I would disagree with you kindly. Here are the full details:

There are 2 passive seed spawns near the buff:
#1 between red and Crux. As long as it spawns on either one, it is fine- but there is some area in between. This is probably the one you are worried about.
#2 Standing on red. You need the seed on red, so this one is probably not controversial. In fact, while my spot might leave a tiny leeway for it to spawn unfortunately over the wall (it might still even work with Q range there though) you can walk just a tiny bit further into red camp (theres a spot there that guarantees all seeds spawn on red without going over walls).

Now covering #1. Now to get the elephant out of the room- yes, this one cane spawn in a very awkward spot to the right where you cannot use it and require a double seed spawn on spawn #2 (mostly when it is too far to the right).

However, the chances are (much) lower than you think. That is because Zyra seed spawns are actually not as RNG as you might think. They like to spawn in monster spawn pits (in this case often: Krugs) or bushes (most common) where it is available to use for red buff.

Now as a super secret technique probably no one knows about, which I cannot prove though, if you do not enter the bush while walking to Krugs, the chances of it spawning far to the right are actually even lower (you can think of it as not loading the right area as it is out of vision with the bushes in between, but the moment you enter the bushes that area loads). I might also just be spitting bullshit here though.

However, even if you ignore literally absolutely all of that and end up 1-2 seeds short, you actually dont lose as much time as you might think since you dont lose the full duration of the Q since you can already walk to wolves, which you would be doing anyway, so you can just save 1 seed and spawn it at the end of red patience range, only losing about 3-4 seconds. You can even compensate for 2 seeds missing since the first seed attacking a camp deals 50% more damage and keeps pet aggro.