How much will a bad semester or two damage my transfer chances?

I currently have about a 1.9 gpa. My first semester of college I got 3.0, but second semester I got 0.0 When I learned about parties. After that I returned to a middling semester of about a 2.0, after which I left that university to attend my local community college. I learned my lesson, got down to work, and pulled a 3.5 out last quarter. I think I can get at least that consistently.

My question is, how damaging will my bad semesters be to future transfer applications? I know I’m not exactly Harvard material, but I would like to get into somewhere halfway decent. How low must I set the bar? I expect somewhere like ASU would take me, I’m curious about UC Merced and other schools in that range. Should I even bother applying when the time comes, or is it a waste of money?

In my opinion formed from limited experiences, I think UC Merced might overlook poor grades in favor of improved grades and upward trend. I wouldnt be too optomistic about UCs past Merced, Santa Cruz and Riverside.

In general – and I am not providing university-specific opinions or information – grades of this sort will be a SIGNIFICANT transfer impediment.

well, 2/3 of your grades are bad. So, yes, it’ll damage your transfer chances significantly. Forget the UCs - they’ve become very competitive even for CA CCs and a GPA well above 3.0 is now expected. Merced will NOT take someone with a 1.9 GPA.
You need to stay at your CC until your GPA is above 2.5 (minimum to hope for a transfer) and preferably closer to 3. Maintain that semester GPA at 3.5 for a couple more semesters.
If you can bring your GPA to the 2.5-3 range, ASU will be okay, CSUs will be too outside of the most selective ones (like SDSU, CSULB, etc.)