Génesis 1:11 Comentario: Rashi, Chizkuni, Rashbam & Sforno

תדשא הארץ דשא עשב THE EARTH SHALL SPROUT FORTH SPROUTS, HERB — דשא does not mean the same as עשב nor does עשב mean the same as דשא so that it is not a correct expression in Biblical Hebrew to say תעשיב הארץ, for the species of דשא are all different, each by itself being called this or that עשב, and it would not be linguistically correct for a speaker to say this or that דשא, for by דשא is meant that which forms the covering of the ground when it is filled with herbage.

תדשא הארץ, “let the earth sprout vegetation;” at this point the Torah begins with its report of G-d’s creative activity on the third “day”. The major result was that the surface of the earth became covered with different categories of vegetation including trees, in anticipation of G-d’s placing the luminaries in the sky on the fourth day. A different exegesis: the waters had already completed the process of contracting on the second day as part of that day’s activity, aided by the רקיע, horizon/atmosphere blowing itself up on the second day; for if the (upper) waters had not contracted, how could the earth beneath have become visible and already be covered with vegetation including trees?.

דשא, every kind of herb collectively is known as דשא whereas every individual type of herb is known as עשב.