Sweet Pea 'Spencer' (Spencer sweet pea) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun for at least 6 hours keeps stems strong and flowering heavy. Cool, shaded roots prevent early decline in warmer climates. If your only bright window faces south, that's perfect for sweet pea 'spencer' — same window any aroid would fry on.

Watering

Watering sweet pea 'spencer': every 2-3 days, keeping soil consistently moist. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Generous, regular watering supports the long cutting stems and prevents bud drop. Water at the base in the morning to keep foliage dry.

Soil and pot

Sweet Pea 'Spencer' grows best in deep, fertile, well-drained loam. Heavily enriched with compost or rotted manure, near-neutral to slightly alkaline (pH 6.5-7.5). Prepare a deep trench so the long roots have ample fertile soil. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Sweet Pea 'Spencer' sits happiest at around 40-60% humidity and 10-18°C (50-65°F). Outdoor ambient humidity suits them. Good spacing and airflow reduce powdery mildew on the dense exhibition foliage. If you keep the room above 10 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed sweet pea 'spencer' sparingly. High-potash liquid feed (tomato-type) every 1-2 weeks through flowering. For show-quality stems, exhibitors grow on single cordons and feed steadily; avoid heavy nitrogen. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on sweet pea 'spencer' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Powdery mildew — Dense exhibition foliage is prone to white mildew late in the season. Space plants, water at the base, and improve ventilation.
• Bud drop — Caused by dry roots, temperature swings or overcrowding. Maintain even moisture and steady feeding to hold buds.
• Slugs and snails — Devour young seedlings and shoots. Protect early growth with barriers or traps.
• Weak or short stems — Poor soil or too much heat shortens the prized cutting stems. Enrich soil deeply, keep roots cool, and cordon-train for length.

Propagation

From seed only. Chip or soak hard-coated seeds, sow autumn or late winter under cover, pinch at 10 cm for branching (or grow on as single cordons for exhibition), and deadhead continuously. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Sweet Pea 'Spencer' is mildly toxic to pets. As a Lathyrus odoratus cultivar, it is not covered by the ASPCA 'Sweet Pea' non-toxic listing (which applies to L. latifolius). The seeds and pods contain a lathyrogen (aminopropionitrile) and can cause toxicity if eaten; treat with caution and verify with a vet. Keep the developing seed pods away from pets and children. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Sweet Pea 'Spencer' deep-dive guides

Every aspect of sweet pea 'spencer' care, each with its own calibrated guide:

• Sweet Pea 'Spencer' watering schedule
• Sweet Pea 'Spencer' light requirements
• Best soil mix for sweet pea 'spencer'
• Sweet Pea 'Spencer' fertilizing guide
• When to repot sweet pea 'spencer'
• How to propagate sweet pea 'spencer'
• Sweet Pea 'Spencer' growth rate & size
• Sweet Pea 'Spencer' cold hardiness
• Sweet Pea 'Spencer' temperature & humidity
• Is sweet pea 'spencer' toxic to cats & dogs?
• Is sweet pea 'spencer' toxic to cats?
• Is sweet pea 'spencer' toxic to dogs?
• Getting sweet pea 'spencer' to bloom

Featured in these plant shortlists

Sweet Pea 'Spencer' qualifies for 7 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best trailing & climbing houseplants — Vining and trailing houseplants for shelves, hanging pots, and moss poles — selected by growth habit.
• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Best fast-growing houseplants — Houseplants documented as fast or vigorous growers — quick to fill a pot, cover a pole or trail down a shelf.
• Best fragrant houseplants — Indoor plants with scented flowers or aromatic foliage — greenery you can smell, selected from our care library.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Sweet Pea 'Spencer' is also commonly called Spencer sweet pea.

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