3,411. Trading Produce

Hilchos Maaser 5:4

If two people exchange produce, each with the intention of eating it, the obligation to tithe both sets of produce goes into effect because they have each “bought” detached produce. If they intend to harvest one another's crops, the obligation does not yet take effect because the sale of produce only obligates one in tithes if the labor of the produce has been completed, as has already been discussed. If one of them exchanges for produce to eat and the other one exchanges for produce to harvest, the one who bought it to eat is obligated in tithes while the one who bought it to harvest is not yet obligated in tithes.

Hilchos Maaser 5:5

Let’s say that one person tells another, “Go take 20 figs of mine and I’ll eat my fill of your produce,” both are exempt from tithes. This is because such an exchange is not considered comparable to a sale. If he gathers the produce and eats from it, then he is obligated in tithes.