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Fertilising guide

How to fertilise Iris 'Katharine Hodgkin' (Iris 'Katharine Hodgkin')— schedule & NPK

Also called Katharine Hodgkin iris, dwarf reticulata iris, blue yellow miniature iris.

More about iris 'katharine hodgkin'

About Iris 'Katharine Hodgkin'

Iris 'Katharine Hodgkin' · also called Katharine Hodgkin iris, dwarf reticulata iris · flowering

Iris 'Katharine Hodgkin' is a beloved dwarf reticulata iris flowering in late winter, with intricate pale ice-blue and primrose-yellow blooms veined and dotted in deeper blue. Plant the small bulbs in autumn in full sun and gritty, free-draining soil. At just 10-15 cm tall, it shines in rockeries, troughs and at the front of borders.

Growth habit: Small bulbous perennial producing narrow upright leaves and a single intricately patterned flower per bulb in late winter, multiplying slowly into clumps.

Watch for — Bulb splitting into non-flowering grass: Bulbs can break into many small offsets that produce only leaves; feed with potassium after flowering and grow lean to maintain flowering size.

What fertiliser iris 'katharine hodgkin' actually wants — and why

Iris 'Katharine Hodgkin' 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 iris 'katharine hodgkin': 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 iris 'katharine hodgkin', 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 iris 'katharine hodgkin':

Apply a low-nitrogen, high-potassium feed such as a tomato-type fertiliser as growth begins and again after flowering to build the bulb for next season. Avoid rich or high-nitrogen feeds, which favour leaf over flower and encourage rot. Treat that as sparingly through the growing season 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 iris 'katharine hodgkin' 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 iris 'katharine hodgkin'

Half strength is the safe default for iris 'katharine hodgkin' — 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 iris 'katharine hodgkin' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the iris 'katharine hodgkin' watering schedule.

Signs you are over-feeding iris 'katharine hodgkin'

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

Signs you are under-feeding iris 'katharine hodgkin'

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

Flushing and leaching the salts

Flush the pot of iris 'katharine hodgkin' 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 iris 'katharine hodgkin'

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 iris 'katharine hodgkin' — frequently asked questions

What fertiliser does iris 'katharine hodgkin' 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. Iris 'Katharine Hodgkin' 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 iris 'katharine hodgkin'?

Apply a low-nitrogen, high-potassium feed such as a tomato-type fertiliser as growth begins and again after flowering to build the bulb for next season. Avoid rich or high-nitrogen feeds, which favour leaf over flower and encourage rot. Apply a low-nitrogen, high-potassium feed such as a tomato-type fertiliser as growth begins and again after flowering to build the bulb for next season. Avoid rich or high-nitrogen feeds, which favour leaf over flower and encourage rot. Treat that as sparingly through the growing season 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 iris 'katharine hodgkin'?

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

What does over-feeding iris 'katharine hodgkin' 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 iris 'katharine hodgkin' 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 iris 'katharine hodgkin'?

Flush the pot of iris 'katharine hodgkin' 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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