Rainbows

Rainbows Cannabis Seeds by BSF Seeds

Rainbows is a feminised photoperiod cannabis seed from BSF Seeds that delivers some of the most visually striking buds you'll ever grow — swollen calyxes painted in shades of blue, pink, and purple, coated in a thick layer of frosty trichomes. Built on a double Zkittlez cross with Grape Ape and Grapefruit genetics, this indica-dominant strain produces a fruit cocktail flavour profile that matches its jaw-dropping bag appeal. Four seeds per pack, and every one is feminised.

Why Rainbows Cannabis Seeds Deserve a Spot in Your Garden

We've seen a lot of colourful strains come through, and most of them lose their pigment during the cure. Rainbows doesn't. The blue, pink, and purple hues carry through from the living plant right into the jar, sitting under a crisp blanket of trichomes that catches the light like sugar on fruit. If bag appeal matters to you — and let's be honest, it should — this is one of the best-looking strains BSF Seeds has put out.

But looks alone don't earn a permanent spot in anyone's rotation. The flavour is where Rainbows really earns its keep. The double Zkittlez backbone brings that unmistakable candy sweetness, while Grape Ape contributes a deep, grapey undertone and classic Grapefruit adds a tart, sweet citrus edge. Together they create something that genuinely tastes like a fruit cocktail — not a vague "fruity" note you have to squint to find, but a proper layered flavour that lingers on the exhale. An unknown third parent rounds out the genetics and adds its own subtle twist to the terpene profile.

The honest limitation? BSF Seeds doesn't publish exact THC percentages for Rainbows, so you're going in without a hard number. From what we've seen with double Zkittlez crosses, expect a solid indica effect — but if you need precise lab-tested potency data before you commit, this one asks you to trust the genetics rather than a spec sheet. Compared to something like BSF Seeds' other indica lines or a straightforward Zkittlez feminised seed, Rainbows trades a known THC figure for genuinely exceptional flavour and visual appeal.

Growing Rainbows Seeds: What to Expect

Rainbows is an easy-to-grow indica that stays fairly short, which makes it one of the best feminised cannabis seeds for indoor growers working with limited vertical space. It performs equally well outdoors or in a greenhouse, but that compact stature is a real advantage if you're running a tent of 80x80cm or smaller.

One thing to plan around: Rainbows can double in size during the first few weeks of bloom. That stretch is typical for indica-dominant photoperiods, but it catches people off guard if they flip to 12/12 too late. The rule of thumb from BSF Seeds is to switch your lighting schedule when plants reach about half their target height. If you misjudge it, don't panic — Rainbows recovers quickly from both high-stress and low-stress training. Topping, supercropping, or a simple LST tie-down will bring the canopy back under control and actually increase your final yield.

This is a hungry plant. Rainbows yields better when well-fed, so don't be shy with nutrients during the bloom phase. It responds well to a full feeding schedule and shows deficiencies quickly if you underfeed — yellowing fan leaves in week 4 of flower is the usual sign. Bump up your bloom nutrients and she'll bounce back within days.

Flowering takes approximately 8 weeks. BSF Seeds recommends watching the pistils: harvest as soon as they start changing colour for a brighter, more uplifting effect, or let the plant run another week or two for bigger yields and a deeper physical stone. A few days of complete darkness right before chop can help the resin thicken and fill with terpenes — it's a trick that works particularly well on trichome-heavy strains like this one.

Flavour and Aroma Profile of Rainbows

The terpene profile on Rainbows reads like a fruit bowl. Sweet grapefruit from the Grapefruit grandparent hits first — bright, citrusy, almost juicy on the inhale. Then the Grape Ape side rolls in with a darker, grapey sweetness that sits underneath like jam on toast. The double Zkittlez cross ties it all together with that signature candy-sweet finish that Zkittlez is famous for.

What makes it interesting is the unknown third parent in the lineage. BSF Seeds hasn't disclosed what it is, but it adds a subtle complexity that stops the flavour from being a straightforward fruit punch. There's a slightly funky, almost fermented quality in the background — like overripe stone fruit — that gives the smoke more depth than you'd expect from a strain that looks this pretty. During the cure, the grapefruit notes intensify. We'd recommend curing for at least 3 weeks in glass jars to let the full terpene profile develop.

Rainbows Seeds: Indoor vs Outdoor Growing

Indoors, you have more control over the temperature drop that brings out those blue and purple pigments. Lowering your night-time temperature to around 15-18°C during the last 2 weeks of flower can dramatically intensify the colours. Outdoors, autumn does this naturally in most European climates — but if you're growing in a warm Mediterranean spot, the colours may be less vivid. The trichome production and flavour won't suffer either way; it's purely cosmetic.

How to Grow Rainbows Cannabis Seeds

1. Germinate your feminised Rainbows seeds using the paper towel method or directly in a starter plug. Keep temperatures between 22-26°C and maintain high humidity (around 70%). Taproots typically emerge within 24-72 hours.
2. Transplant seedlings into their growing medium once the taproot is 1-2cm long. Rainbows isn't fussy about medium — soil, coco, or hydro all work. For the best flavour expression, many growers prefer a living organic soil.
3. Vegetate under 18/6 or 20/4 lighting. Keep in mind that Rainbows will roughly double in height after the flip, so calculate your target size accordingly. If you want a finished plant at 80cm, flip at 40cm.
4. Apply training during veg if you want to maximise yield. Top once above the 4th or 5th node for a bushier canopy. LST works brilliantly too — Rainbows recovers quickly from both methods and responds with more bud sites.
5. Switch to 12/12 lighting to trigger flowering. Increase bloom nutrients gradually over the first 2 weeks of flower. Rainbows is a hungry indica — don't hold back on phosphorus and potassium during this phase.
6. Monitor pistil colour from week 7 onwards. Harvest when pistils begin to change for a brighter effect, or wait an extra 1-2 weeks for larger yields and heavier physical effects. Use a jeweller's loupe to check trichome colour for precision.
7. Optional: give the plants 48-72 hours of complete darkness before harvest. This can encourage a final push of resin production and help terpenes concentrate in the trichome heads.
8. Dry in a dark room at 18-20°C and 55-60% humidity for 7-10 days, then cure in sealed glass jars for a minimum of 3 weeks. The colours hold through the cure — open the jars daily for the first week to release excess moisture.