It is really easy to talk smack about PHP because as a language it is not the prettiest, best designed, or cleanest language out there. It often leads to some very gross code.
However, programmers write ugly code in every language and even in a much more beautiful language like Ruby, there are so many projects that end up with ugly codebases, poor performance, etc. that PHP by no means holds an exclusive ownership of terrible coding practices.
Writing high quality code in any language takes significant effort on an ongoing basis. Practices like TDD, code review, pairing, etc. can help, but only if they are applied with significant effort.
However, programmers write ugly code in every language and even in a much more beautiful language like Ruby, there are so many projects that end up with ugly codebases, poor performance, etc. that PHP by no means holds an exclusive ownership of terrible coding practices.
Writing high quality code in any language takes significant effort on an ongoing basis. Practices like TDD, code review, pairing, etc. can help, but only if they are applied with significant effort.