Hilchot Sukkot: What makes a set of Arba'at Haminim kosher?
What makes a Lulav Kosher?
The general requirements for a kosher lulav (date palm frond) are that the spine of the lulav must be at least 4 tefachim (where 1 tefach = 8-10cm) and it must have leaves that cover the spine. It is also necessary that the lulav be fresh and mostly straight, and ideally should not have a tiyomet (highest middle two leaves extending directly out of the top of the spine) that is split more than a majority of the length of the leaf.
Although they are sold at a premium, taking a Deri Lulav will often save hours of time searching through hundreds of Lulavim to find one that is perfect. Deri Lulavim are typically very green, very straight, with an extremely strong tiyomet that is tightly closed to the very tip.
Some people look for a lulav with a Kora, which is a brown bark that surrounds the lulav when it grows and sometimes wraps around the tiyomet to help ensure it is closed, but on the other hand, some avoid a Kora in case there are other problems hidden underneath that can’t be seen.
What makes an Esrog Kosher?
The general requirements for a kosher esrog are that it is not grafted, is not entirely green, and must be at least the size of an egg. Furthermore, there must not be any discoloration of any size on the chotam (the upper inwardly sloping portion of the esrog) that is noticeable upon a normal glance without staring at it carefully.
If the pitom falls off or the stem on the bottom of the esrog is completely removed, the esrog is also not kosher. Some Esrogim are grown on the tree without a pitom and are 100% Kosher. These are ideal for those with 'active' children.
What makes Hadassim Kosher?
The general requirements for kosher hadassim are that each branch should be at least 3 tefachim in length and each branch should have many clusters of three leaves (each cluster sprouting from one level) along its length.
One should use three hadassim branches for the mitzvah.
What makes Aravos Kosher?
The general requirements for kosher aravos are that each aravah branch should have a green or red stem and span at least 3 tefachim in length. The leaves of the aravah should be long and narrow with smooth edges.
One should use two aravos branches for the mitzvah.