Black Rainbow Auto by Seedstockers

Black Rainbow Auto delivers the kind of bag appeal usually reserved for photoperiod dessert strains. Expect frosty, rock-hard buds, fruity modern terpenes with a Kush and fuel undertone, and THC in the 20–26% range, all in an indica-leaning autoflower that runs about 11 weeks from seed to harvest.

This Seedstockers Superior release finished second in the auto category at The North Grow Cup, an award the breeder lists for the strain. Like every autoflower, it blooms with age rather than light change, so an 18/6 or 20/4 schedule can run from germination to the chop.

The plants stay compact and vigorous, with strong lateral branches and tight, heavy flowers. Indoors, expect about 400–450 g/m² (1.31–1.47 oz/ft²); outdoors, each plant typically gives 100–170 g/plant (3.5–6.0 oz/plant).

Lineage: Watermelon Zkittlez, Bacio Rainbow and Apollo Black Cherry

Black Rainbow is a three-way cross. Seedstockers first combined Watermelon Zkittlez with Bacio Rainbow, two modern American dessert lines known for sweet fruit and dense resin, then crossed that hybrid with its own Apollo Black Cherry Auto to bring in the autoflowering trait and extra dark-fruit depth.

That pairing delivers sweet, fruity complexity, compact and dense flower production, high resin levels and a relaxing indica-leaning potency, wrapped in a reliable, fast-finishing autoflower.

Aroma, Flavor and Effect

The first sniff is fruity and sweet, with dried orange peel and ripe berries up front. Underneath, earthy spice and a classic hash note give the bouquet a darker, more serious side.

On the palate, sweet berries and dark fruit lead, joined by citrus peel and a tropical touch. Diesel and spicy layers come through mid-draw, and the exhale finishes woody and Kush-like. The result is a profile that feels modern and old-school at the same time.

The effect is layered. It begins with a noticeable cerebral shift and sharper sensory perception, colors and music feeling a little more vivid, before gradually settling into calm, dreamy body relaxation. It is not a full knockout, but it clearly leans to the chill side, which makes it a fit for late afternoons and evenings.

Growing Black Rainbow Auto Indoors and Outdoors

Plant directly into the final 11–20 L (2.9–5.3 gal) container to avoid transplant shock, and run 18/6 or 20/4 indoors. Keep the substrate pH around 6.0–7.0. Skip topping and harsh pruning; this auto rewards a smooth, uninterrupted cycle far more than aggressive training. Gentle LST is enough to open the canopy.

The buds grow very tight, so humidity management matters late in flower. Good airflow and a dehumidifier in the final weeks keep the colas clean. Small sugar leaves make trimming quicker, and the flowers range from light green to darker shades with bright orange pistils under a sugary coat of resin.

Outdoors, the strain performs well in warm and temperate climates with strong sun. Watch the weather in late flower: if conditions turn humid, inspect the dense buds regularly for mold and harvest promptly when ready.

Black Rainbow Auto Characteristics

Strain type	Autoflowering feminized
Genetics	(Watermelon Zkittlez x Bacio Rainbow) x Apollo Black Cherry Auto
Indica/Sativa	Indica dominant
THC	20–26%
Effect	Relaxing, cerebral, dreamy, slightly psychedelic
Flavor	Berries, dark fruit, citrus peel, tropical, diesel, woody Kush
Aroma	Fruity, dried orange peel, berry, earthy spice, hash
Indoor yield	400–450 g/m² (1.31–1.47 oz/ft²)
Outdoor yield	100–170 g/plant (3.5–6.0 oz/plant)
Seed to harvest	About 11 weeks
Height	Compact
Difficulty	Easy to intermediate
Best cultivation technique	Gentle LST, no topping, direct sowing in final pot

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