now, and potassium supports stem strength and water movement. A veg feed in the 3-1-2 neighborhood works for most setups.
what temperature for cannabis veg stage
How often to water in veg
Forget the calendar. Pick up the pot. A planted container feels heavy when it is saturated and noticeably light when the medium has dried back. I check weight, then poke a finger an inch or two into the top layer. Wet there? Wait a day and check again.
Sizing the dryback
In soil, let the top inch or two dry between waterings. In coco, aim for a smaller dryback, maybe 20 to 30 percent of the medium moisture, since coco holds water differently and roots like the air that comes with more frequent cycles. In hydro, watch the water level and top off with plain water between reservoir changes.
How much to pour
Water slowly until you see runoff, then stop. A common target is 10 to 20 percent of what you poured coming out the bottom. That runoff flushes salt buildup before it can burn tips. Skip the runoff and you will see it in the leaf margins within a couple of weeks.
Pot size sets the volume. A 1-gallon pot might take a quart. A 5-gallon pot might take a gallon and a half. Pour in stages, let it soak, then finish.
Water quality and temperature
Cold tap water shocks roots. Let it come to room temperature, roughly 65 to 72°F, before it touches the medium. If your tap water runs hard or smells like chlorine, let it sit in an open container overnight or run it through a carbon filter. Chloramine will not off-gas, so filter it or use RO.
If you use RO or distilled water, add a calcium and magnesium supplement. Coco needs one too, because it holds onto calcium and magnesium and hands back potassium and sodium.
Feeding strength in veg
Start light. Seedlings and fresh clones can burn on full-strength veg nutrients, so begin at a quarter to half strength and move up as the plant adds leaves. A reasonable ramp: EC 0.6 to 1.0 in weeks one and two, 1.0 to 1.3 mid veg, 1.3 to 1.6 in late veg. Push into the high end only if the plant is a heavy feeder and the leaves stay flat and green.
pH and EC targets by medium
- Soil: pH 6.0 to 6.8, EC 1.0 to 1.6
- Coco: pH 5.8 to 6.2, EC 1.2 to 1.8 with CalMag included
- Hydro (DWC, ebb and flow, NFT): pH 5.5 to 6.2, EC 1.0 to 1.6
Mix nutrients in order, stir between each bottle, and check pH last. Adjusting pH before everything is in the water means you will adjust twice.
Reading the plant
Leaves tell you which way to correct before the damage gets expensive.
- Droopy leaves with a heavy pot: overwatering and low root oxygen. Let it dry back further.
- Droopy leaves with a light pot and dry medium: underwatering. Water to runoff and watch recovery time.
- Pale lower leaves, slow growth: nitrogen is short. Raise feed strength or switch to a veg formula.
- Dark, glossy, clawing leaves: too much nitrogen. Dilute the next feed.
- Brown spots and curled new growth in coco: calcium or magnesium shortage. Add CalMag.
- Crisp brown leaf tips: salt buildup. Flush at low EC and resume feeding.
A simple veg week
- Check pot weight daily and water when the medium has dried back.
- Feed at the EC that matches the plant's size, and water to 10 to 20 percent runoff.
- Check runoff pH and EC once a week. Rising EC means salt is accumulating.
- Keep temperature 70 to 85°F and humidity 55 to 70 percent.
- Log what you poured and when. Patterns show up fast in a written record.
Veg is the easy part compared to flower, but it sets the frame for everything that comes after. Get the watering rhythm and feed strength right now, and the plant enters flower with strong roots and no nutrient debt.