Solidify modifier not working

[Jeremy_Weed]

I am trying to apply the solidify modifier to this object I have that has also had the subdivision surface modifier applied to it and I get this:

What could cause this and how could I fix it? Thank you in advance!

[JohnMalcolm1970 (John Malcolm)]

Recalculate normals (shift+N) in Edit mode

[Jeremy_Weed]

thank you!