Fertilising guide
How to fertilise 'Scarlet Runner' Bean (Phaseolus coccineus 'Scarlet Emperor')— schedule & NPK
Also called Runner bean, Scarlet runner bean.
More about 'scarlet runner' bean
About 'Scarlet Runner' Bean
Phaseolus coccineus 'Scarlet Emperor' · also called Runner bean, Scarlet runner bean · edible
'Scarlet Emperor' is a vigorous climbing runner bean (Phaseolus coccineus) prized for both its showy scarlet flowers and long, flat green pods. A tender perennial grown as an annual, it twines several metres up supports in a single season. Sow after frost, train up canes or netting, and pick pods young for the most tender, stringless beans.
Growth habit: Vigorous twining herbaceous climber; left-handed stems spiral up vertical supports, reaching full height in one season from a fleshy perennial rootstock.
Watch for — Halo blight: Angular leaf spots with pale yellow halos in cool wet seasons; remove affected leaves, avoid overhead watering and use clean seed.
What fertiliser 'scarlet runner' bean actually wants — and why
'Scarlet Runner' Bean is grown entirely for its leaves, so nitrogen is the priority — steady, nitrogen-leaning feeding keeps it growing fast, tender and unbolted.
A nitrogen-leaning feed (higher first number) or compost-rich soil — nitrogen drives the fast, tender leafy growth this crop is grown for. Phosphorus and potassium matter far less here than for fruiting crops.
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 'scarlet runner' bean: 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 'scarlet runner' bean, 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 'scarlet runner' bean:
A fertile soil usually carries the crop; avoid high-nitrogen feeds that push leaf over flower. A high-potash feed (as for tomatoes) every 2 weeks once flowering supports continued pod set. In practice: a balanced or compost-rich start, then a nitrogen side-dress or liquid feed every 3-4 weeks through the cropping period in the main season (spring through early autumn).
The dormant-season rule matters more than the exact interval: skip feeding entirely when 'scarlet runner' bean 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 'scarlet runner' bean
Use the vegetable-feed label rate for 'scarlet runner' bean. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.
Feeding always goes onto already-damp soil, never dry roots — water 'scarlet runner' bean first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the 'scarlet runner' bean watering schedule.
Signs you are over-feeding 'scarlet runner' bean
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for 'scarlet runner' bean:
- Very soft, floppy, dark-green growth that attracts aphids.
- Excess leafy growth at the expense of hearts/heads in cabbage and the like.
- Salt crust and scorched leaf edges in containers; nitrate-heavy leaves.
Signs you are under-feeding 'scarlet runner' bean
- Pale, yellow-green leaves, oldest first, and slow growth.
- Small, tough, bitter leaves and premature bolting.
- Weak, stunted heads in cabbage, broccoli and cauliflower.
If the symptoms point at watering, light or roots rather than nutrition, the full 'scarlet runner' bean care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
For container-grown 'scarlet runner' bean, water until it drains freely each time and flush pots monthly with plain water to stop nitrogen salts accumulating; in the ground, good compost levels naturally buffer this.
Organic vs synthetic feeds for 'scarlet runner' bean
Organic options
Well-rotted manure or compost dug in, plus nitrogen-rich liquid feeds like diluted chicken-manure pellets or nettle feed. UK: pelleted chicken manure or Westland; US: Espoma Garden-tone or blood meal. Steady and soil-building.
Synthetic / liquid feeds
A balanced feed at planting then a high-nitrogen liquid or granular side-dress — UK: Growmore then a nitrogen feed or Phostrogen; US: a 10-10-10 then a high-N (e.g. 21-0-0) side-dress or Miracle-Gro.
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 'scarlet runner' bean — frequently asked questions
What fertiliser does 'scarlet runner' bean need?
A nitrogen-leaning feed (higher first number) or compost-rich soil — nitrogen drives the fast, tender leafy growth this crop is grown for. Phosphorus and potassium matter far less here than for fruiting crops. 'Scarlet Runner' Bean is grown entirely for its leaves, so nitrogen is the priority — steady, nitrogen-leaning feeding keeps it growing fast, tender and unbolted.
How often should I feed 'scarlet runner' bean?
A fertile soil usually carries the crop; avoid high-nitrogen feeds that push leaf over flower. A high-potash feed (as for tomatoes) every 2 weeks once flowering supports continued pod set. A fertile soil usually carries the crop; avoid high-nitrogen feeds that push leaf over flower. A high-potash feed (as for tomatoes) every 2 weeks once flowering supports continued pod set. In practice: a balanced or compost-rich start, then a nitrogen side-dress or liquid feed every 3-4 weeks through the cropping period in the main season (spring through early autumn).
What strength of feed for 'scarlet runner' bean?
Use the vegetable-feed label rate for 'scarlet runner' bean. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.
What does over-feeding 'scarlet runner' bean look like?
Very soft, floppy, dark-green growth that attracts aphids. Excess leafy growth at the expense of hearts/heads in cabbage and the like. Salt crust and scorched leaf edges in containers; nitrate-heavy leaves. Letting 'scarlet runner' bean run short of nitrogen mid-crop is the main mistake — growth checks, leaves toughen and brassicas/leafy greens bolt or turn bitter. Keep nitrogen steadily available.
Should I flush the soil of 'scarlet runner' bean?
For container-grown 'scarlet runner' bean, water until it drains freely each time and flush pots monthly with plain water to stop nitrogen salts accumulating; in the ground, good compost levels naturally buffer this.
Keep reading
- 'Scarlet Runner' Bean care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water 'scarlet runner' bean — 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 tomato
- How to fertilise pepper
- How to fertilise cucumber
- All 1284 fertilising guides in the Growli library