Around the map, i've planted a fair amount of seeds and watered them with different types of water, and sometimes instead of redeemable items/weapons, a grenade or a zombie, the seeds turn into different sorts of traps. I don't think this mechanic has been discussed enough, but how does the water affect the seeds? What coloured water bears fruit to what "plant trap"?

Is this a mechanic that was carried over from MORI? Have i missed their explanation in the EE
Guides?