When should you start feeding cannabis nutrients?
Start cannabis nutrients 10 to 21 days after the seed sprouts, once the plant has its first set of true leaves and two or three nodes. Plants growing in amended soil often coast three to four weeks on what the mix already holds. Coco coir and hydroponic setups need a light feed sooner, often in week one or two at quarter strength.
best cannabis nutrient line schedule
That window is not guesswork. A cannabis seed carries enough stored food to push the seedling through its first leaves, and adding salts before the roots can take them causes more harm than good.
Cannabis Nutrient PPM Schedule
Why seedlings don't need nutrients right away
A germinating seed draws on energy stored in its cotyledons, the two round leaves that open first. Those leaves are not true leaves and they do little photosynthesis. Their job is to feed the plant until real leaves form and roots spread.
- Week 0 to 1: cotyledons supply all the food the seedling needs.
- Week 1 to 2: first true leaves appear with serrated edges.
- Week 2 to 3: cotyledons yellow, shrivel, and drop off.
Once the cotyledons fade, the plant depends on you. Feed too early and salts collect in the root zone, which stalls growth for a week or more.
Week-by-week feeding timeline
Treat this as a starting point, not a fixed clock. Read the plant each week and adjust.
Week 1: plain water
Water only. Keep pH between 6.0 and 6.5 in soil, or 5.5 and 6.0 in coco and hydro. A seedling in a starter plug or solo cup needs a few milliliters, not a soak.
Week 2: watch, don't feed
First true leaves show. If the plant sits in amended soil or a pre-charged plug, it still has food. Plain water remains the right call unless the lower leaves start to pale.
Week 3: first light feed
Two or three nodes is the green light. Mix a quarter of the label's recommended dose. Most base nutrients land near 0.4 to 0.6 EC at that strength.
Week 4: half strength
If the plant grew since the last feed and leaf color holds steady, move to half dose. In coco, water to a little runoff so salts do not collect.
Week 5 and beyond: full vegetative strength
Healthy plants with five or more nodes can take the full recommended vegetative dose. Watch new growth for two days after each jump in strength.
How does the growing medium change the schedule?
The medium matters more than the calendar. Soil holds nutrients and buffers mistakes. Coco and water hold almost nothing, so the plant eats only what you pour in.
- Amended soil: first feed at week 3 or 4, sometimes later.
- Plain potting soil with no added nutrients: week 2 to 3 at quarter strength.
- Coco coir: week 1 to 2, quarter strength, every watering.
- Hydroponics and DWC: week 1, quarter strength, then raise each week.
Do clones and autoflowers follow the same schedule?
Clones have no stored food at all. A rooted cutting needs a light nutrient solution from its first days in the medium, often half of what a seedling gets. Skipping that feed stalls them for weeks.
Autoflowers flower on their own clock, so a heavy early feed can stunt a plant you cannot veg longer to fix. Start autoflowers at quarter strength and stay under half dose through early flower unless the leaves ask for more.
How do you know the plant is ready to eat?
The plant tells you before the calendar does. Look at leaf color, the speed of new growth, and the oldest fan leaves.
- Hungry: lower leaves fade to pale green or yellow while the rest looks fine.
- Ready: steady new growth, deep green leaves, no spots.
- Overfed: tips burn brown, leaves darken and curl down like a claw.
Nutrient burn hits young plants fast because the root ball is small. If you see burnt tips, flush with plain pH-adjusted water and wait a week before feeding again.
What strength should the first feed be?
Quarter strength on the bottle label is the safe start. For most two-part and three-part base nutrients, that lands around 200 to 350 PPM on the 500 scale, or 0.4 to 0.6 EC.
Skip additives in the first month. Bloom boosters, PK additives, and enzymes do nothing useful for a plant that has not started flowering.
When do you switch to bloom nutrients?
Switch when you flip the light cycle to 12/12, or when an autoflower shows its first pistils. Hold the vegetative dose through the stretch, then move to bloom ratios in week two or three of flower.
Common mistakes with early feeding
- Feeding on a fixed day instead of reading the plant.
- Full-strength nutrients at the first sign of true leaves.
- Ignoring pH, which locks out nutrients even when the dose is right.
- Adding calmag, bloom boosters, and root tonics all at once.
- Soaking a dry seedling and drowning the young roots.
FAQ
Can I start nutrients at week one?
In coco or hydro, yes, at quarter strength. In soil, no. The mix already feeds the plant and early salts can burn new roots.
How long can a cannabis seedling go without nutrients?
Two to three weeks in most setups, and up to four weeks in rich amended soil. After the cotyledons drop, the stored food runs out.
What does nutrient burn look like on a seedling?
Crisp brown tips on the newest leaves, dark green color, and downward curling. Flush with plain water and cut the dose by half.
Should I feed a plant every watering?
In coco and hydro, yes, at the correct strength. In soil, feed every other watering and give plain water in between.