diff --git a/src/soil/semantics.py b/src/soil/semantics.py
index 9908084f3911b2d27ac9ab4e180379aaa4f5a431..12fc7005bac799033c3f4816b9b1400511f62e95 100644
--- a/src/soil/semantics.py
+++ b/src/soil/semantics.py
@@ -43,7 +43,7 @@ class Namespaces(object):
     quantitykind = rdflib.Namespace('http://qudt.org/vocab/quantitykind/')
     qudt = rdflib.Namespace('http://qudt.org/schema/qudt/')
     rdf = rdflib.namespace.RDF
-    schema = rdflib.Namespace('https://schema.org/')
+    schema = rdflib.Namespace('http://schema.org/')
     si = rdflib.Namespace('https://ptb.de/si/')
     soil = rdflib.Namespace('https://purl.org/fair-sensor-services/soil#')
     sosa = rdflib.namespace.SOSA