1. The term 'email nurturing' is a Sales-Marketing term btw, not an IT term, and as you probably know there is equivalent term in Malay yet.
2. It is a feature of a marketing campaign known as 'lead nurturing campaign' or 'drip campaign' where time-based information are sent out to customers and potential customers in order to inform them of an offer and, over time, lead/motivate them to take some sort of action, like taking advantage of your offer.
3. In this case, the nurture campaign uses time-based emails [which doesn't make it an IT term per se].
4. Based on the concept, I think the better Malay word to use in the term is 'didik' and not 'pupuk'. Alternatively, 'bimbing' may work too, but I personally prefers 'didik'.
5. The term should also be translated as 'e-mel didik' [i.e. making it a 2-word term] instead of using the usual convention of flipping adjective & the noun it modifies when translating from English into Malay. This treatment, in my opinion, gives the concept a more accurate definition. The other way, 'pupuk/didik e-mel' may confuse people into thinking that it is the emails which are being nurtured instead of emails being used for a customer nurturing [or guiding/psychological pressuring, if you will] process.

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Note added at 12 hrs (2020-10-24 15:28:37 GMT)
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"...there is NO equivalent term in Malay yet."

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Note added at 13 hrs (2020-10-24 17:05:12 GMT)
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"...I personally prefer 'didik'"

Azimah, sorry for all the typos, but for some reason KudoZ 'edit answer' option has been removed. Hope this oversight by ProZ is corrected soon. Not being able to edit their answers before submitting is bad for practitioners in this industry - it gives their professionalism a bad impression.