Have a sudden problem in the backyard and garden with standing water and green slime. Need serious help.?

Question

Dug out garden by hand. mixed in probably 90% sand with original clay minus all the rocks. Looks like I developed a pond full of scum. Help! Cannot explain the scummy yuck on the new growing grass.

Answer 1

drainage problem. try a french drain

Answer 2

Yeah, that's what it sounds like you did.  

Don't water so much.  

Put in some drains.  French drains around the edges would probably work.  Or buried drain tiles or tubing.  

Don't know what to telly you about the slime.  If you get the place to dry out I'm sure it will go away.