When do you start fishing big ribbon tails? Water temp a major factor? Never really tried them much and would like to start.

i fish alot of grass lakes so when that grass really starts to mature and get thick i get out the 10 inch worms on heavy lead. usually about july

I like hot weather for the big worms. Late June, July and into fall. A big Culprit is one I've used for years.

Usually start first to middle of June. I like a frog post spawn when the fish are still shallow, as the water warms and the grass gets thick I start throwing a 10 or 12 inch worm.

Normally, only after water temp. hits 70, but I still throw them after the water cools below that temp. in the fall.

The small ones (Zoom UV Speed worm) come out as soon as the males are guarding.  It's a sure thing rigged weightless and jiggled down right on top of them. 

 

Later, when the water temps get over 80 degrees, a Berkley MaxScent Kingtail can sometimes be the only thing that will get a bite.