Fertilising guide
How to fertilise Chrysanthemum (Chrysanthemum × morifolium)— schedule & NPK
Also called florist's chrysanthemum, pot mum, garden mum.
More about chrysanthemum
About Chrysanthemum
Chrysanthemum × morifolium · also called florist's chrysanthemum, pot mum · flowering
Chrysanthemum × morifolium, the florist's or garden mum, is a hardy to half-hardy perennial grown for its profuse autumn flowers in nearly every colour and form, from daisy-like singles to dense pompons. Short-day flowering triggers its display as nights lengthen. Widely sold as pot plants and bedding, mums need full sun, fertile soil, and steady moisture for the best bloom.
Growth habit: Bushy, branching herbaceous perennial; pinching young shoots encourages a dense, well-branched mound smothered in autumn flowers.
Watch for — Aphids and chrysanthemum leaf miner: Aphids cluster on buds; leaf-miner larvae tunnel pale trails in leaves. Inspect regularly and remove or treat infested growth.
What fertiliser chrysanthemum actually wants — and why
Chrysanthemum is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.
A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom.
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 chrysanthemum: 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 chrysanthemum, 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 chrysanthemum:
Feed every 1-2 weeks during active growth with a balanced fertiliser, switching to a high-potash feed as buds form to boost flowering. Stop feeding once blooms open and through winter dormancy. For a hungry bloomer that means feeding regularly — every 1-2 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.
The dormant-season rule matters more than the exact interval: skip feeding entirely when chrysanthemum 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 chrysanthemum
Follow the flowering-feed label rate for chrysanthemum, or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.
Feeding always goes onto already-damp soil, never dry roots — water chrysanthemum first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the chrysanthemum watering schedule.
Signs you are over-feeding chrysanthemum
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for chrysanthemum:
- Lots of lush leaves but few flowers (too much nitrogen).
- Scorched leaf edges and salt crust from too-strong or too-frequent feeds.
- Soft, sappy growth prone to aphids and mildew.
Signs you are under-feeding chrysanthemum
- Sparse, small, short-lived flowers and pale foliage.
- A tired plant that stops blooming early in the season.
- Weak growth and poor repeat-flowering after the first flush.
If the symptoms point at watering, light or roots rather than nutrition, the full chrysanthemum care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Container-grown chrysanthemum accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.
Organic vs synthetic feeds for chrysanthemum
Organic options
A liquid comfrey or seaweed feed (naturally potassium-rich) plus compost or well-rotted manure as a mulch. UK: comfrey feed, organic Tomorite, or rose feed; US: Espoma Rose-tone or Neptune's Harvest. Feeds and improves soil.
Synthetic / liquid feeds
A high-potash flowering feed on a regular cadence — UK: Tomorite (Levington), Phostrogen or a specialist rose feed; US: Miracle-Gro Bloom Booster or a rose food. Fast, reliable bloom response.
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 chrysanthemum — frequently asked questions
What fertiliser does chrysanthemum need?
A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom. Chrysanthemum is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.
How often should I feed chrysanthemum?
Feed every 1-2 weeks during active growth with a balanced fertiliser, switching to a high-potash feed as buds form to boost flowering. Stop feeding once blooms open and through winter dormancy. Feed every 1-2 weeks during active growth with a balanced fertiliser, switching to a high-potash feed as buds form to boost flowering. Stop feeding once blooms open and through winter dormancy. For a hungry bloomer that means feeding regularly — every 1-2 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.
What strength of feed for chrysanthemum?
Follow the flowering-feed label rate for chrysanthemum, or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.
What does over-feeding chrysanthemum look like?
Lots of lush leaves but few flowers (too much nitrogen). Scorched leaf edges and salt crust from too-strong or too-frequent feeds. Soft, sappy growth prone to aphids and mildew. Using a high-nitrogen general feed on chrysanthemum is the headline mistake — you grow a big leafy plant with few flowers. The second is simply under-feeding a genuinely hungry bloomer and getting a sparse, short display.
Should I flush the soil of chrysanthemum?
Container-grown chrysanthemum accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.
Keep reading
- Chrysanthemum care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water chrysanthemum — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise peace lily
- How to fertilise bird of paradise
- How to fertilise hoya
- All 2464 fertilising guides in the Growli library