And now that Dartcraft 0.2.16 is out, it looks like time manipulation... kind of works? I tried it out in creative, spamming the time rod on the hyper setting advanced 9 seeds to the second stage pretty much instantly (and that on dirt), but then the effect stopped working, no matter how many more times I tried it. Nine seeds on end stone worked for four of them, which also got to the second stage right away, but the rest of them didn't react at all.
I forgot to test time torches though, but I bet the effect would be the same. Didn't have enough patience to try waiting to see if the seeds got stuck or if they would continue growing normally, either.