Fertilising guide

How to fertilise Persian lime (Citrus latifolia)— schedule & NPK

Also called Persian lime, Tahiti lime, Bearss lime.

More about persian lime

About Persian lime

Citrus latifolia · also called Persian lime, Tahiti lime · edible

Persian lime is the standard supermarket lime — seedless, thick-skinned, and more cold-hardy than Key lime. It produces heavy, consistent crops of large, juicy limes with a mild, clean flavour. Excellent for container culture in temperate climates with winter protection. Foliage and rind are toxic to pets as with all Citrus.

Growth habit: Evergreen thornless or lightly spined tree

Watch for — Dropped fruit before maturity: Small fruit drop in late spring is normal (June drop equivalent). Excessive fruit drop indicates water stress, low light, or nutrient deficiency. Ensure consistent irrigation and adequate potassium during fruit set.

What fertiliser persian lime actually wants — and why

Persian lime feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

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 persian lime: 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 persian lime, 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 persian lime:

The dormant-season rule matters more than the exact interval: skip feeding entirely when persian lime 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 persian lime

Follow the crop-feed label rate for persian lime — these are calibrated for hungry vegetables. Consistency through fruiting matters more than strength; erratic feeding causes problems like blossom-end rot.

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

Signs you are over-feeding persian lime

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

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen).
Lush foliage hiding the crop; soft growth prone to pests and disease.
Salt crust on the soil and scorched leaf edges in containers.

Signs you are under-feeding persian lime

Pale, yellowing lower leaves and stunted growth.
Small fruit, poor set, and a quickly exhausted plant.
Blossom-end rot and weak cropping from erratic or insufficient feeding.

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

Flushing and leaching the salts

In containers, fertiliser salts build up fast — water persian lime thoroughly so excess drains from the base each time, and flush pots with plain water every few weeks to prevent a damaging salt build-up.

Organic vs synthetic feeds for persian lime

Organic options

Garden compost or well-rotted manure dug in before planting, plus a liquid comfrey or seaweed feed once fruiting starts. UK: comfrey feed or organic Tomorite; US: Espoma Tomato-tone or Neptune's Harvest. Builds soil and feeds in one.

Synthetic / liquid feeds

A balanced feed at planting then a high-potash tomato feed in fruiting — UK: Growmore at planting then Tomorite (Levington) or Phostrogen; US: a balanced 10-10-10 then Miracle-Gro Tomato or a bloom booster.

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 persian lime — frequently asked questions

What fertiliser does persian lime need?

Balanced (even N-P-K) at planting for roots and frame, then switch to a high-potassium ("high-potash") tomato-style feed once the first flowers open — potassium is what sizes and ripens fruit, not nitrogen. Persian lime feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

How often should I feed persian lime?

Apply a specialist citrus fertiliser every 2 weeks from spring through autumn, reducing to monthly or stopping in winter. Include a formulation with chelated iron and magnesium to prevent interveinal chlorosis. Slow-release citrus granules can supplement liquid feeding. Apply a specialist citrus fertiliser every 2 weeks from spring through autumn, reducing to monthly or stopping in winter. Include a formulation with chelated iron and magnesium to prevent interveinal chlorosis. Slow-release citrus granules can supplement liquid feeding. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).

What strength of feed for persian lime?

What does over-feeding persian lime look like?

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen). Lush foliage hiding the crop; soft growth prone to pests and disease. Salt crust on the soil and scorched leaf edges in containers. Staying on a high-nitrogen feed once persian lime starts flowering is the classic error — you get a huge leafy plant and a disappointing crop. Switch to high-potash the moment flowers appear.

Should I flush the soil of persian lime?