Hydroponic Nutrients for Beginners (2026)

In soil, plants draw some of their nutrition from the soil itself. In hydroponics the water is the only source, so the nutrient you mix into it has to be complete: nitrogen, phosphorus and potassium (the N-P-K on the label), plus calcium, magnesium, sulfur and trace elements. That is what a hydroponic “base nutrient” is.

This guide compares three widely used base nutrients from their manufacturers’ labels and product pages, for a first DWC bucket, a countertop system or a small tent. We did not grow with them ourselves; the mixing directions below are the manufacturers’ own.

What to compare

• Complete or not. A hydroponic base has to carry calcium and micronutrients, not just N-P-K. Read the full guaranteed analysis, not only the three headline numbers.
• Number of parts. One-part products are simplest. Multi-part products let you change the balance between growth and flowering, at the cost of more measuring.
• Liquid or dry. Liquids are easy to measure with a syringe or cup. Dry powders are more concentrated, store well and need a scale or the included scoop.
• Directions for your system. Use the brand’s feed chart for hydroponics, not its soil directions.

Label analysis side by side

	GH Flora Series	GH MaxiGro / MaxiBloom	Masterblend 4-18-38 kit
Form	3 liquid concentrates	Dry, one part per stage	Dry, 3 components
N-P-K	FloraGro 2-1-6; FloraMicro 5-0-1; FloraBloom 0-5-4	MaxiGro 10-5-14; MaxiBloom 5-15-14	4-18-38 base, plus Epsom salt and calcium nitrate
Calcium source	FloraMicro (5.0% Ca)	In the powder (MaxiGro 6% Ca)	Calcium nitrate, added last
Mixing order	FloraMicro first, then Gro and/or Bloom	Dissolve fully before any supplements	4-18-38, then Epsom salt, then calcium nitrate
Rates	GH feed charts	Label or Maxi Series feed chart	2.4 g + 1.5 g + 2.4 g per gallon (half rate for seedlings)
pH guidance	5.5–6.5	Commonly 5.5–6.5 for hydro	See Masterblend; target your crop’s range

Figures are from General Hydroponics’ labels and product pages and Masterblend’s product page, checked November 14, 2026.

General Hydroponics Flora Series

The Flora Series is three liquids. FloraMicro (5-0-1) carries nitrogen, potassium, 5.0% calcium and the chelated micronutrients. FloraGro (2-1-6, with 0.5% magnesium) is the growth part, and FloraBloom (0-5-4, with 1.5% magnesium and 1.0% sulfur) is the flowering and fruiting part. General Hydroponics calls this a “building block” system: you change the ratio of the three for seedlings, vegetative growth and flowering.

The labels give the rules that matter. Shake well. Add FloraMicro to fresh water first and stir, then add FloraGro and/or FloraBloom; never combine the concentrates undiluted, which General Hydroponics says can cause nutrient lockout. Keep the solution between pH 5.5 and 6.5, use an EC or ppm meter to control strength, and drain and replace the solution every week or two. Reduce strength if plants show stress or the room is very bright, hot or dry.

General Hydroponics MaxiGro 10-5-14

MaxiGro is a single-part, water-soluble dry concentrate for seedlings, cuttings and vegetative growth. General Hydroponics lists a guaranteed analysis of 10% nitrogen (1.5% ammoniacal, 8.5% nitrate), 5% phosphate, 14% potash, 6% calcium, 2% magnesium, 3% sulfur, and chelated iron and manganese. When plants move into flowering or fruiting, you switch to MaxiBloom (5-15-14).

General Hydroponics’ directions: dissolve completely in fresh water before adding any other supplements, keep the solution below about 75 °F, keep pH in the recommended range (commonly 5.5 to 6.5 for hydroponic and soilless systems), aerate, and refresh the solution on a regular schedule. A scoop is included. For a beginner, one powder per stage is the hardest system to get wrong.

Masterblend 4-18-38 Tomato Formula kit

Masterblend’s 4-18-38 is a water-soluble base that the company says suits soil and hydroponic growing and is ideal for tomatoes, peppers and leafy greens. Its guaranteed analysis lists 4% nitrogen, 18% phosphate, 38% potash, 0.5% magnesium and chelated micronutrients. Its analysis lists no calcium, which is why Masterblend’s mixing table pairs it with Epsom salt (magnesium sulfate) and calcium nitrate.

Masterblend’s mixing table for one gallon of water is 2.4 g of 4-18-38, 1.5 g of magnesium sulfate and 2.4 g of calcium nitrate. Dissolve each completely in that order, with calcium nitrate added last, and use half rates until seedlings are established. Masterblend also says to use the product only after a water quality analysis, so check your tap water first. You will need a small gram scale.

Mixing and managing the reservoir

• Start with clean water and know what is in it. Hard tap water already carries calcium and magnesium.
• Measure exactly. Use the brand’s hydroponic rates, and start at the lower end for young plants.
• Check pH after mixing. University of Missouri Extension gives pH 5.5 to 6.5 as the optimum for most hydroponic crops. Our pH meter guide compares pens.
• Check EC and pH regularly. Virginia Cooperative Extension recommends two to three times a week in DWC.
• Keep the water cool. Colorado State University Extension gives 68–72 °F as the optimum root-zone temperature in hydroponic systems.
• Change the solution every week or two, per General Hydroponics’ Flora labels.

New to hydroponics? Our DWC kit guide covers the simplest system to start with. If you are starting seeds for it, a seedling heat mat helps them germinate in a cool room.

How these picks were made

We picked three widely sold base nutrients that represent the main formats (multi-part liquid, one-part dry, dry kit with separate calcium) and compared them on their published guaranteed analysis and mixing directions. We did not grow with these nutrients ourselves; see how we research.