Normalize the plant
Listings are matched to a canonical cultivar and separated by stage: Tissue Culture, Acclimated, or Established. Ambiguous matches are quarantined for review.
MARKET METHODOLOGY
How Plant Market calculates prices.
The goal is to make the number useful without pretending rare plants trade like perfectly liquid stocks.
Balance the sources
We calculate a median inside each source first, then take the median across sources. That prevents a marketplace with hundreds of listings from overpowering every smaller source.
Separate wholesale
Wholesale/source-cost data is displayed independently and does not directly set the consumer market price.
Score confidence
Confidence reflects independent source count, observation volume, freshness, agreement between source medians, and confirmed-sale evidence. It is a data-quality score, not a forecast.
Build the index
Each tracked Tissue Culture market is rebased to 100 at the beginning of the displayed period. Plant Market then takes an equal-weighted average of those price relatives.
Keep history
Every accepted observation is retained. Historical charts are reconstructed from daily source-balanced medians instead of overwriting yesterday’s price.
RARE PLANT INDEX
Equal-weighted price relatives
Index(t) = 100 × average[ Priceᵢ(t) / Priceᵢ(start) ]This means a $300 plant and a $30 plant contribute equally to percentage movement. The index measures the direction of the tracked market, not the total dollar value of all plants.
What the index does not mean
Plant markets are fragmented and exact-plant quality matters. Variegation, grade, shipping, seller reputation, geography, and maturity can create legitimate price differences. Plant Market should be treated as a market reference—not an appraisal guarantee.