diff --git a/scrape/README.md b/scrape/README.md
index 2dd1fd0..e1f371c 100644
--- a/scrape/README.md
+++ b/scrape/README.md
@@ -41,20 +41,26 @@ Every scraper is **idempotent** by default — re-running with the
 same arguments skips records already on disk. Use `--force` to
 re-fetch.
 
-## Scope: row crops only
+## Scope: corn / soybeans / wheat
 
-The corpus is scoped to **US row crops** — corn, soybeans, cotton,
-wheat, rice, sorghum/milo, barley, oats, rye, sunflowers, peanuts,
-sugar beets, dry/field beans, canola/rapeseed, and alfalfa. The
-EPA PPLS scraper enforces this by inspecting the `sites` array on
-each product's PPLS API response and dropping anything without a
-row-crop site (word-boundary match).
+The corpus is scoped to the three crops the consumer app focuses on:
+**corn (incl. maize, popcorn), soybeans, and wheat.** The EPA PPLS
+scraper enforces this by inspecting the `sites` array on each
+product's PPLS API response and dropping anything without a matching
+site (word-boundary match against `ROW_CROP_KEYWORDS`).
+
+Empirically (random N=100 sample): this narrow allowlist matches
+~16% of all PPLS products and only loses ~6% of the broader
+"all US row crops" hit set, because corn/soy/wheat dominate ag
+chemistry registrations — products registered for cotton/sorghum/
+rice/etc. are almost always *also* registered for one of corn,
+soy, or wheat.
 
 The Bayer scraper doesn't filter — its catalog is implicitly
-ag-focused, and dropping fungicide/insecticide/seed-treatment
-products there would lose row-crop-relevant chemistry. Add
-per-source filters as needed if other manufacturer sources cover
-non-ag products.
+ag-focused, and the catalog product names + descriptions don't
+expose enough crop metadata for a pre-API filter to be reliable.
+Add per-source filters as needed if other manufacturer sources
+turn up non-ag products.
 
 Override the EPA filter for a one-off broader pull:
 
diff --git a/scrape/sources/epa_ppls.py b/scrape/sources/epa_ppls.py
index 77af57f..39bfbe6 100644
--- a/scrape/sources/epa_ppls.py
+++ b/scrape/sources/epa_ppls.py
@@ -83,23 +83,17 @@ MAX_RETRIES = 4
 # "OATS" naively matches "SHIPS, BOATS, SHIPHOLDS"; bare "RICE" matches
 # "LICORICE"; bare "RYE" matches "FRYER".
 #
-# Scope = the major US row + small-grain + oilseed + sugar/fiber crops the
-# farmer-advisor consumer cares about. Alfalfa included as a common rotation
-# crop; sweet/seed corn included alongside field corn.
+# Scope = the three crops the farmer-advisor consumer focuses on: corn,
+# soybeans, and wheat. Sweet/seed/pop corn included alongside field corn.
+# Empirically (random N=100 sample, 2026-05-23): this narrow allowlist
+# matches ~16% of all PPLS products and only loses ~6% of the broader
+# "all US row crops" hit set, because corn/soy/wheat dominate ag chemistry
+# registrations — almost every product registered for e.g. cotton or
+# sorghum is co-registered for at least one of corn/soy/wheat.
 ROW_CROP_KEYWORDS = (
     "CORN", "MAIZE", "POPCORN",
     "SOYBEAN", "SOYBEANS",
-    "COTTON",
     "WHEAT",
-    "RICE",
-    "SORGHUM", "MILO",
-    "BARLEY", "OATS", "RYE",
-    "SUNFLOWER", "SUNFLOWERS",
-    "PEANUT", "PEANUTS",
-    "SUGAR BEET", "SUGAR BEETS",
-    "DRY BEAN", "DRY BEANS", "FIELD BEAN", "FIELD BEANS",
-    "CANOLA", "RAPESEED",
-    "ALFALFA",
 )
 _ROW_CROP_PATTERNS = tuple(
     re.compile(rf"\b{re.escape(kw)}\b", re.IGNORECASE)
diff --git a/sources.json b/sources.json
index 29d304d..b6f3f07 100644
--- a/sources.json
+++ b/sources.json
@@ -16,6 +16,6 @@
     "scraper": "scrape.sources.epa_ppls",
     "scraper_version": "0.1.0",
     "license_note": "US federal government — public domain (no ToS restriction)",
-    "scope_filter": "row-crop only — products with at least one site matching CORN, MAIZE, POPCORN, SOYBEAN(S), COTTON, WHEAT, RICE, SORGHUM, MILO, BARLEY, OATS, RYE, SUNFLOWER(S), PEANUT(S), SUGAR BEET(S), DRY/FIELD BEAN(S), CANOLA, RAPESEED, or ALFALFA (word-boundary match). Pass --no-row-crop-filter to scrape the full PPLS universe."
+    "scope_filter": "corn / soybean / wheat only — products with at least one site matching CORN, MAIZE, POPCORN, SOYBEAN(S), or WHEAT (word-boundary match). Hits ~16% of the PPLS universe in sampling. Pass --no-row-crop-filter to scrape the full PPLS universe."
   }
 ]