I know that in Spanish adjectives go after the nouns which they describe, as opposed to English where adjectives go before. So it is correct to say "la casa roja" in Spanish as "the red house" in English. However, I have come across the phrase "Yo tengo suficiente ropa." Why does "suficiente" go before the noun "ropa?" Isn't "suficiente" an adjective?
The difference you see between putting the adjective before/after the noun applies only to calificative adjectives. There are several other types of adjectives where this just does not work.
Suficiente is a 'quantifier', an indefinite adjective like mucho, poco, bastante, ningún, tanto, demasiado and others.
EDIT: I answer this question without considering the interesting observation that "suficiente" may antecede or precede the noun, unlike other similar adjectives (as indicated by the comments and the response of fedorqui).
Yo tengo suficiente ropa. / Yo tengo ropa suficiente. (OK)
Yo tengo bastante dinero. /
Yo tengo dinero bastante. (not work)
One way to interpret this (and this is an opinion) is considering that the indefinite adjective 'suficiente', for stylistic reasons rather than semantic, can be understood sometimes as a qualifier instead of quantifier, in which case is placed after the adjective as would with another calificative.
Interesting question about a thing I had never noticed!
Not all the times the adjective comes before the noun. It is indeed the most normal location, but placing it differently is also correct.
In general, using the form
noun sounds a bit more poetic:
la blanca paloma would appear in a written, nice text;
la paloma blanca is merely descriptive.
However, and this I just learnt by checking information for the question, the adjective before the noun can also give a meaning of subjectivity:
From la posición del adjetivo in Lingolia:
Normalmente, en español el adjetivo va detrás del sustantivo. la mesa negra
En ciertas ocasiones, sin embargo, puede preceder al sustantivo. Se suele hacer para enfatizar las cualidades del sustantivo. Generalmente, cuando se sitúa el adjetivo delante del sustantivo se suele estar expresando una apreciación subjetiva.
Which really matches the example you are mentioning "yo tengo suficiente ropa" may experss a singular opinion about a topic; you would expect the wife of the person saying this replying "pues yo no" :)