You should say "water" instead of "the water" as Kenny suggested, unless there's a specific source of water that must be used to grow plants (which we know isn't true, any water will do; however it could be possible for specific plants, in which case you'd also say "the plants"). No other articles can be omitted. "Growth" is uncountable and in certain contexts doesn't need an article, but in your sentence it can only be definite.

Although (the) water is critical to the growth of plants, the amount of water actually delivered to the root system is almost as important ( ) > delete