Shiso (perilla) care

Light

Most houseplants will scorch where shiso thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Grows best in full sun to light afternoon shade; purple-leaved forms develop the richest colour in full sun. In deep shade it becomes leggy and pale with diminished flavour. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

Aim for keep evenly moist; water when the top 2-3 cm of soil is dry, roughly every 3-5 days in warm weather for shiso, but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. A soft-leaved annual that wilts quickly when dry, so it appreciates consistent moisture. Avoid letting it dry out fully, but ensure good drainage to prevent root rot in soggy soil.

Soil and pot

Shiso grows best in moist, fertile, well-drained loam. Prefers rich, moisture-retentive soil high in organic matter with a pH around 5.5-6.5. Amend with compost before planting; tolerant of a range of soils as long as they stay reasonably moist and drain well. 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

Shiso sits happiest at around 40-70% humidity and 20-30°C (68-86°F). Enjoys the warm, humid conditions of summer and is unfussy about ambient humidity outdoors. The main concern is keeping soil moisture steady rather than managing air humidity. If you keep the room above 20 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 shiso sparingly. Feed lightly every 3-4 weeks during active growth with a balanced or nitrogen-leaning fertiliser to keep leaf production going, or work compost into the bed at planting. Avoid over-feeding, which can soften flavour. 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 shiso in the Growli community. Each is annotated with the most common cause so you know where to start.

• Premature flowering/bolting — As days shorten in late summer the plant bolts to flower and leaf quality declines. Pinch out flower spikes regularly to prolong leaf harvest and prevent excessive self-seeding.
• Aggressive self-seeding — Allowed to flower, shiso scatters seed prolifically and can become weedy. Deadhead flower spikes before seed sets if you want to control spread.
• Wilting from underwatering — The soft foliage flags dramatically the moment soil dries out. Keep moisture consistent and mulch to buffer the root zone in hot weather.
• Slug and snail damage — Young seedlings and tender leaves are a magnet for slugs and snails. Protect emerging plants with barriers or traps, especially in damp spells.

Propagation

Easiest from seed, which needs light to germinate, so surface-sow and barely cover; a brief cold-moist period improves germination. Sow indoors in spring or direct-sow after frost. It also roots readily from softwood cuttings and self-sows freely once established. 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

Shiso is mildly toxic to pets. Perilla frutescens is not clearly verifiable on the ASPCA non-toxic list, and the species is a documented livestock toxin: it contains perilla ketone, which causes acute respiratory distress (atypical interstitial pneumonia) in cattle and horses. For cats and dogs status is uncertain; treat with caution, limit access, and verify with a vet before assuming it is safe. 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.

Shiso deep-dive guides

Every aspect of shiso care, each with its own calibrated guide:

• Shiso watering schedule
• Shiso light requirements
• Best soil mix for shiso
• Shiso fertilizing guide
• When to repot shiso
• How to propagate shiso
• Shiso growth rate & size
• Shiso cold hardiness
• Shiso temperature & humidity
• Is shiso toxic to cats & dogs?
• Is shiso toxic to cats?
• Is shiso toxic to dogs?

Related guides

Shiso is also known as shiso, perilla, and Japanese basil.

• Basil care — light, water and common problems
• Herb garden care — light, water and common problems
• Mint care — light, water and common problems
• All 2464 plant care guides in the Growli library