Q:

A correct word for 'learnful'

I’m looking for a word that would fit in the sentence it was a very learnful experience: i.e., I learned a lot during that experience.
Learnful feels correct to me, but the dictionary disagrees. It’s possible I’'m incorrectly assuming there is an English equivalent to the Dutch word leerzaam, but I can’t imagine there is no word to convey such a meaning.
Google Translate suggests instructive or informative, but those seem to either mean providing ways of doing things or factual information. What I want it to mean is more abstract, including things like skills and insights and overall growth in competency.

Interestingly, I do now think that the Dutch word leerzaam might not be translatable to English after all; so if someone (Dutch) has some thoughts on this, it might be of interest, since the languages are so similar. 
I’m trying to think of a nice counterexample, but the best I can come up with now is this:

Although it was a setback that my roof collapsed, it was an educational experience, and I would never start a home improvement project without proper preparation again.

That does sound pretty awkward in English, right?

A:

The term instructive can be used in the sentence:

Conveying knowledge or information; enlightening.(AHD)

or educational: 

Serving to educate; instructive: an educational film.(AHD) 

A:

It was a very edifying experience.

Edifying:  adjective Providing moral or intellectual instruction

ODO

A:

Your original sentence "It was a very learnful experience" would normally be phrased "The experience was very educational" or "It was a very instructive/informative experience" 
Educate, inform, instruct, teach, have similar meanings and can be substituted for leerzaam when translating to English.  Instructive is likely the one that best fits your intention.  The context of the sentence would clarify what was learned.
Leerzaam in English would be educational, informative, instructive.
Instructief and informatief in fact are given as Dutch synonyms for leerzaam
As so often happens, the word does not have an exact counterpart in English, but rather a short list of words with similar meanings that cover various specific uses of the word being translated.

