."I" .. merged the threads. They were both on the same subject, and both similar dates.
You wanna' talk about seing the same same redundant questions?? .. wait untill you've been here as long as a few of the real vetrans have. How many times over the past 5+ years, I've read the question.. "How can I make my plants grow?"... or "What is causing thes yellow spots?"...
The search feature is a newbies best friend here, without a doubt. There are literally thousands of questions answered tens of thousands of times.
There us nothing wrong with bringing up old threads, 'if' they are relevant and answer a present question. There is a great deal of knowledge and experience archived here. However, .. replying/responding to a question asked 6 months, or a year or more ago, probably isn't going to do that guy any good. If it is relevant to a present question, problem you're having, IMO, it's perfectly acceptable, maybe even recommended to continue the thread.
THAT is the difference in bringing up old threads.