Grafting a lime scion onto a lemon rootstock to produce two fruits from the same tree
Question
I have a lemon tree in my garden. I want to graft limes onto it in addition to lemons, so that I will have two different types of fruit from the same tree, and also so that I don't have to wait three years for the first fruits. Is this permissible to do this lechatchilah? And what about grafting a sweetie (pomelit) onto a pomelo tree? A sweetie onto a grapefruit tree? A mandarin or clementine onto an orange tree?
I see that you divided citruses into three different halachic species (lemon; orange, mandarin, and clementine; and pomelo, sweetie and grapefruit). Would it therefore be permissible if I use a scion and rootstock pair from the same family?
Answer
Regarding normal grafting, if a non-Jew grafted and planted the tree, it is permissible to maintain a tree composed of different citrus species - relying on the Chazon Ish's ruling that these are safek mino (there is a doubt regarding whether they are the same species). However, this refers to a situation in which only the fruits of the scion are produced by the tree.
The question at hand involves a tree on which both grafted and naturally growing fruits exist. This is an excellent question, which Torah VeHa'aretz Institute's rabbis discussed last week: whether it is possible in the garden of mitzvot that we are establishing now to plant a multi-fruit citrus tree. In 5774, Rabbi Yoel Friedman ruled on this matter in light of a nursery selling grafted multi-fruit trees in Sde Yaakov, a religious moshav in Northern Israel. We then forbade buying a multi-fruit tree that includes different citrus species (even if the non-Jew grafted and planted), because ultimately, the visual aspect here is very significant and remains throughout the tree's lifetime (Rabbi Shlomo Amar explicitly forbade it as well, 5757; Shema Shlomo III YD §12; However Rabbi Yitzchak Yosef allows it: Yalkut Yosef YD 295:16).
However, your question pertains to a multi-fruit tree, which follows the halachic definition published by the Torah VeHa'aretz Institute of the citrus species definitions, meaning it is ostensibly different varieties of the same fruit. On the other hand, there is still an appearance of fruits that are ultimately different from each other Institute's rabbis were divided on this: they all agreed that there is no explicit prohibition here, but they were divided on whether it is permissible lechatchilah.
Some rabbis maintained that it is permissible lechatchilah, and it is similar to having black and white figs on the same tree (perhaps the intent of the Mishnah is green and purple figs; see Mishnah Terumot 4:8), which is permissible lechatchilah. Some rabbis wrote that there is a distinction between different types of species: it is easier to permit lemon and lime because they are very similar; the same is true for pomelo and sweetie. Grapefruit and sweetie and grapefruit and pomelo are somewhat more distant, but still relatively similar. Mandarin or clementine on an orange tree is already less similar to one another, and here more rabbis tend to be stringent and discourage people from grafting these types onto one another.
It is also noteworthy that there were also posekim that refused to classify citruses with easily removable peels (mandarin and clementine) in the same halachic category as oranges due to the difference between them; that is, they prohibit farmers from grafting them on top of each other. We at the Institute did permit it lechatchilah, but only for farmers for whom this is their livelihood and when there is a pressing need, but not for private individuals, and especially not when two types of fruits remain on the same tree.
Some maintained that even grafting lemon and limes onto one another should be prohibited: primarily due to the concern that people will see a Torah observant Jew grafting a multi-species tree with lemon and lime and then think that all citrus species are permissible to graft onto one another, not knowing the difference between the subcategories of citruses. Subsequently, in their garden they will plant trees that are lemon and orange grafts. This, then, can lead to a third person grafting a tree of almonds and cherries, which is already an outright Torah prohibition.
Conclusion
Rabbi Yehuda Amichay forbade maintaining multi-fruit citrus trees in one's garden, buying them and certainly actively grafting such trees (even if the grafting or planting was performed by a non-Jew), due to appearances, with the exceptions of lemon and lime; pomelo and sweetie; and different varieties of apples. He permits grafting these fruit tree combinations lechatchilah even by a Jew, since they appear to be the same type of fruit.
This holds true for both private individuals and for farmers. For this reason, with the exception of the combinations noted, nursery owners should not sell multi-fruit citrus trees.
Orlah – when a graft is performed, the orlah year count is determined by the rootstock. Therefore, if the rootstock is mature, the fruit produced by the scion will be permissible, even if it developed within the year the graft was performed.