In the description in the Torah of the agricultural richness of the Land of Israel, the seven principal crops are mentioned:
A land of wheat and barley, of vines, figs, and pomegranates, a land of olive trees and honey. -Deuteronomy 8:8
Over the years, many new cash crops have been introduced; some have taken on symbolic significance like sabras and oranges; others simply make their quiet contribution to the economy and the quality of life (e.g., cucumbers, avocadoes, melons ). Israel is by no means self sufficient in grain, and we eat dried figs imported from Turkey. Nevertheless, the seven species remain not only a traditional concept, but still symbolize for us the native produce of this land, and connect the modern landscape to the biblical description. This season, leading up to Shavuot, the feast of the first fruits, seems an appropriate time to examine the seven species and their place in our tradition.
The Lord spoke to Moses, saying: Speak to the Israelite people and say to them: When you enter the land that I am giving to you and you reap its harvest, you shall bring the first sheaf [omer] of your harvest to the priest. He shall elevate the sheaf before the Lord for acceptance in your behalf Until that very day, you shall eat no bread or parched grain or fresh ears... -Leviticus 23: 9-14
Barley and wheat have both been cultivated in Israel since ancient times. Barley seems to be associated with a less developed society, growing in poorer soil, requiring less sophisticated agricultural knowledge. It was considered the most basic foodstuff in assessing the value of a field, one calculated the amount of barley seed needed to seed it [Leviticus 27:16]; it was definitely less valuable than wheat [II Kings 7:1]. Later, in Midrash Sifrei Bamidbar , we read: Why are you eating barley bread? Because I have no wheat bread!
Barley ripens earlier than wheat [Exodus 9:31]. It is the harvest referred to in the above passage about the bringing of the omer offering. The practice was to cut the first sheaves of barley the day before Pesach, and to bring an offering from this early harvest on the second day of the festival (i.e., the first day of chol hamoeid). Until this was brought, it was forbidden to eat from this new crop. This perhaps helps to explain the elimination of all old grain products in preparation for Pesach: we clear away the old to make way for the new; then for the week of Pesach we eat only matzah (made from a portion of last years crop that was carefully protected all year from dampness and from contamination by leavening), and afterwards we may enjoy the new crop freely, in any form.
The barley harvest goes on for nearly two months before the wheat ripens. Barley is no longer a significant crop here; it is used primarily as animal feed. As I drive through the Jezreel valley each week on my way to a teaching assignment, I notice broad fields of wheat that are now characteristically pale green, wavy in the breeze they have not started to turn golden yet.
None of the above was relevant, of course, during the forty years we wandered in the desert, for there we ate manna all the time. The first thing we did after crossing the Jordan River behind Joshua was to observe Pesach, and
On the day after the Passover offering, on that very day, they ate of the produce of the country, unleavened bread and parched grain. On that same day, when they ate of the produce of the land, the manna ceased. -Joshua 5:11-12 (from the haftarah for the first day of Pesach)
So it seems that one of our first experiences upon arrival here was to make the transition from manna to barley, to put down roots, to become dependent on the land (and our working of it); once we got here, there was no more free lunch.