Sukkut: a Grafted Etrog
Question
I see that it says on all the etrog boxes “not grafted.” What exactly does that mean?
Answer
The Torah forbids grafting trees of two different species (kilei ilan). All over the world, etrog trees are grafted: either onto lemon or hushhash trees. The issue of grafted etrogim arose in the late 16th century, and the vast majority of poskim forbid using a grafted etrog as part of the arba minim (while they can be eaten).
Why can’t a grafted etrog be used for the arba minim?
The main reason is that this is a mitzvah haba’a ba’aveira, a mitzvah performed by way of a transgression (the gemara cites the example of a stolen lulav), since grafting different species is a Torah prohibition.
Another approach views such etrogim as the products of two trees (an etrog scion and a lemon rootstock), meaning that the etrog is not 100% an etrog. Note that according to current scientific studies, the fruit’s genetic makeup comes only from the scion (=the etrog tree), and not from the rootstock. That is, if we plant seeds from a grafted etrog, they will grow as etrog trees for all intents and purposes, without any lemon rootstock influences.
Abroad, there are places where local farmers grow in the same orchard non-grafted etrogim for Jews and grafted etrogim for non-Jews (for candied etrogs, jams, liquor, and cosmetics).
All kashrut agencies worldwide ensure that etrogim they certify are not grafted, so you can be sure that etrogim with kashrut certification are not grafted.
If you purchase an etrog tree for your garden, make sure it was not grafted in the nursery. And if you receive a home-grown etrog, make sure it was from a tree that wasn’t grafted.
See here for an article about grafted etrogim.