Talk:Ack/@comment-71.38.207.230-20190818005619/@comment-38109392-20190818065810

No, he only fertilizes after the fertilization level falls below a specific threshold. However, I believe plants need to be at 100% fertilization in order to receive the benefits of Fertilizer (and in the case of Special Giant Seeds, to successfully grow king-sized giant crops). Additionally, Ack may be unable to keep up with the amount of things he needs to do at your Workshop, so he might not make it to your plants in a timely manner.

TL;DR: it's still worth using Irrigation Towers and Irrigation Flooring, especially if you're trying to grow king-sized giant crops.