You cannot splice GALACTIC STARSEED. You have to buy it or acquire it otherwise. This item belongs to terrain category. Planting GALACTIC STARSEED and kicking back is the right attitude. Breaking this block will give you 11 experience points. Digging mods will help you with this block. You get at least 1 seed back (maybe more!) from splicing GALACTIC STARSEED. Profiting with this might be questionable. Blockratio of GALACTIC STARSEED is a mystery. Maybe you can check the wiki for <a href="https://growtopia.fandom.com/wiki/Galactic_Starseed">galactic starseed</a>