Fertilising guide
How to fertilise Lettuce Leaf Basil (Ocimum basilicum 'Napoletano')— schedule & NPK
Also called lettuce leaf basil, Neapolitan basil.
More about lettuce leaf basil
About Lettuce Leaf Basil
Ocimum basilicum 'Napoletano' · also called lettuce leaf basil, Neapolitan basil · herb
Lettuce leaf basil is a large-leaved Italian sweet basil whose huge, crinkled, lettuce-like leaves are ideal for wrapping and tearing into salads. A tender warm-season annual, it demands heat, full sun and rich, moist soil, grows vigorously, and is best kept productive by frequent harvesting and pinching out flowers before it bolts.
Growth habit: A robust, upright tender annual herb with very large, broad, puckered bright-green leaves; sends up white flower spikes that must be pinched off to keep the plant leafy and extend the cropping season.
What fertiliser lettuce leaf basil actually wants — and why
Lettuce Leaf Basil 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 lettuce leaf basil: 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 lettuce leaf basil, 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 lettuce leaf basil:
A vigorous feeder given its leaf size. Start in rich soil and feed every 2-3 weeks with a balanced liquid feed leaning slightly to nitrogen to keep producing big, tender leaves. Ease off as flowering approaches; excess feed thins the flavour. 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 lettuce leaf basil 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 lettuce leaf basil
Half strength is a sensible default for lettuce leaf basil — 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 lettuce leaf basil first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the lettuce leaf basil watering schedule.
Signs you are over-feeding lettuce leaf basil
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for lettuce leaf basil:
- 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 lettuce leaf basil
- 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 lettuce leaf basil care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Pot-grown lettuce leaf basil 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 lettuce leaf basil
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 lettuce leaf basil — frequently asked questions
What fertiliser does lettuce leaf basil 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. Lettuce Leaf Basil 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 lettuce leaf basil?
A vigorous feeder given its leaf size. Start in rich soil and feed every 2-3 weeks with a balanced liquid feed leaning slightly to nitrogen to keep producing big, tender leaves. Ease off as flowering approaches; excess feed thins the flavour. A vigorous feeder given its leaf size. Start in rich soil and feed every 2-3 weeks with a balanced liquid feed leaning slightly to nitrogen to keep producing big, tender leaves. Ease off as flowering approaches; excess feed thins the flavour. 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 lettuce leaf basil?
Half strength is a sensible default for lettuce leaf basil — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
What does over-feeding lettuce leaf basil 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 lettuce leaf basil 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 lettuce leaf basil?
Pot-grown lettuce leaf basil 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
- Lettuce Leaf Basil care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water lettuce leaf basil — 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 basil
- How to fertilise herb garden
- How to fertilise mint
- All 2464 fertilising guides in the Growli library