Short answer
Feed soil plants less often than coco or hydro plants. A workable baseline: plain pH-adjusted water for the first week or two after transplant, quarter-strength veg feed around week 3, half to full strength through late veg, then a lower-nitrogen bloom feed from flower week 1. Top-dress dry organic amendments every 2 to 3 weeks, or use bottled nutrients every other watering. Keep water pH around 6.3 to 6.8 and check runoff now and then. Autoflowers and fresh, compost-rich soil usually need less.
Why a soil schedule is different
Soil is not just a sponge. It holds nutrients on cation exchange sites, buffers pH, and supports microbes that break down organic matter. That means the medium feeds the plant between your inputs. I look at soil grows as a slower system. You are feeding the soil and the plant at the same time. Salt-based nutrients work fast, but they build up if you feed every watering. Organic amendments break down over weeks, so they are easy to overdo at the start and hard to fix later. Pick one style and stay close to the label. Mixing heavy salt feeds with heavy dry amendments is a good way to burn tips.
Cannabis Nutrient PPM Schedule
Week-by-week soil feeding schedule
Use this as a starting point, not a rulebook. Strain, pot size, light intensity, water quality, and soil mix all change the dose. Watch the plant and the runoff.
cannabis nutrients schedule for beginners
Week 1 to 2: seedling or fresh transplant
No feed if your soil has compost, worm castings, or a charged mix. Water small amounts around the root zone. Keep the surface from staying soggy. If you see pale cotyledons or slow growth, a quarter-strength root or veg feed is enough. Most problems at this stage come from too much water, not too little food.
cannabis nutrient ppm schedule
Week 3 to 4: early veg
Start light. Use a quarter-strength veg feed every other watering, or top-dress a balanced organic fertilizer at half the label rate. Add a microbe product if you have one. Water to a little runoff and let the pot dry back. Roots need air as much as water.
Week 5 to 6: late veg
Move to half or full strength veg feed, depending on how the plant looks. Healthy new growth should be green, not dark and waxy. If leaf tips claw down, back off nitrogen. If lower leaves fade, feed a little stronger. This is also a good time to check runoff EC or ppm if you use bottled nutrients. High runoff numbers mean salt is collecting.
Flower week 1 to 3: transition and stretch
Switch to a bloom ratio, but do not cut nitrogen to zero right away. The stretch uses food and calcium. Feed at half strength for the first bloom week, then move to a normal bloom dose. Keep pH in range. A calcium and magnesium supplement helps if you use reverse osmosis water or see spotted leaves.
Flower week 4 to 6: bulk
This is the heaviest feeding window for most photoperiod plants. Use a bloom feed with more phosphorus and potassium, and follow the label. Feed, water, feed is a safer pattern in soil than feeding every time. Top-dress dry amendments every 2 to 3 weeks. Watch for burnt tips and crispy edges. Those are signs to mix the next feed weaker.
Flower week 7 and beyond: taper
Cut nitrogen and reduce overall feed as the plant slows down. Plain water every other watering is fine. Organic soil does not need a hard flush. If you used bottled salts, a mild plain-water finish for the last week or two can help. Do not starve the plant while buds are still swelling.
How much to feed
Label rates are a guide, not a target. Start at one quarter strength for young plants and one half strength for established plants. Work up. If you measure EC, keep soil feeds modest. Many soil growers run around 0.4 to 0.8 EC in early veg and 1.0 to 1.6 in mid flower, but meters and scales vary. Runoff EC that keeps climbing tells you to water more and feed less.
Organic dry amendments vs bottled nutrients
Dry amendments are slow. They rely on microbes and moisture to release nutrients. Top-dress every 2 to 3 weeks and water them in. Bottled nutrients are immediate. They give you more control, but they can leave salt behind. In soil, I would rather underfeed and correct than overfeed and try to flush a pot full of slow-release fertilizer. Pick a lane.
Signs your schedule needs a change
- Dark green leaves and clawed tips: too much nitrogen. Use plain water for a round.
- Pale lower leaves and slow growth: the plant is hungry. Raise feed strength or top-dress.
- Brown crispy tips: salt burn, dry soil, or a heavy hand with bloom boosters. Check runoff and water deeply.
- Yellow between veins: check pH and magnesium before adding more of everything.
- Purple stems: often genetics or cold nights. Do not treat it as a deficiency without other symptoms.
Water and pH notes for soil
Water slowly enough that the whole pot gets wet. Let the top inch or two dry before the next watering. For soil, aim for water pH around 6.3 to 6.8. That range keeps most nutrients available. Do not chase the perfect number every day. A steady routine beats constant adjustment. If you use tap water, let it sit out if chlorine is high, or use a filter.
Bottom line
In soil, the schedule is slower and more forgiving than hydro. Feed every other watering, top-dress dry amendments every few weeks, keep pH in the low 6s, and watch the plant instead of the calendar. A light hand early and a steady bloom feed later will get you further than a complicated chart.