I just found a post in a thread of the Crafting section of ESO's forums that may prove helpful for Provisioning. Following is a quote:
"Collect nothing but recipes until you get near the end of the first zone after the starter areas. Don't keep extra recipes because you may want to use it on another character in the future. Recipes are plentiful and easy to get.
So are provisioning supplies. Don't waste your time gathering them to craft level 1 consumables. Wait until you have level 15+ recipes and just before you move on to the next zone, do a hard target search for the items you need to craft those level 15 recipes. Do it while questing if you prefer, but only focus on the items needed for the level 15 recipes. You can make those without investing any skill points in provisioning and they give a lot of XP. Crafting a single level 15 consumable will get your provisioning from level 1 to 2. So why waste time crafting level 1 consumables? Once you hit provisioning level 20, you can invest a skill point into the next tier of consumables. At that point, you don't need any of the low level supplies any more (thin broth, drippings, mutton, etc.). The level 20+ recipes require entirely different things (broth, cooking fat, venison, etc.).
I followed this exact plan. I started leveling provisioning 2 days ago and in a few hours I was provisioning level 45. I got it to level 50 last night based mostly on the supplies I found in a single mini-dungeon. I forget the name of the dungeon, but it's the one in south-central Stormhaven with Dimitri as the "boss". He drops blue quality leather pants. That dungeon has an absolute ton of crates and barrels.
I make stacks of the best consumables I want and can use and only collect more supplies when the consumables run low, or I am able to craft/use a higher level consumable. The point is, I don't ever need to store provisioning supplies because they are so easy to get."
That actually makes some sense to me. I think the first tier of provisioning goes until 19 and at 20 you can unlock tier 2. So it would make sense to get a level 15 or so recipe, get the mats needed for that and then just get to level 20 all in one fell swoop. Then repeat with the next tier level range.
For alchemy, I can see it being the same way. All the ingredients are the same with the exception of the water used. Wait until you have Pristine Water, not the noob water we get at low levels (hehe), then craft with the plants gathered using the pristine water. I'll have to test that.
For the other crafts, is there a good source for showing what level of crafting you have to be at to unlock the next tier?