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Light requirements

How much light does Tat Soi 'Yukina Savoy' (Brassica rapa var. narinosa 'Yukina Savoy') need?

Also called Yukina Savoy, savoy tatsoi, Japanese savoy mustard.

More about tat soi 'yukina savoy'

About Tat Soi 'Yukina Savoy'

Brassica rapa var. narinosa 'Yukina Savoy' · also called Yukina Savoy, savoy tatsoi · edible

'Yukina Savoy' is an upright, cold-hardy Asian green, a heat-tolerant tatsoi type with thick, blistered (savoyed) dark-green leaves on pale stems. Mild and slightly mustardy, it crops fast in cool weather, resists bolting better than flat tatsoi, and sweetens after light frost. Harvest as cut-and-come-again baby leaf or as full rosettes.

Comfort temperature: 10-22°C

The exact light tat soi 'yukina savoy' needs

Tat Soi 'Yukina Savoy' is a sun-driven crop — yield is directly limited by how much direct sun it gets, so this is one plant where "more light, more harvest" is literally true.

Put a number on it — this is what a meter (or a free phone light-meter app) should read where tat soi 'yukina savoy' sits:

In plain terms, Full sun outdoors: an open spot that gets 6–8 hours of unobstructed direct sun, ideally including midday. Indoors or on a windowsill it needs the brightest south-facing position you have and usually still benefits from a grow light. Shaded beds, north-facing walls, and gappy "dappled" light — these grow lush leaves but little or poor-quality crop.

Not sure how to read the light in your home? Our light meter guide walks through measuring footcandles and lux with a free phone app and turning the reading into a placement decision for tat soi 'yukina savoy'.

Signs tat soi 'yukina savoy' is getting too much light

The most exposed leaves show it first. For tat soi 'yukina savoy' specifically, watch for:

Light damage does not heal — a scorched leaf stays scorched — so the fix is to move tat soi 'yukina savoy' out of the harsh light rather than wait for it to recover.

Signs tat soi 'yukina savoy' is not getting enough light

Too little light is slower and sneakier than too much. The classic tell is etiolation: the plant stretches and pales as it reaches for a window. For tat soi 'yukina savoy', look for:

If tat soi 'yukina savoy' is stretched, leggy and pale, our guide to leggy, stretched plants covers how to fix it and whether it can be pruned back into shape. Tucking tat soi 'yukina savoy' into a part-shade corner and expecting a full crop. Leafy growth tolerates some shade, but fruit, roots and flavour are paid for in hours of direct sun — short the light and you short the harvest.

Where to put tat soi 'yukina savoy': the best window and room

Give tat soi 'yukina savoy' the sunniest open ground or the largest container in the brightest spot you have. A south-facing wall, allotment in the open, or unshaded raised bed is ideal. If you are growing it indoors or on a balcony, a full-spectrum grow light is usually not optional but essential — a windowsill alone rarely ripens a sun crop well.

  1. Pick the sunniest position. Site tat soi 'yukina savoy' where it gets 6–8 hours of direct sun — open ground or the brightest container spot, away from walls and tree shade.
  2. Track the sun across the season. A spot sunny in May can be shaded by a leafed-out tree or low autumn sun later. Watch where the shadows actually fall before committing.
  3. Add a grow light indoors. Growing tat soi 'yukina savoy' inside or on a windowsill? Run a strong full-spectrum LED 12–16 hours a day — windowsill light alone rarely crops well.
  4. Mulch and water to handle the heat. Full sun comes with heat stress; mulch and consistent watering prevent the scorch and bolting that sun gets blamed for.

Does tat soi 'yukina savoy' need a grow light?

For indoor or windowsill growing, tat soi 'yukina savoy' almost always needs a grow light to crop properly: a strong full-spectrum LED run 12–16 hours a day, positioned close. Light is the single biggest limiting factor for a sun crop grown inside — soil and water can be perfect and it will still fail in dim light.

The seasonal light shift (why winter changes everything)

Tat Soi 'Yukina Savoy' is a growing-season crop. Outdoors, plant it so its main growth lands in the long, high-sun months — light and warmth fall away fast from autumn. For year-round indoor growing you must replace the lost winter sun with a grow light on a timer; the natural window light from October to February is far too weak for cropping.

Light and watering are linked: a plant in weaker winter light photosynthesises and drinks far less, so the same routine that worked in summer can rot it. See how often to water tat soi 'yukina savoy' for the season-by-season schedule that pairs with this light plan.

Tat Soi 'Yukina Savoy' light requirements — frequently asked questions

How much light does tat soi 'yukina savoy' need?

Tat Soi 'Yukina Savoy' needs Outdoor full sun is ~5,000–10,000+ fc; far beyond anything a windowsill provides. Tens of thousands of lux in open sun — orders of magnitude more than typical indoor light. Full sun outdoors: an open spot that gets 6–8 hours of unobstructed direct sun, ideally including midday. Indoors or on a windowsill it needs the brightest south-facing position you have and usually still benefits from a grow light.

Can tat soi 'yukina savoy' survive in low light?

No, not really. Tat Soi 'Yukina Savoy' is a sun lover — in low light it etiolates: it stretches, pales, weakens and slows right down. It will not instantly die, but it steadily declines and never looks its best.

What are the signs tat soi 'yukina savoy' is getting too much light?

In extreme heat plus intense sun, leaf scorch or sunscald on exposed fruit — usually a heat/water-stress combination rather than light alone; mulch and steady watering fix most of it. Wilting in the fiercest afternoon sun that recovers by evening — tat soi 'yukina savoy' is photosynthesising hard, not over-lit; keep it watered. Bolting (premature flowering) in leafy crops is triggered more by heat and daylength than raw light intensity. Tucking tat soi 'yukina savoy' into a part-shade corner and expecting a full crop. Leafy growth tolerates some shade, but fruit, roots and flavour are paid for in hours of direct sun — short the light and you short the harvest.

What are the signs tat soi 'yukina savoy' is not getting enough light?

Tall, pale, leggy, floppy tat soi 'yukina savoy' reaching for the light, with thin stems that flop — classic shade etiolation. Poor flowering and a small, late, disappointing or non-existent harvest — the clearest sign it is under-lit. Lush dark leaves but few fruit; soft growth that pests and disease find easily. If you see this, move tat soi 'yukina savoy' closer to the light or add a grow light — and check our guide on leggy, stretched plants.

Does tat soi 'yukina savoy' need a grow light?

For indoor or windowsill growing, tat soi 'yukina savoy' almost always needs a grow light to crop properly: a strong full-spectrum LED run 12–16 hours a day, positioned close. Light is the single biggest limiting factor for a sun crop grown inside — soil and water can be perfect and it will still fail in dim light.

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