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Fertilising guide

How to fertilise Moonflower (Ipomoea alba)— schedule & NPK

Also called Moonflower, Moon vine, Tropical white morning glory.

More about moonflower

About Moonflower

Ipomoea alba · also called Moonflower, Moon vine · flowering

Moonflower is a fast-growing night-blooming vine producing large, intensely fragrant white flowers up to 6 inches across that open at dusk. Grow in full sun on a sturdy support. Treat as an annual in temperate climates; seeds require nicking before sowing. Keep away from pets — seeds contain hallucinogenic indole alkaloids.

Growth habit: Vigorous twining vine

Watch for — Poor or absent flowering: Almost always caused by excess nitrogen, insufficient sun, or soil that is too rich. Switch to a low-nitrogen fertiliser and ensure a minimum of 6 hours of direct sun.

What fertiliser moonflower actually wants — and why

Moonflower is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.

A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula.

For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for moonflower: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.

How often to feed moonflower, and which months

Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For moonflower:

Feed monthly during the growing season with a balanced or low-nitrogen fertiliser (e.g., 5-10-10) to encourage blooms over foliage. Excess nitrogen delays flowering. Treat that as monthly between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.

The dormant-season rule matters more than the exact interval: skip feeding entirely when moonflower is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.

What strength to mix for moonflower

Half strength is the safe default for moonflower — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

Feeding always goes onto already-damp soil, never dry roots — water moonflower first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the moonflower watering schedule.

Signs you are over-feeding moonflower

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for moonflower:

Signs you are under-feeding moonflower

If the symptoms point at watering, light or roots rather than nutrition, the full moonflower care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Flush the pot of moonflower with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.

Organic vs synthetic feeds for moonflower

Organic options

A diluted seaweed or worm-casting feed, or fish emulsion if you can tolerate the smell indoors. UK: Westland or Baby Bio Organic, dilute seaweed; US: Espoma Indoor! or Neptune's Harvest fish & seaweed. Slow, gentle and hard to overdo.

Synthetic / liquid feeds

A general-purpose houseplant liquid at half strength — UK: Baby Bio, Westland Houseplant Feed or Phostrogen; US: Miracle-Gro Indoor Plant Food or Schultz. Convenient and fast-acting; the only risk is overdoing it.

Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.

Fertilising moonflower — frequently asked questions

What fertiliser does moonflower need?

A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula. Moonflower is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.

How often should I feed moonflower?

Feed monthly during the growing season with a balanced or low-nitrogen fertiliser (e.g., 5-10-10) to encourage blooms over foliage. Excess nitrogen delays flowering. Feed monthly during the growing season with a balanced or low-nitrogen fertiliser (e.g., 5-10-10) to encourage blooms over foliage. Excess nitrogen delays flowering. Treat that as monthly between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.

What strength of feed for moonflower?

Half strength is the safe default for moonflower — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.

What does over-feeding moonflower look like?

Brown, crispy leaf tips and edges with no sign of underwatering. A white, crusty salt deposit on the soil surface or pot rim. Weak, pale, stretched new growth that flops. Lower leaves yellow and drop while the soil is correctly watered. Feeding moonflower year-round on a fixed schedule, including dark winter months, is the most common mistake — it cannot use the nutrients in low light and the surplus simply burns the roots and crusts the soil.

Should I flush the soil of moonflower?

Flush the pot of moonflower with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.

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