This is why I do not buy level 2 farming early on. My villagers exist mainly on mushrooms (yes you can find enough) until the crops start to grow. Then I turn them all temporarily into farmers and sit on them until they have all the crops in.
In fact, in my most recent game the kids found enough mushrooms to feed the tribe and enough collectibles to buy level 2 engineering all on their own (with a little help from me of course).