hi,
i will try to answer your questions.
1. no, powder and fresh juie are NOT! the same. don't believe the hype of ads that tell you otherwise. i have seen fresh wheatgrass cure gangrene with my own eyes, no powder is ever going to do that. the fresh cut and juiced grass has all of the vital nutrients the body needs along with chlorophyl, the life force is still very active and strong. a powder is dead, that doesn't mean its worthless, there is a lot of benefit to it, but it does not have the life force that fresh grass jucie has.
the nutritional difference between wheat and barley grass is neglible. barley grass is more bitter tasting but easier on the stomach. so if you are like me and have a sensitive stomach you may want to go with the barley. the wheatgrass is much sweeter, but also can be harsh on the stomach.
the nutritional value of wheatgrass will vary depending on the quality of the soil it is grown in. but even grass grwon in poor soil is high in nutrients. and juice from grass grwon in good soil is the most nutritionally packed liquid on earth, bar none.
the chlorophyl is the key, it is the most potent blood purifier, detoxer and rebuilder there is. it also begins to die the instant you cut the grass. how much chlorophyl can still be alive in a dried powder? not much i say. cutting the grass, then quickly
juicing it and drinking the juice is key to getting the chloropyl. i know nothing about drinking bood.
alfalfa is tremendous. one of the most beautiful and majestic creatures on earth - the arabian stallion - thrives on nothing but alfalfa. but again fresh would be best.
i dont know where you can get plain wheatgrass powder, though "green magma" is mostly barley grass and that would be about the same thing.
the best grass is grown outdoors. you can cut and juice any grass that grows outside, it doesn't have to be wheatgrass. i have juiced all kinds of wild growing grasses in different parts of the country. they all juice fine. are you near a river or pond where grass grows? if so you can cut that grass and juice it, it will be better than anything grown inside or from a can.
let me know if you have any other quesitons.
ff