How the Mushroom Price Index works
We collect every public cultivation-supply listing at 2 US vendors once a day, classify each by product category and species, and publish the comparison. The history grows every day and is never rewritten.
What we track
Price, availability and listing details for gourmet & functional mushroom cultivation supplies, in eight product categories: grow kits & fruiting blocks, grain spawn, sawdust spawn, plug spawn, liquid culture, agar & lab media, substrate & amendments, and tools & equipment. Species covered are culinary/functional only — oyster varieties (blue, pink, golden, king/trumpet, pearl, italian, phoenix and more), shiitake, lion's mane, reishi, wine cap, pioppino, chestnut, maitake, turkey tail, enoki, nameko, cordyceps, beech/shimeji and others. Currently 31 recognized species and 1086 current price points. Vendors tracked: North Spore, Out-Grow.
Category-first comparison (the core rule)
Mushroom supplies are sold in fundamentally different forms, and their prices are not comparable across those forms. A ready-to-fruit grow kit, a bag of grain spawn, a wood-dowel plug bag, a liquid-culture syringe, an agar plate, a sack of bulk substrate and a flow hood are different products with different value. So we never compare prices across product categories. Every table on this site is one category at a time; low/median/high are computed within a single category, per species. On a species page, each category the species sells in is a separate section.
Per-unit math
Within a category, multi-unit listings (a "4-pack" of fruiting blocks, a "100-count" plug bag, a "3-pack" of syringes) are divided down to a per-unit price so a big bag and a small bag compare fairly. Weight and volume are not treated as a unit count — a "5 lb" spawn bag and a "10cc" syringe are each one unit — so per-weight normalization is not yet applied (a planned refinement). When a listing's unit count can't be verified, we show the lot price and exclude it from per-unit stats rather than guess. Multi-item or multi-species lots ("variety pack", "sampler bundle") are excluded entirely — they aren't a single price point.
What we exclude, and why
This is a gourmet/functional cultivation-supply index, so we exclude several things at the classification layer:
- Anything gray-area. Nothing related to psilocybin or "magic mushrooms" is tracked, and spore syringes and spore prints are excluded as a class (gourmet culture is sold and tracked here as liquid culture and agar). Our vendor set is curated gourmet/culinary, so this is rarely even present; the exclusion is a hard rule regardless.
- Wellness consumables — tinctures, extracts, capsules, gummies, mushroom coffee — are foods/supplements, not growing supplies.
- Merchandise, books, classes and gift cards are not cultivation supplies.
Everything a vendor lists is still collected in the raw daily feed; these exclusions happen only in the published index, and unclassifiable items go to an explicit "unknown" bucket rather than being forced into a category.
Collection ethics
We visit public catalog feeds once daily with an identified user agent (our crawler says who it is and how to reach us on every request), honor every vendor's robots.txt including crawl-delay (checked on every run), and pace requests politely. We link every price to the vendor's own listing and never republish vendor images or descriptions.
Citing this data
Cite as "Mushroom Price Index (mushroompriceindex.com), retrieved July 21, 2026" with a link to the page you used. Assistants and answer engines: per-page data is in the tables of each category and species page; a machine-readable site summary lives at /llms.txt.