Commentary for Maasrot 1:5

איזהו גרנן למעשרות (what is their harvesting time for making them liable for tithes) – when are the fruits appointed for tithing and it is forbidden to eat of them as an incidental meal like the grain in the threshing floor for even though the produce arrived at the season of tithing, it is still permitted to eat from them an incidental meal until it would be their harvesting time.

What is considered a “threshing floor” for tithes [i.e. when does produce become liable for tithes]?
Cucumbers and gourds [are liable for tithes] once he removes their fuzz. And if he doesn’t remove it, once he makes a pile.
Melons once he removes the fuzz with hot water. And if they he does not remove the fuzz, once he stores them in the muktzeh.
Vegetables which are tied in bundles, from the time he ties them up in bundles. If he does not tie them up in bundles, until he fills the vessel with them. And if he does not fill the vessel, after he has gathered all that he wishes to gather.
[Produce which is packed in] a basket [is liable for tithes] after he has covered it. If he is not going to cover it, until he fills the vessel with them. And if he does not fill the vessel, after he has gathered all that he wishes to gather.
When does this apply? When one brings [the produce] to the market. But when he brings it to his own house, he may make a chance meal of it, until he reaches his house.
This mishnah begins dealing with the issue of when produce become liable for tithes (see introduction). The mishnah calls this a “threshing floor” because at the threshing floor grain becomes liable for tithes. By extension, all produce is liable for tithes once its processing has been completed. After this point it is prohibited to eat even a chance meal from this produce without tithing it. Before this point one can eat a “chance meal” without tithing, but not a “fixed meal,” one which is more formal.
Sections one and two: The processing of cucumbers, gourds and melons is completed once the owner removes the “fuzz”, some very fine hair, that is on them. After that point, they are liable for tithes. If he doesn’t intend to remove the fuzz, then the processing is complete once he has made them into a pile, or once he has stored them in the “muktzeh” a storage area behind the house.
Sections three and four: Vegetables which are usually tied up in bundles in order to be brought to market, are liable for tithes as soon as they are tied up in bundles. Similarly, produce which is usually stored in baskets is liable to be tithed once it is put in a basket. In both cases, these are the final stages in their preparation. If he doesn’t intend to do this stage, either tying up in bundles or covering them in a basket, then they are liable for tithes once he has filled up a vessel with them, a vessel which he will use to bring the vegetables to the market. Finally, if he isn’t going to even put them in a vessel at all, then they are liable for tithes as soon as he has gathered a sufficient amount that it is worth it for him to bring the produce to the market. Note that if the last normal stage is not going to happen, then the previous stage becomes the completing stage.
Section five: The rules in the above sections apply only when he is going to take the produce to the market. In such a situation, this processing is relevant. However, if he is intending to take the produce home, then the produce is not liable for tithes until he brings it into his house. He may make a “chance meal” from the produce until he brings it home.

משיפקסו – as soon as their blossoms are removed and this is the hair that grows on them when they are small and when they ripen sufficiently, it falls out.

משיעמיד ערימה – when he makes of them a heap/pile.

משישלק (as soon as the gardener trims them) – trimming for a melon is like blossoms falling out for gourds.

מוקצה (until the melon is stored away) – because we don’t make piles from the melons, but rather spread them out and the place where we spread out the fruit is called a storage.

ירק הנאגד (vegetables put up in bunches when they are tied) – for it is the manner to sell it in bunches.

ואם אינו ממלא את הכלי – such as the case when he wants to fill two or three utensils, he eats an incidental meal from each one until he fills up the concluding one.

כלכלה (basket containing chosen fruits designated for use) – He who harvests/gathers vegetables into the basket containing chosen fruits, which is a basket.

עד שיחפה – the vegetation with the long and thin foliage of a palm-branch spreading from the stem or with leaves that are used to cover it.

בד"א – that this is their harvesting time for making them liable for tithes.

במוליך לשוק – to sell [in the marketplace] for it was not dependent upon his intention lest he find buyers and the produce will be subject to sacred gifts being set aside (and as such forbidden to be consumed until such time), that the sale will establish it for tithing.

אבל במוליך לביתו אוכל עראי עד שמגיע לביתו – since the matter was dependent upon his intention and the produce would not be subject to sacred gifts being set aside until he arrives home for the eatables forbidden pending the separation of sacred gifts are not liable for tithing until he sees the house, as it is written (Deuteronomy 26:13): “I have cleared out the consecrated portion from the house; [and I have given it to the Levite, the stranger, the fatherless, and the widow, just as You commanded me.”