Advanced — agar + strain keeping
Agar work + strain isolation — keeping your own genetics
Isolate fast colonizers. Bank cultures. Dial in your own strains.
Total time
50 hrs
hands-on across the full cycle
Cost
$1850
all supplies sourced
Stages
5
step-by-step progression
Prerequisite: complete liquid-culture-and-grain-spawn before attempting this tier. Sterile-technique habits matter more than equipment at this level.
What you'll do
Once your sterile workflow is reliable enough that you're getting >90% clean colonizations, the next unlock is agar. Working on agar plates lets you isolate the fastest-growing mycelium from a multi-spore germination, save genetics in a culture library, and run side-by-side trials of strain performance. This is the level where commercial growers and serious hobbyists live. The investment is meaningful — a flow hood ($600-1,200), a stereo microscope, an agar pour station — but it pays back in reliable yields, novel strains, and the ability to take genetic snapshots of any wild mushroom you find. This tier assumes you've completed Intermediate and are comfortable with sterile technique.
Stages
- 1
Build or buy a flow hood
Day 0 of cycle
A laminar flow hood blows HEPA-filtered air toward you, creating a sterile field where your hands work. DIY builds with a 2x4 ft HEPA filter and a squirrel-cage blower run $300-500; commercial benchtop units run $800-1,500. A flow hood transforms agar work from frustrating to routine — contamination rates drop from 30% in a SAB to <2% under proper laminar flow.
Supplies for this stage
Pitfalls
- •Cheap blowers leak unfiltered air — get a sealed squirrel cage rated to push air through 2 inches of static pressure
- •Velocity must be 90-100 fpm at the filter face; too low lets contaminants creep in, too high turbulent
Success signal
Smoke test: smoke pulled cleanly off filter face into the room with no eddies
- 2
Pour agar plates
Day 2 of cycle
Standard recipe: MEA (malt extract agar) — 20g malt extract + 20g agar + 1L water. Boil to dissolve. Pressure cook in flask 30 minutes at 15 PSI. Pour 15-20 mL per Petri dish in flow hood. Cool to room temp. Stack and refrigerate up to 30 days.
Supplies for this stage
Pitfalls
- •Pouring too hot causes condensation that drips onto the agar surface; let flask sit 5 min off heat first
- •Pouring too cool leaves lumps; if it's setting, microwave 30 sec to remelt
Success signal
Smooth, level plates, no condensation, no contamination after 5 days incubation
- 3
Multi-spore germination + isolation
Day 5 of cycle
Take a spore print from a healthy mushroom. Suspend a piece in sterile water. Streak across an agar plate using a sterilized loop. Within 7-10 days, you'll see dozens of distinct mycelial sectors radiating from the streak. Isolate the fastest, healthiest, most uniform sector using a sterile scalpel — transfer a small triangle of agar with mycelium to a fresh plate. Repeat 2-3 times to lock in genetics.
Supplies for this stage
Pitfalls
- •Choosing the fluffiest sector is wrong — fluffy mycelium often fruits poorly. Choose dense, fast-growing, rhizomorphic patterns
- •Don't transfer near the edge of a sector where another genetic line might be encroaching
Success signal
Homogeneous plate of single-isolate mycelium, growing radially uniform
- 4
Strain bank + cold storage
Day 30 of cycle
Once you have isolates worth keeping, make a culture bank. Slants (test tubes with sloped agar) keep cultures viable for 6-12 months refrigerated. Liquid culture syringes from a known-good plate keep 3-6 months. For long-term archival, distilled-water storage (cubes of mycelium-on-agar in sterile water at 4°C) keeps cultures viable 5-10 years.
Supplies for this stage
Pitfalls
- •Unlabeled cultures = useless cultures. Date, species, isolate-number, source
- •One backup is no backup — keep 2 slants and 1 distilled-water vial per isolate
Success signal
Labeled, dated culture library in fridge, 2 backups per isolate
- 5
Side-by-side strain trials
Day 45 of cycle
Run 2-3 isolates against each other through grain → bulk → fruit using identical inputs. Track: colonization speed, contamination rate, time to pin, total yield, fruit body morphology, taste. After 2-3 trials, you have data to keep the winner and discard the rest. This is how commercial cultivators differentiate.
Supplies for this stage
Pitfalls
- •Comparing across different substrate batches confounds the result; run trials with substrate from the same hydration
- •Single-trial conclusions are noise; require 2-3 cycles of consistent winners before retiring an isolate
Success signal
Quantitative grow log showing consistent strain performance differences
Expected outcome
Curated culture library + reproducible 2x+ yield improvements over generic LC strains
Recommended species
- Any species — agar work is universal
- Best for novel/wild strains: Pleurotus, Hericium, Ganoderma