Yes, you can use hash instead bud. In fact, the edibles made with hash are better than the ones made with bud, cause they are purer.

For the amount of hash you need... when i make edibles i use something like 6-10x the amount of hash i would usually smoke. Note that this amount is for one person, and for one dose, what means if i make a batch of brownies with this amount of hash, i would need to eat the entire batch to get high. If you were to make it for more people, or for several doses in a batch, multiply the amount of hash properly.

Remember that edibles works better (sometimes only work) when eaten with an empty stomach, and that it takes some hours 2-4 to kick in.

So, good luck and enjoy!

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"Everything we do, everything we are, rests on our personal power. If we have enough of it, one word uttered to us might be sufficient to change the course of our lives. But if we don't have enough personal power, the most magnificent piece of wisdom can be revealed to us and that revelation won't make a damn bit of difference." Don Juan Matus - Tales of Power