The Best Nutrients for Autoflowers: A Week-by-Week Feeding Plan

Autoflowers need the same nutrients as any cannabis plant, just less of everything. The best nutrient plan for autos is a base nutrient series at reduced strength - start around one quarter of the bottle chart, shift from nitrogen-heavy to P-K-heavy at first pistils, and let leaf tips tell you when to stop climbing. This page turns that into a week-by-week plan.

The background on what each element does lives in our macronutrients guide and micronutrients guide; this page is the feeding schedule itself.

The week-by-week plan

| Week (from sprout) | Stage | Feeding | |---|---|---| | 1-2 | Seedling | Water only, pH balanced | | 2-4 | Vegetative | Quarter-strength veg nutrients, climbing toward half if leaves stay dark | | 4-5 | Pre-flower | Half-strength veg plus rising P-K, or flower nutes at quarter strength | | 5-8 | Flowering | Half-strength flower nutrients | | 8-10+ | Ripening | Taper; plain pH-balanced water in the final 1-2 weeks |

This is deliberately more conservative than bottle charts, which assume photoperiod plants with long veg. Fast Buds' feeding schedule guide proposes a broadly similar structure - water only in week 1, eighths and quarters through veg, half-strength bloom through flower, and a flush before harvest.

Medium changes the plan

• Pre-fertilised soil: you may not need to feed at all until around week 4. This is the low-risk beginner route, and the reason we recommend fertilised soil in the how to grow guide.
• Plain soil or soil-coco mix: follow the table, erring low. Top-dressing organic feeds follow different rhythms - see the living soil guide.
• Coco and hydro: nutrients start earlier (weeks 1-2 at quarter strength) because the medium holds nothing. Coco also reliably demands calcium and magnesium.

The numbers that make feeding work

Strength alone does not decide what the plant can absorb - pH and EC do. Water at roughly 6.0 to 6.5 pH in soil (5.8 to 6.2 in coco) and keep EC modest: start below 1.0 in seedling and veg, climb toward 1.2 to 1.6 in flower, and watch runoff. Our pH and EC guide is the practical walkthrough, and the additives guide covers Cal-Mag, silica and the rest.

The feeding mistakes that cost the most

1. Following the bottle chart at full strength. The most common cause of burned autos. Quarter strength first.
2. Feeding seedlings. Week 1 plants rarely need anything but water.
3. Ignoring pH while adding nutrients. Lockout looks exactly like deficiency, and the reflex is to feed more, which makes it worse.
4. Pushing nitrogen in flower. Dark, clawed, late plants are usually nitrogen-fat; autos want P-K from first pistils.
5. No taper at the end. A 1 to 2 week plain-water finish is simple and cheap insurance on smoothness.

Choosing a product line

Any reputable two or three part base series (veg and flower) works. Choose by medium first, then by simplicity: a two-bottle system you actually use beats a six-bottle system that intimidates you into guessing. If you prefer no-drip simplicity, living soil with occasional top-dressing is a legitimate philosophy, not a compromise.

For where each feeding stage sits in the grow, see the complete autoflower grow guide; if leaves start complaining mid-grow, the deficiency guide and yellow leaves guide help you read them.

Written by the Autoflower.net Editorial Team. Information on this page is educational and does not replace strain-specific breeder guidance. Laws on cannabis cultivation vary by jurisdiction — check your local rules before growing.