What Is the Best Fertilizer for Alocasia?

The best all-round fertiliser for Alocasia is a balanced, micronutrient-complete liquid. Our top choice is CompleteGrow All Purpose Liquid NPK 20-20-20 — it delivers even N-P-K plus iron, magnesium, and boron for steady leaf expansion, strong petioles, and rich colour without salt burn.

At a Glance: Alocasia Feeding

Best product: CompleteGrow 20-20-20 (with micros)
Active season (spring–early autumn): 2–3 ml/L every 7–14 days (soil drench)
Dormant/cool months: Feed lightly: 1 ml/L every 4–6 weeks, or pause if growth stops
Water quality: Use rain/filtered water; add Ca/Mg if using very soft or RO water
pH targets: Potting mix runoff ~5.8–6.5 for best nutrient uptake
Flush rule: Rinse pot thoroughly with plain water every 6–8 weeks to prevent salt build-up

Quick Fix: Pale leaves or stalled growth? Resume feeding at 2 ml/L with CompleteGrow 20-20-20, raise light to bright-indirect, and keep the mix evenly moist (never waterlogged).

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Why Balanced 20-20-20 Works for Alocasia

Nitrogen (N): drives chlorophyll and rapid lamina expansion — too little = small, pale leaves; too much = floppy tissue and salt stress.

Phosphorus (P): supports root/rhizome energy and new leaf primordia; deficiency stalls flushes.

Potassium (K): regulates stomata and cell turgor; deficiency shows as margin scorch and weak petioles. A 1:1:1 like 20-20-20 supplies each macro evenly so you can dial dose by season without skewing growth.

Micros that Matter (Houseplant Reality)

Iron (Fe): prevents new-leaf interveinal chlorosis in high-light setups; chelated Fe in complete feeds keeps colour rich.
Magnesium (Mg): central to chlorophyll; low Mg → yellowing between veins on older leaves. 20-20-20 covers base needs; foliar Mg can correct fast.
Calcium (Ca) & Boron (B): critical at meristems. Soft/RO water users should add a small Ca/Mg supplement to avoid deformed or tearing new leaves.

Exact Feeding Programs (Soil, Semi-Hydro, Prop)

Standard potting mix (indoor, bright-indirect): 2–3 ml/L CompleteGrow 20-20-20 every 7–14 days in warm months; 1 ml/L every 4–6 weeks in winter if still pushing leaves.
High light / warm conservatory: Stay at the weekly end (2–3 ml/L). Increase watering cadence, not strength, to avoid EC spikes.
Semi-hydro / LECA: Reservoir solution at ~1.0–1.2 mS/cm (roughly 1–1.5 ml/L of 20-20-20, adjust by meter). Refresh every 1–2 weeks. Add Ca/Mg for RO water.
Fresh divisions / rehab plants: First 2–3 weeks: 0.5–1 ml/L only; step up as new roots form.

Salinity control: Alocasia are salt-sensitive. If leaf tips brown or edges crisp after feeds, flush the pot and drop back to 1–2 ml/L for the next two waterings.

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When It’s Not the Fertiliser

Low light: Leads to small leaves and long petioles no matter the feed. Move to bright-indirect (near an east or filtered north window).
Cold roots: Below ~16°C soil temps, uptake slows; fertiliser can accumulate. Warm the room/mix and reduce frequency.
Wet feet: Soggy mixes cause chlorosis that looks like deficiency. Improve drainage (chunky aroid mix) and water when the top 2–3 cm are just dry.
Humidity: Aim 50–70%. Very dry air → torn margins and stalled unfurling despite perfect nutrition.

Deficiency Signals & Fast Fixes

Uniform paling (older leaves first): Mild N shortage → resume 2–3 ml/L weekly.
Edge scorch / weak petioles: K shortage or salt build-up → flush pot, feed 2 ml/L next watering.
New leaves yellow between veins: Fe or Mg issue → ensure pH ≤6.5; add Fe-chelate or foliar Mg; continue balanced feed.
Deformed new growth: Ca/B shortfall (often soft/RO water) → add light Ca/Mg supplement; avoid over-drying between waterings.

FAQs

Do Alocasias need a “bloom booster” (high-P) fertiliser? Not necessary. A complete 20-20-20 supports rhizome and leaf production without skewing salts.
Can I foliar feed? Yes — mist at 0.5–1 ml/L on the undersides in the morning, then resume soil feeding as normal.
How often should I repot? Every 12–18 months into a chunky aroid mix; reset salts and resume the standard program.
Is organic feed better? Organics are fine but slower indoors; a clean, complete liquid like CompleteGrow 20-20-20 is easier to dose and won’t smell in living spaces.