A one-part nutrient is a complete feed supplied as a single product. Liquid one-parts avoid precipitation by using calcium and magnesium nitrates with little or no sulfate, or by leaving out calcium altogether and expecting it from the water or a separate supplement. Dry one-part powders can contain all salts because they only react once dissolved at feeding strength.
In practice
They are convenient: one measurement, less chance of mixing errors. The trade-offs are less flexibility and, for liquids, compromises in the recipe, such as low phosphorus or sulfate, or calcium supplied separately. Read the guaranteed analysis to see what is missing. Dry one-part powders should be dissolved in the full volume of water, not made into a strong stock, or they will precipitate.
Don't confuse with
- A/B nutrient: two concentrates kept separate.
- Base plus additives: a one-part base often still needs supplements in practice.
- Organic all-in-one: slow-release amendments, a different approach.
