B+ Growing Guide: Timeline & Conditions

A healthy flush of B+ Psilocybe cubensis — broad, caramel-to-golden-brown caps on sturdy stems in a monotub

B+ is the strain most people should start with, and the one that quietly teaches the worst habits — because it forgives nearly everything a beginner does wrong, right up until the grow where it doesn’t. It carries the widest temperature tolerance of any variety in the Spores Lab catalog, which is exactly why it’s the right first grow for a Canadian home without dedicated climate control. This guide covers what makes B+ so forgiving, the full timeline stage by stage, the conditions it wants at each phase, and the trap that catches people who mistake “forgiving” for “foolproof.”

Beginner note. If this is your first grow, B+ and Golden Teacher are the two correct starting points. B+ edges ahead if your space runs cold or swings in temperature — a basement, a garage shelf, an unheated spare room. Start from liquid culture for the fastest, most predictable colonization.

What Makes B+ Different?

B+ behaves differently from most cubensis varieties in a few important ways — nearly all of them in the grower’s favour:

Temperature tolerance	The widest in the catalog — B+ performs acceptably from roughly 20–28 °C, where fussier strains stall or sulk. This is the single reason it’s the top pick for Canadian home growing without climate control.
Colonization speed	Fast and vigorous — comparable to Golden Teacher, not a slow strain. Healthy B+ mycelium is bright white and ropy, and it moves.
Fruiting	Reliable and generous. B+ pins readily and produces multiple flushes of large, meaty fruits with broad caramel-coloured caps.
Forgiveness	Highly tolerant of the mistakes beginners actually make — temperature swings, a humidity dip, imperfect fresh air exchange. Forgiveness is its defining trait, and its one hidden risk.

Starting Material: Spores or Liquid Culture for B+?

Unlike Penis Envy, B+ drops spores readily — the veil tears the way a cubensis veil should, so spore syringes made from B+ prints work. That means spores aren’t your only route here; liquid culture is simply the faster, more predictable one.

A spore syringe is a fresh genetic cross every time — a lottery of slightly different offspring. A liquid culture is one verified, vigorous specimen, already growing, so it skips the germination stage and your mycelium hits the grain running. If you want the same B+ every run, and days off the front of the timeline, start from culture. Spores Lab’s B+ liquid culture is cloned from a verified specimen and prepared fresh to order.

Step-by-Step: Growing B+

01	Inoculate grain jars with B+ liquid culture. Use 2–3 cc of LC per quart jar. Flame-sterilise your needle, wipe the injection port, and inject slowly. Work in a still air box or flow hood. See the liquid culture syringe guide for technique.
02	Colonization — B+ moves fast. Expect 10–18 days for full grain colonization at 24–27 °C. Shake once at ~30% colonization to distribute. Healthy B+ mycelium is bright white and rhizomorphic.
03	Prepare bulk substrate. A coco coir / vermiculite (CVG) mix at field capacity is the standard choice — see how to prepare CVG. B+ isn’t fussy about substrate, which is part of its appeal.
04	Spawn to bulk. When grain is fully colonized (100% white, firm), mix with bulk at a 1:2 to 1:4 grain-to-substrate ratio. Pack into your fruiting container.
05	Colonize the bulk. Seal and let it run at room temperature for 7–14 days, until the surface is fully white. B+ colonizes bulk quickly and evenly.
06	Initiate fruiting. Introduce fruiting conditions: fresh air exchange 2–3× daily, humidity 90–95%, temperature 21–24 °C, indirect light ~12 hours/day. B+ typically pins within 5–10 days.
07	Harvest. Pick just as the veil beneath the cap begins to tear — peak maturity, before spore drop. Twist and pull gently to avoid disturbing neighbouring pins, then rehydrate for the next flush.

How Long Does B+ Take to Grow?

B+ sits at the fast, forgiving end of the Psilocybe cubensis range. Expect 6 to 8 weeks from inoculation to first harvest under reasonable conditions — comparable to Golden Teacher, and meaningfully quicker than a slow strain like Penis Envy, which runs 8 to 12.

More useful than the headline number is how stable that timeline is. Because B+ tolerates a wide temperature band, its schedule holds up even when your conditions aren’t perfect — the grow that would stall a fussier strain at 20 °C keeps ticking along with B+. That predictability, not raw speed, is what makes it the reliable first grow.

The timeline, stage by stage

Stage	B+	Conditions that drive it
Liquid culture to colonized grain	10–18 days	24–27 °C, dark, no FAE needed
Grain to fully colonized bulk	7–14 days	24–27 °C, high humidity, minimal FAE
Bulk to first pins	5–10 days	Drop to 21–24 °C, 90–95% RH, FAE on
Pins to harvest	5–9 days	21–24 °C, 85–92% RH, steady FAE
Between flushes	7–14 days	Rehydrate, return to fruiting conditions

Ranges, not guarantees. Your grain hydration, spawn ratio, and how steadily you hold temperature will move these numbers more than the strain does — B+ just tolerates your imperfections better than most.

Why B+ is so forgiving

The trait that defines B+ is a broad environmental tolerance. Its mycelium is vigorous and robust, it out-competes contaminants readily, and it keeps colonizing across a temperature range that would slow or stall pickier genetics. A cold snap that drops your grow room to 20 °C is a shrug for B+ where it might cost a Penis Envy grower two weeks.

That resilience is genuine, and it’s why B+ earns its beginner reputation. But it’s a margin, not immunity — and the margin is exactly what gets spent without anyone noticing.

[IMAGE 2 — SVG infographic, provided separately: b-plus-temperature-tolerance.svg] Alt text: B+ tolerates a wider growing temperature range (about 20–28 °C) than fussier Psilocybe cubensis strains, making it suited to Canadian homes without climate control.

The stage where people get complacent

With Penis Envy, beginners give up too early. With B+, the opposite: they get complacent. B+ survives the single mistake that would kill a harder strain — a warm week, a skipped fanning, a substrate a little too dry — so growers quietly stop doing the fundamentals, and the grow still works. Until the run where two or three of those mistakes land at once, and there’s no margin left to absorb them.

The fix is to treat B+’s forgiveness as a safety net you don’t lean on: hold the fundamentals as if you were growing a fussy strain, and B+ will reward you with faster, cleaner, larger grows rather than merely surviving ones.

One specific trap worth calling out, because it’s the most common “my B+ stalled” message: a room thermometer is not a substrate thermometer. B+ tolerates a cold room, but a tub sitting on a 16 °C basement floor can be genuinely too cold inside even when the wall reads 21 °C. B+’s tolerance is wide, not infinite.

Environmental Parameters

Colonization temp	24–27 °C (tolerates ~20–28 °C — the widest band of any catalog strain)
Fruiting temp	21–24 °C
Fruiting humidity	90–95%
Fresh air exchange	2–3× daily minimum
Light	Indirect, ~12 hours/day
Expected colonization	10–18 days grain, 7–14 days bulk
Expected first pins	5–10 days after fruiting initiation

Start your B+ grow with our fresh LC. Clone-true B+ liquid culture, prepared to order. Ships across Canada. Shop B+ Liquid Culture →

Frequently Asked Questions on the B+ Growing Guide

How long does a B+ grow take start to finish? From inoculation to first harvest, expect 6–8 weeks under reasonable conditions — the fast end of Psilocybe cubensis, comparable to Golden Teacher and quicker than Penis Envy. The timeline also holds up better than most when conditions aren’t perfect.

What temperature does B+ need? B+ has the widest temperature tolerance of any strain in the catalog. Colonization is best at 24–27 °C, and it fruits at 21–24 °C, but it performs acceptably across roughly 20–28 °C — which is why it’s the go-to for Canadian homes without dedicated climate control.

Is B+ good for beginners? Yes — it’s one of the two best first grows alongside Golden Teacher, and the better pick if your space runs cold or swings in temperature. Just don’t let its forgiveness talk you out of clean technique; that’s the one way beginners come unstuck with it.

Spores or liquid culture for B+? Both work — unlike Penis Envy, B+ drops spores readily. Liquid culture is the faster, more predictable route: one verified specimen, already growing, with the germination stage removed and days off the front of the timeline.

Why is B+ recommended for growing in Canada? Its temperature tolerance. Canadian homes swing cold, especially basements and unheated rooms through the colder months, and B+ keeps colonizing and fruiting across a band that would stall fussier strains — so you can grow it without buying climate-control gear.

Related posts to link internally: - Golden Teacher Growing Guide: Timeline & Conditions — the other top first-grow - Penis Envy Growing Guide for Beginners — the demanding end of the range, for later - Growing Environment: Optimising Conditions for Mushroom Growth — the conditions behind every strain’s numbers - Mushroom Genetics & Strains — choosing a strain and why genetics matter - Best Strains for Beginners — how B+ compares across the beginner field - How to Use a Liquid Culture Syringe — technique for step 01

Spores Lab supplies Psilocybe cubensis spores and cultures for microscopy and taxonomic research only. In Canada, possessing psilocybin spores for research is legal because the spores contain no psilocybin; cultivation of psilocybin-containing mushrooms is illegal under the Controlled Drugs and Substances Act, and cultivation laws vary by jurisdiction. Customers are responsible for compliance with the laws that apply to them.