Question: In my world human(oid)s are not born anymore, they are grown in pods which mirror the conditions of a natural womb.

Children are educated before birth and are "born" as fully mature adults with a standard education ready to join society.

How long would this process take? I assume that artificial growth could be much quicker than a natural 18-20 year period. Could a human be grown in a year? A decade?

Answer: 
A year? No. Babies already require 9 months in the womb to get to where they get. You're limited because many processes in growth require chemical processes that simply take time. Humans simply aren't cars to be manufactured.

A decade? Now its getting interesting. It is reasonable to assume that a human could grow faster in a "perfect" environment with genes to leverage that perfect environment. Its entierly possible we could reach "fully grown" in a decade. However, the womb would probably have to be adjusted. Many thing a human body needs require things that challenge their motion (so they can learn which muscles are doing what). The humans would be gloriously clumsy unless they got Physical Education as part of their standard education in the womb.

A standard education in the womb you say? That education process might be very daunting indeed. You may be able to physically produce a human in a decade, but you may find it hard to properly educate them that fast.
Certainly not in a year, no. Growth is limited by multiple things, for example:

* bone ossification - bones need to both grow laterally and also get ossified. There's a few values for bone growth in children [in this paper](http://www.boneandjoint.org.uk/content/jbjsbr/44-B/1/42.full.pdf) - basically, a few centimeters a year.
* skin needs to grow. And the larger a person gets, the greater their surface gets. Think about how long wound healing can sometimes take.
* neurons in the brain need to grow - your education alone will need several years, and will often have to wait for the growing brain to catch up

You can estimate a lower limit from two scenarios:

* there's people who never stopped producing human growth hormone, which is one of the factors in determining when children grow. [Robert Wadlow](https://en.wikipedia.org/wiki/Robert_Wadlow)'s body never stopped growing until he died at age 22 and roughly 270 centimeters. If he was born at around 50 centimeters, that's roughly 10 centimeters a year.
* the "peak growth velocity" in teenagers, who grow the fastest, is also [around 9 centimeters a year](http://pediatrics.aappublications.org/content/102/Supplement_3/507)

So basically, 10 centimeters a year would be a believable growth rate, meaning from 50 to 180 centimeters, you'd need about 13 years. Under optimal conditions, with great nutrition etc., a decade sounds believable. 

However, you might want to keep in mind that this is only lateral growth. [The human brain isn't considered fully mature until the mid-20s.](http://hrweb.mit.edu/worklife/youngadult/brain.html)