First, it may not be valid to assume that creation was bound by the laws of science as we now understand them. Why should we assume that the very first plants grew by photosynthesis in the same way that plants do now? Or if we do, why not assume that the primordial light created on the first day was enough to produce this effect?
But setting all that ...
The midrash in Sh'mot Rabbah (2:5) offers some explanations:
Why fire? To inspire him with courage so that when he comes to Sinai later he is not afraid of the fire.1
Why a thornbush? R' Yehoshua b. Karchah said: to teach that no place is devoid of God's presence, not even a thornbush.
R' Eliezer said: just as the thornbush is the lowliest of all trees in ...
These were some of the final words of R' Eliezer, as he lay on his deathbed.
'Moreover, I have studied three hundred, (or, as others state, three thousand laws) about the planting of cucumbers [by magic] and no man, excepting Akiba b. Joseph, ever questioned me thereon. For it once happened that he and I were walking together on a road, ...
On chabad.org it says the following:
On the way out of the cemetery, it is customary to pull out some
grass, throw it back over the shoulder, and recite the passage below.
This symbolizes the Resurrection of the Dead in the era of Moshiach,
when the body will awaken and return from the dust of the earth, as it
is written, "And may they blossom out ...
You asked: Is this a Jewish minhag? If so, what is the source for it?
Yes. it is mentioned in the Kitzur Shulchan Aruch 199:10 - סימן קצט - דין הקבורה ובית הקברות
"The custom - when leaving a cemetery - is to pluck some grass and throw it behind one's back, and say זָכוּר כִּי עָפָר אֲנָחְנוּ - remember that we are dust."
You asked: What does it mean?
After Sukkos is over (and you don't need them for mitzvah purposes
anymore), collect your leftover aravah branches that you used for
ד' מינים and הושענות. (You may also want to collect other's
branches, because many people just leave their הושענות in shul
when they're done with them -- that's another 5 branches per
Place the branches in ...
The reason not to water an animal is that it was banned by rabbis because it takes too much time and effort (tircha) (e.g., Aruch Hashulchan 324:1). They built exceptions into the ban in cases of need (such as, usually, when the animal depends on you for food) (e.g., 324 passim). The reason not to water a plant is because God said you can't make a plant grow ...
The Mishnah about Magic cucumbers appears in Sanhedrin. It discusses the case of whether a person used an actual maseh or just "achizas enayim" to raise cucumbers:
ז,יא המכשף--העושה מעשה, ולא האוחז את העיניים. רבי עקיבה אומר משום רבי יהושוע, שניים לוקטין קישואים--אחד לוקט ופטור, ואחד לוקט וחייב; העושה מעשה חייב, והאוחז את העיניים פטור.
The Rambam (Kilayim 1:3) and the Shulchan Aruch (YD 297:2) explicitly rule that the issue of Kilaei Zeraim (planting mixtures of edible seeds (except grapes)) only applies in the Land of Israel and a Jew can even plant his own mixtures outside of Israel on purpose.
The Bach in O.C. Siman 167 has a nice explanation of this.
He starts by pointing out that the word "hamotzi" is the preferred word for the blessing, even though the word "motzi" would suffice, because "hamotzi" implies both past and future tense (Berachos 38a). The intent, he says, is both on this bread which came out of the ground, and on the bread that ...
I've tried the paper towel/aluminum foil (my father's method) idea, keeping them in the fridge, and keeping them in water. One year I got a whole lot of them and experimented with around seven different methods for each pair, to see at the end of the week which method would be the best.
The winner (and what I've been doing every year since then): wet them ...
Shulchan Aruch HaRav 336:9 (My translation) -
ולפיכך מי שאוכל בגינה צריך ליזהר שלא ליטול ידיו על העשבים מפני שמשקה אותם...אבל מותר להטיל עליהם מי רגלים או יין ושאר משקים מפני שהם שורפים אותם ואין מצמיחים אותם אלא מים בלבד וראוי ליזהר אף במשקין
Therefore one who eats in a garden must be careful not to wash his hands on the grass since he is ...
According to a shiur I heard recently, there's a Machlokes Rishonim (early Poskim argue) about whether the Mitzva of Shmitta is:
Don't work your land - but your land may work.
Your land may not work - no matter who and how the work involved.
This - apparently - directly affects the answer to your question, as well as to whether you may lease/sell your ...
It's actually a machloket haposkim (argument among the decisors), with the point of contention exactly that raised in the question.
From the CRC:
Some (Chayei Adam 51:17 & Nishmas Adam 152:1, Yechaveh Da’as 6:12, and Machzeh Eliyahu 25-29) hold that the bracha is shehakol because the wording of the bracha “Boruch…who creates the fruit of the earth” (...
The Mishna on Megilla 28a rules that a destroyed synagogue retains holiness, and if grasses grew on it they should not be picked because they add to the feeling of despair. (The subsequent Gemara on 29b discusses picking the grasses and leaving them there, though the Rambam (Perush HaMishna 3:4) and the Mishna Berura (OC 151 sk 29) both understand this to be ...
The Chochmas Adam 89:1 wrote that the Vilna Gaon abolished the minhag of decorating the synagogue with trees in honor of Shavuos because of the problem of Chukkas HaGoy (i.e. the practice of decorating a tree for the Christian's Holiday). The Chochmas Adam held that such a problem would even justify nullifying a practice mentioned (but not commanded) in the ...
There are two problems as explained at this article
There are two major kosher concerns with “pure maple syrup.” First, an
observant Jew is required to turn on the evaporator because only an
observant Jew is allowed to “light the fire” that cooks a kosher food
item. Second, while the sap is boiling, farmers drip animal fat into
the mixture to keep ...
R Avrohom Yeshaya Karelitz (Chazon Ish Shevi'it 5:12) writes that were we to give Maaser Rishon nowadays to Leviyim on the basis that they claim the Levi Aliya in Shul, more people would lie and pretend to be Leviyim because of the financial benefit.
However, most authorities seem to think that Maaser Rishon (taken from certain Tevel) should (at least ...
I was just referred to "How to keep your aravos fresh throughout sukkos: The definitive guide for frustrated palm-frond wavers", an apparently anonymous document describing a series of nine experiments, carefully testing different strategies for keeping Aravot fresh. Read the whole thing to see all of the strategies tested and all of the results, including ...
When one picks fruits owned by a Jew in Israel, he is allowed to snack on them (אכילת עראי) until they become designated for maaser (נקבע למעשר), or, if he is planning on selling them, until he finishes his work on the harvest (גמר מלאכה). After that, he cannot eat from them at all until properly tithing them.
The most common ways of designating for maaser ...
It's pure geometry.
The simplest example of this in 3D is that the surface area of a hemisphere is double the surface area of a flat circle, so if you grow things on the surface you have double the area (wikipedia.org/wiki/Sphere).
Area of circle = pirr
Area of curved part of hemisphere = 2*pirr
Obviously, this is just a simple example to ...
In Psalms 104.14 it is written "Lehotzi lechem min ha'aretz" צְמִיחַ חָצִיר, לַבְּהֵמָה, וְעֵשֶׂב, לַעֲבֹדַת הָאָדָם;
לְהוֹצִיא לֶחֶם, מִן-הָאָרֶץ. I have always assumed that this was the source of the text, and a shiur from Rav Ya'akov Nagan from Yeshivat Othniel also gives this source.
The Talmud (Sanhedrin end of 70a) alludes to Adam drinking wine - although it isn't exactly clear how that would work given the time frame - saying that Noach should have stayed away from wine, learning from Adam with the sin of the Eitz Hadaas which was caused by wine - according to the opinion that the tree was a grape vine.
Ralbag has two explanations of the order of creation that can address this. The first explanation is that everything existed at once. The sequence delineated in Genesis is just the order in which they were revealed. This is likened to someone who plants various seeds at the same time but some sprout before others. The second explanation is that existence is ...
It is only prohibited to cut down trees for no purpose, but what "purpose" includes is hard to define. Rambam Laws of Kings 6:9 deals with your case directly, however:
כל אילן סרק מותר לקוץ אותו ואפילו אינו צריך לו. וכן אילן מאכל שהזקין ואינו עושה אלא דבר מועט שאינו ראוי לטרוח בו. מותר לקוץ אותו.
It is permissible to cut down any non-fruit bearing ...
Strictly speaking, Peah doesn't have to be from the corners of the field. (Mishnah Peah 1:3). The mishnah says that the minimum measure of a field that should be reserved for peah is 1/60th (Mishnah Peah 1:2) although there's no maximum, so I would assume the same ratios would apply to a round field. Peah is also usually left to one side of a field, so it ...
Have there been any (scientific) studies that prove the benefits of Orlah?
Well, as you will see from the answer to your second question, it's not about benefits.
You can see from articles like this one that most fruit trees don't bear (real) fruit for the first 3 - 4 years.
You then asked:
What is the reasoning behind Orlah prohibition?