Fertilising guide
How to fertilise Lemon Thyme (Thymus × citriodorus)— schedule & NPK
Also called Lemon Thyme, Citrus Thyme.
More about lemon thyme
About Lemon Thyme
Thymus × citriodorus · also called Lemon Thyme, Citrus Thyme · herb
Lemon Thyme is a hybrid between Thymus vulgaris and Thymus pulegioides, producing a low, mounding sub-shrub with a fresh lemon-thyme scent. Available in green, gold-variegated, and silver-edged forms, it doubles as an ornamental ground cover. Hardy and drought-tolerant once established, it performs best in full sun with sharply drained soil.
Growth habit: Low-mounding, woody-based sub-shrub; slightly more spreading than common thyme with soft, small ovate leaves; pale lilac to pink flowers in early summer
What fertiliser lemon thyme actually wants — and why
Lemon Thyme is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed.
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 lemon thyme: 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 lemon thyme, 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 lemon thyme:
Apply a light dressing of balanced granular fertiliser in early spring only. Over-fertilising weakens the plant's aromatic profile. The hybrid's variegated cultivars can revert to green if pushed with high-nitrogen feeds — minimal feeding preserves both fragrance and leaf colour. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
The dormant-season rule matters more than the exact interval: skip feeding entirely when lemon thyme 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 lemon thyme
Half strength is a sensible default for lemon thyme — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
Feeding always goes onto already-damp soil, never dry roots — water lemon thyme first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the lemon thyme watering schedule.
Signs you are over-feeding lemon thyme
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for lemon thyme:
- Fast, soft, pale growth with diluted, less aromatic flavour.
- Early bolting (running to flower) and a bitter edge.
- Salt crust and scorched tips on container plants.
Signs you are under-feeding lemon thyme
- Pale, slow regrowth after cutting and small leaves.
- A tired, stalled plant that cannot keep up with harvesting.
- Yellowing older leaves in a long-spent pot.
If the symptoms point at watering, light or roots rather than nutrition, the full lemon thyme care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Pot-grown lemon thyme builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Organic vs synthetic feeds for lemon thyme
Organic options
A diluted seaweed feed or worm-casting tea keeps soft growth coming without overdoing it. UK: dilute seaweed or Westland; US: Espoma Garden-tone or Neptune's Harvest. Gentle, hard to overdo, flavour-friendly.
Synthetic / liquid feeds
A balanced liquid feed at half strength through harvesting — UK: Phostrogen, Baby Bio or Westland; US: Miracle-Gro all-purpose at half strength. Fast regrowth; just do not overdo the nitrogen.
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 lemon thyme — frequently asked questions
What fertiliser does lemon thyme need?
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed. Lemon Thyme is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
How often should I feed lemon thyme?
Apply a light dressing of balanced granular fertiliser in early spring only. Over-fertilising weakens the plant's aromatic profile. The hybrid's variegated cultivars can revert to green if pushed with high-nitrogen feeds — minimal feeding preserves both fragrance and leaf colour. Apply a light dressing of balanced granular fertiliser in early spring only. Over-fertilising weakens the plant's aromatic profile. The hybrid's variegated cultivars can revert to green if pushed with high-nitrogen feeds — minimal feeding preserves both fragrance and leaf colour. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
What strength of feed for lemon thyme?
Half strength is a sensible default for lemon thyme — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
What does over-feeding lemon thyme look like?
Fast, soft, pale growth with diluted, less aromatic flavour. Early bolting (running to flower) and a bitter edge. Salt crust and scorched tips on container plants. Over-feeding lemon thyme with strong nitrogen is the usual mistake — it grows fast and lush but the leaves turn bland and it bolts to flower sooner, ending the useful harvest early.
Should I flush the soil of lemon thyme?
Pot-grown lemon thyme builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Keep reading
- Lemon Thyme care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water lemon thyme — 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 cinnamon basil
- How to fertilise african blue basil
- How to fertilise greek bush basil
- All 6887 fertilising guides in the Growli library