Now, let me see if I got this right - you removed the irrigation system and now your plants are droopy?
Would this not suggest they are thirsty?
That would be my guess.
Cheers,......
Organoman.
P.S. - make sure to remove the basil come flowering time, it will cause your buds to smell and taste like basil. I know they are a good companion plant, and I also know about the way basil will contaminate your flowers, through first hand experience!