When somebody needs dough in order to make bread, they have to separate challah (a portion) and give it to a Kohen (priest). The obligation of challah and the prohibition against eating chadash (new crop) apply to five species of grain. We’ll talk about these two mitzvot (commandments) over here. We’ll first start talking about challah, and then we’ll get back to chadash. The Mishnah says: Those that are made from wheat, barley, spelt, oats, and rye are obligated in the laws of challah. If a certain amount is made, a person has to contribute some to the Kohen. The grains also join with one another to reach that minimum amount needed for the challah. For the challah obligation, if you have some, for example, wheat, and you have some barley, and the doughs were created together, they could be mistaref, they could combine, in order to reach that minimum amount needed for the challah obligation.
These grains are all subject to the prohibition against eating chadash before Pesach (Passover). You’re not allowed to eat these before Pesach. The new crop of any of these species is not allowed to be eaten before the omer (sheaf offering) is offered on the 16th of Nisan (Hebrew month), the second day of Pesach. The new crop of any of these species is not allowed to be harvested either before the grain of the omer is harvested.
What’s considered to be new crop with the prohibition of harvesting? If these species took root before the omer was harvested, then once the omer is harvested, they become permitted to harvest and eat. If they were already rooted deeply, then the omer allows them. But if they did not take root by that time, even though they were planted already, but hadn’t taken root in the ground, and the harvesting of the omer happened, and then they took root afterward, they’re forbidden until the coming of next year’s omer. They’re not allowed to be harvested or eaten until the next year’s omer is harvested. So it all depends on when they take root. If they took root before the omer, then they’re allowed by the omer. If they take root after the omer, then they have to wait for the following omer in order to be allowed.