Fertilising guide
How to fertilise Sea Bindweed (Calystegia soldanella)— schedule & NPK
Also called Sea bindweed, Shore bindweed, Seashore false bindweed.
More about sea bindweed
About Sea Bindweed
Calystegia soldanella · also called Sea bindweed, Shore bindweed · flowering
Calystegia soldanella is a prostrate perennial native to sand dunes and coastal shingle across the British Isles, Europe, North America, and temperate coasts worldwide. It spreads by creeping rhizomes just below the sand surface, producing kidney-shaped, fleshy, glaucous leaves and beautiful pink trumpet flowers with white stripes from June to August. The key challenge in cultivation is recreating its open, sunny, sharply drained coastal habitat — it is notoriously difficult to establish in a garden setting. Toxicity to cats and dogs is not confirmed by ASPCA; related Convolvulaceae may contain alkaloids, so treat as mildly toxic as a precaution.
Growth habit: Prostrate perennial ground-cover spreading by surface-creeping and underground rhizomes; leaves and flowers rise just 5–10 cm above ground.
What fertiliser sea bindweed actually wants — and why
Sea Bindweed 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 sea bindweed: 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 sea bindweed, 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 sea bindweed:
Do not fertilise; this is a natural coloniser of nutrient-poor coastal sands and richer soils simply promote weedy competition and reduce the plant's vigour. 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 sea bindweed 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 sea bindweed
Half strength is the safe default for sea bindweed — 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 sea bindweed first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the sea bindweed watering schedule.
Signs you are over-feeding sea bindweed
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for sea bindweed:
- 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.
Signs you are under-feeding sea bindweed
- Uniformly pale or yellow-green leaves, oldest first.
- Noticeably small new leaves and stalled growth in good light and season.
- A generally tired, lacklustre look despite correct watering and light.
If the symptoms point at watering, light or roots rather than nutrition, the full sea bindweed care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of sea bindweed 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 sea bindweed
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 sea bindweed — frequently asked questions
What fertiliser does sea bindweed 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. Sea Bindweed 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 sea bindweed?
Do not fertilise; this is a natural coloniser of nutrient-poor coastal sands and richer soils simply promote weedy competition and reduce the plant's vigour. Do not fertilise; this is a natural coloniser of nutrient-poor coastal sands and richer soils simply promote weedy competition and reduce the plant's vigour. 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 sea bindweed?
Half strength is the safe default for sea bindweed — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding sea bindweed 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 sea bindweed 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 sea bindweed?
Flush the pot of sea bindweed 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.
Keep reading
- Sea Bindweed care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water sea bindweed — 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 peregrina
- How to fertilise sheerwater seedling rowan
- How to fertilise cardinal royal rowan
- All 10153 fertilising guides in the Growli library