Tried to find the noises of everything by placing several of just their seed on the board
purple-blue swirly seed - flute sounding noise? not too sure what it is
cactus seed - string instrument, most hearable sound in normal planting. violin?
minecraft emerald shaped but yellow tree seed - seems to also be a violin but the noise is more consistent and shifts less.
sunflower seed - underlying tension bass
literally just a green circle seed tree - slight tambourine or bells ringing
corn seed - makes the noise of corn. I mean. Well I don't think it makes a noise at all
four green squares looks like tree seed - absolutely nothing
leaf seed it's green and it has leaves - it makes noises when it grows. yknow, like everything else in the game
pink twisty seed - silence
pink flower looking seed - oh finally something that makes noise. drums hitting thing. instrument you hit
ones that don't make noise are possibly because they do something unnoticeable on their own like shift tempo of certain plants (not testing that) or just because I can't hear them.