diff --git a/src/farm/farm.jl b/src/farm/farm.jl
index 3bc3109e4efc086672a26681f147c3deb78065ce..c60cb93db7b39d423f388131bdd9a3f5ececa103 100644
--- a/src/farm/farm.jl
+++ b/src/farm/farm.jl
@@ -70,7 +70,7 @@ function stepagent!(farmer::BasicFarmer, model::SimulationModel)
                     @warn "minsowdate and/or maxsowdate is `missing` for crop \"$(ctype.name)\", not assigning sowdates"
                 end
             end
-        elseif cropname(field) == "no growth" && model.date == farmer.sowdates[f]
+        elseif cropname(field) == "no growth" && haskey(farmer.sowdates, f) && model.date == farmer.sowdates[f]
             # if a field has been harvested, check if the next crop can be sown
             @sow(farmer.croprotations[f][1])
         end