פּירוש אויף דברים 33:14

וממגד תבואת שמש AND BY THE PRECIOUS FRUITS BROUGHT FORTH BY THE SUN — for this land lay exposed to the sun and it therefore produced sweet fruit (Sifrei Devarim 353:3).

וממגד גרש ירחים, “and from the precious things due to the moons.” The fruit of the trees emanate from the earth, and the trees start growing at the beginning of the month. On each new moon a different category of fruit tree commences the cycle of growing and subsequently ripening. Our author quotes four examples of this as an illustration.

the sun’s produce the products of field and vineyard are dependent on the sun.

גרש ירחים [AND BY] THE PRECIOUS THINGS PUT THINGS FORTH BY THE MOON — there are some fruits which the moon brings to maturity, these are cucumbers and melons (Sifrei Devarim 353:3). — Another explanation of גרש ירחים: this refers to fruits which the earth puts out and produces from month to month (cf. Onkelos).