(Mishnah): They said a general rule about Ma'asros - Anything that is food, guarded and grows in the ground is obligated in Ma'asros.

They said a further rule - Anything that begins as food and ends as food, even if it's normally left (in the ground) to grow further, whether he picked it earlier or later, it is obligated. And anything that does not begin as food but ends as food, it is only obligated when it actually becomes food.

(Gemara): The Mishnah taught - They said a general rule about Ma'asros etc. The pasuk states (Devarim 14:22), "You shall tithe (all of your seed crop that the field produces, year by year).'' I would have said that everything is obligated in Ma'asros. The pasuk says, "all of your seed crop''. This only teaches about grains. What's the source for beans and fruits of the tree? The pasuk says, "that the field produces, year by year.''

Perhaps garden seeds that are not edible should be included? The pasuk states "your seed crop'', but it also states "that the field produces, year by year'' (which seems to include all species that grow in the field). How is this? Only include that which is similar to grain, in that it is edible, guarded and grows from the ground. This excludes inedible garden seeds.

Some learn the obligation of Ma'asros from another pasuk - One cannot learn from the earlier pasuk, since 'you shall tithe' is a generalization and "all of your seed crop'' is a specification - a generalization followed by a specification means that only that which was specified is included in the generalization.

If so, only grains would be included. What is the source for beans? The pasuk states (Vayikra 27:30), "Any tithe of the Land, whether from the seed of the land or the fruit of the tree, it is Hash-m's.'' ('Any tithe') includes beans. ('from the seed of the land') includes seeds of garlic, cress and rocket.

Or perhaps I should include the seed of wild Luf, leek, onion, turnip, radishes and other types of garden seeds that are not eaten...? The pasuk states, "from the seed of the land'' but not all of the seed of the land. And the phrase "fruits of the tree'' includes all fruits of the tree.

I might have thought to include Shita, Tzalmona and Gedira carobs (even though they are not human food)? The pasuk states "from the fruits of the tree'' but not all of the fruits of the tree.

What's the source for vegetables? Isi ben Yehuda says that the obligation to tithe vegetables is Rabbinic.