diff --git a/README.mdown b/README.mdown
index f8c8828..5084364 100644
--- a/README.mdown
+++ b/README.mdown
@@ -483,7 +483,7 @@ These endophytes do not protect our mushroom roots and will compete for resource
 
 Take-out containers are available at most grocery or box retailers.
 They must have black opaque bottoms with clear lids, usually made from polypropylene.
-You can tell if they are polypropylene if they are advertised as dishwasher and microwave safe.
+You can tell if they are polypropylene when they are advertised as dishwasher and microwave safe.
 Polypropylene products also carry a recycling #5 designation.
 
 0. Soak the coconut coir brick by following the packaging instructions for 12 hours.