Something looks very off about those strawberry plants. I think because you've made them tight little individual plants (they're a groundcover in real life) and you made the berries huge like tomatoes.
They're are others that look weird and botanically implausible, but they don't exist in real life so I don't know how they're actually supposed to work.
Regarding seeds, I somewhat disagree with Manveru. In real life, just about anyone who gardens can tell most seeds apart readily at least to the level of genus, and someone who has specific experience can tell apart similar seeds of closely related species such as mustard and cabbage. Furthermore, there's really no reason that they couldn't all be depicted to look like seeds while still looking distinct. But taking into account what you've come up with to represent seeds, and the fact that time spent here isn't spent elsewhere, I'm gonna say don't bother. Just make a few different seed sprites for broad groups of seeds and make special ones for any with especially unique seeds.
Regarding intermediate growth sprites, I don't think you need to commit to the same number for everything. For commonly grown plants, your five stages make sense. For all other plants, even one "growing" stage would be a very good amount.
Also regarding the example, uh, that's not how wheat grows. It might be a good idea to consult with people who are generally knowledgeable for some of these sprites, such as a farmer or an older person in general. Although perhaps it can be said that that's what this thread is for. In the case of wheat, it stays about the color you have it in the second stage until it reaches its final stage and becomes ready to harvest, turning yellow means the plant has died and it doesn't keep growing after it dies. It also doesn't grow seeds straight out of the ground, first it grows in a purely vegetative form (looking like grass, because that's what it is) and then after reaching its full height (or nearly so) it "flowers" (though grass flowers don't look very floral) and then the flowers grow into seeds. You could probably do the first three as just a grass sprite offset different amounts like what you've done for the ripe sprite. On the plus side, you can use the whole sprite set for similar looking grains like barley and rye, and the first part before the flowering and seeding should be shareable among other more distantly related grains like oats and rice.
Plants aren't even visible until they are ready to harvest or recognised in the T inspection screen other than seeds, i agree to disagree with the creeping in of a feature that won't be represented in the vanilla game in any capacity that simply makes more work for yourselves. How would this convert to steam-versions ascii alternative with no mechanical detail to base it on?
I'm not sure I understand the meaning of your last sentence. Surely the ASCII version would simply have the ability to show this while in actuality retaining current visuals?