Not everyone reading this list is in the northern hemisphere, dear American friends. No hayfever problems in Oz at the moment!
As a long term sufferer of all allergens grassy, gliding is about the silliest place one can find oneself during summer.
I live about 3 hours drive from our club and have benefitted greatly from injesting LOCAL honey (from around the area of the club) all year before flying season.

Some wit told me it worked, so I tried and it did, simple.
Another wit told me it doesnt work so I ignored him, happy in the knowledge that most of the world believes in a god of some sort, without any real indication that there is one, and that works for them.

Gravity is my god, honey reduces hayfever.

It will take you at least 6 months of winter to prove it for yourself but honestly, it helps me.

Bagger