Growth Science Base B – Gal

Growth Science Base B (0-6-4) is the phosphorus and potassium half of a streamlined two-part base nutrient system designed for growers who want clean, efficient feeding across every stage — from clones and seedlings through late bloom — in soil, coco coir, or any hydroponic medium.

Growth Science Base B Specifications

Growth Science Base B is a liquid concentrate formulated to deliver phosphorus, potassium, magnesium, and sulfur directly to the root zone. It carries an NPK of 0-6-4 and is used at equal or higher rates than its companion Base A depending on growth stage. The product ships in a 1-gallon (128 fl oz) HDPE bottle and is compatible with fertilizer injectors, making it well-suited for commercial operations and scaled gardens alike.

Specification	Value
NPK Analysis	0-6-4
Primary Nutrients	Phosphorus (P), Potassium (K), Magnesium (Mg), Sulfur (S)
Size / Volume	1 gallon (128 fl oz) liquid concentrate
Weight	11.0011 lb
Form	Liquid concentrate
Compatible Media	Soil, coco coir, all hydroponic mediums
Fertilizer Injector Compatible	Yes
Growth Stages	All stages: clones/seedlings through late bloom
Partner Product	Growth Science Base A (NPK 5.5-0-0)
Available Sizes	Quart, 1 gal, 2.5 gal, 5 gal, 55 gal, 275 gal
Brand	Growth Science Nutrients (distributed by Hydrofarm)
SKU	GSCBBG

Why Choose Growth Science Base B

Growth Science was built around one core idea: give plants what they need, without unnecessary complexity. Base B reflects that philosophy directly. Rather than requiring growers to juggle three or four base bottles, the entire macro-nutrient foundation is split into just two parts — Base A handles nitrogen and calcium; Base B handles phosphorus, potassium, magnesium, and sulfur. Every element has a defined role, nothing is redundant.

• Two-part simplicity with full-spectrum macro coverage. Base B (0-6-4) pairs with Base A (5.5-0-0) to deliver a complete base nutrient profile with only two bottles to manage. Compared to three-part systems that require separate bloom, micro, and grow bottles, this approach reduces measuring steps and mixing errors per feeding.
• Fertilizer injector compatible. The concentrate is formulated to work with standard fertilizer injectors, which matters for commercial greenhouses, large-scale hydroponic operations, and any grower running automated irrigation. Many hobby-grade nutrients are not injector-safe due to precipitation risk at high concentrations.
• Single-formula across all growth stages. The same Base B bottle is used from clone/seedling through late bloom; only the dose rate changes. This reduces the need for multiple SKUs and simplifies inventory for both home growers and commercial operations.
• Universal media compatibility. Base B is designed for soil, coco coir, deep water culture, ebb-and-flow, NFT, and all other common hydroponic mediums. Growers switching between media types do not need a different product.
• Distributed by Hydrofarm, founded 1977. Hydrofarm is one of the longest-established distributors in the controlled-environment agriculture industry, providing supply chain reliability and consistent product availability across retail and wholesale channels.

Best Uses for Growth Science Base B

Base B is a broadly applicable base nutrient, but the following use cases represent where growers get the most value out of its formulation and injector compatibility.

• Hydroponic reservoirs (DWC, ebb-and-flow, NFT, drip). The liquid concentrate mixes cleanly into reservoir water. Use alongside Base A at equal ratios during veg, then increase Base B relative to Base A during bloom stages per the feeding chart below.
• Coco coir grows. Coco coir is naturally low in phosphorus and potassium and requires supplementation from the start. Base B’s 0-6-4 profile pairs well with the calcium and nitrogen provided by Base A to create a balanced coco feeding program.
• Soil grows requiring bloom support. During the bloom phase in soil, phosphorus demand increases sharply. Increasing Base B to 10 ml/gal (while keeping Base A at 5 ml/gal) according to the feeding schedule provides that additional P and K without switching products.
• Commercial operations with fertilizer injectors. The injector compatibility of Base B makes it practical for greenhouse and large-scale indoor grows where hand-mixing individual reservoir batches is not feasible. The concentrate can be proportioned directly through injection systems.
• Growers building a Growth Science nutrient stack. Base B anchors one side of the two-part system. From there, growers can add Growth Science Base A (gallon) as the companion part, and supplement with Solid Start (kelp veg booster), Rock Solid (bloom booster), or Strength (silica) as needed for their specific crop and goals.
• Multi-stage programs needing a single SKU. Because dosing rates simply adjust by stage rather than requiring product swaps, Base B is well suited to operations that want to minimize SKU count while maintaining stage-appropriate nutrient ratios.

Growth Science Base B vs General Hydroponics Flora Series

The General Hydroponics Flora Series is the most widely referenced three-part base nutrient system in indoor growing. It consists of FloraGro, FloraMicro, and FloraBloom, each targeting a different nutrient cluster. The system is well-established and has a large body of published feed charts behind it. However, it requires growers to measure, mix, and adjust three separate concentrates per feeding session, and published feed charts often call for different ratios of all three parts at different stages — creating meaningful complexity for anyone managing multiple plant varieties or reservoir sizes simultaneously.

Growth Science Base A and Base B reduce that to two parts. During vegetative growth, both are used at equal rates. During bloom, Base B is increased relative to Base A to shift the phosphorus and potassium ratio upward, which is accomplished by changing a single number in the feed chart rather than adjusting three separate inputs. For operations running fertilizer injectors, the two-part architecture also simplifies injector station configuration: two injector heads instead of three or more. The Flora Series does have an advantage in that it has been extensively documented by hobbyists over many years, and third-party calculator tools for it are widely available. Growers who are already experienced with the Flora Series and comfortable with the three-part approach do not necessarily gain efficiency by switching. For growers starting fresh or scaling to commercial infrastructure, the simplicity of the two-part Growth Science system is a tangible operational benefit.

Compatibility & Operating Range

Growth Science Base B is compatible with all common growing media including soil, coco coir, perlite, rockwool, clay pebbles (LECA), and all standard hydroponic systems (deep water culture, ebb-and-flow, nutrient film technique, aeroponics, and drip irrigation). The concentrate is suitable for use through standard fertilizer injectors, making it appropriate for professional greenhouse applications and commercial indoor growing facilities.

pH target range: For hydroponic systems, target a reservoir pH of 5.5–6.2 after adding all nutrients. For soil and coco coir, a slightly higher pH of 6.0–6.8 is typical. Base B should be added to water that has been pH-adjusted to your base target, then check and adjust final pH after all nutrients are mixed.

EC / TDS considerations: Base B contributes to the overall EC of your nutrient solution. At typical bloom rates of 10 ml/gal for Base B and 5 ml/gal for Base A, combined EC will vary depending on your starting water quality (RO vs tap). Always check EC with a calibrated meter before feeding. Growth Science does not publish absolute EC targets for each stage, so rely on your own runoff readings and plant response to dial in EC over time.

Companion products: Base B is designed to work within the Growth Science Nutrients ecosystem. The full lineup of compatible supplements includes:

• Base A (5.5-0-0) — nitrogen, calcium, and micronutrients; the required companion part
• Solid Start (2-0-6) — cold-pressed kelp veg booster; recommended during vegetative growth
• Rock Solid (0-4-4.5) — bloom booster; used alongside Base B for additional P/K push during peak flowering
• Strength (0-0-1) — silica supplement; compatible across all stages

Base B is not known to be incompatible with standard pH adjusters (pH up/down), beneficial microorganism products, or silica supplements, but as with any nutrient program, mix nutrients individually into water one at a time rather than combining concentrates directly. Avoid mixing Base A and Base B concentrates together before diluting in water, as high-concentration mixing of certain ions can cause precipitation.

Dosing Guidelines

Growth Science publishes a straightforward six-stage feeding chart for Base A and Base B. The notable feature of this chart is that Base B holds equal or higher rates than Base A throughout the program, and increases to 10 ml/gal during bloom and late bloom while Base A stays at 5 ml/gal. This shift reflects the increased phosphorus and potassium demand plants have once they enter reproductive growth. All rates below are per gallon of water.

Growth Stage	Base A (ml/gal)	Base B (ml/gal)
Clones / Seedlings	3	3
Mild Vegetative	5	5
Aggressive Vegetative	6	6
Transition	5	5
Bloom	5	10
Late Bloom	5	10

Notes on applying the feeding chart:

• Start at the lower end of the range when introducing a new strain or working with young plants that have not yet developed a full root system. Young roots are more sensitive to salt buildup, so the 3 ml/gal clone/seedling rate provides nutrients without overwhelming undeveloped feeder roots.
• Transition stage dosing reflects the period when plants shift from vegetative to reproductive growth. Dropping from 6/6 back to 5/5 during transition gives plants time to adjust their metabolism before Base B is doubled in the bloom phase. Some growers extend the transition rate for an additional week if plants are still showing primarily vegetative characteristics.
• The 10 ml/gal Base B rate during bloom and late bloom is a 2x increase over the Base A rate for those stages. This elevated P/K delivery supports root-to-flower energy translocation, enzyme activation (potassium), and early fruit/seed set processes (phosphorus) during the reproductive phase.
• Monitor runoff EC. At the 10 ml/gal rate, Base B combined with Base A at 5 ml/gal contributes meaningful salt loading to the root zone. In closed-loop hydroponic systems, test reservoir EC before each top-off or reservoir change. In coco coir or soil, monitor runoff EC at least once weekly and flush if runoff EC exceeds input EC by more than 0.5–1.0 mS/cm.
• Adjust for water quality. Growers using reverse osmosis (RO) water will start from a near-zero baseline EC and can use the published rates as written. Growers using tap water with significant baseline EC (above 0.3 mS/cm) should reduce nutrient dose slightly or flush more frequently to prevent salt accumulation.
• Shake well before use. As with most liquid nutrient concentrates, settling can occur during storage. Shake or swirl the bottle thoroughly before measuring each dose to ensure consistent nutrient distribution throughout the concentrate.

A 1-gallon bottle of Base B at the published bloom rate of 10 ml/gal yields approximately 473 gallons of nutrient solution (3,785 ml per gallon ÷ 8 ml average across all stages). At the strictly bloom rate of 10 ml/gal, one gallon of concentrate makes approximately 379 feedings of one gallon each. For larger reservoir systems, the Growth Science Base B in quart size is a cost-effective option to evaluate the product before committing to the gallon or larger drum sizes.

How to Set Up Growth Science Base B

The following steps apply to any growing medium. For reservoir-based hydroponic systems, “feeding water” refers to the reservoir; for soil and coco coir, it refers to the irrigation water prepared for each watering event.

1. Gather your equipment. You will need a calibrated syringe or measuring cup, a pH meter, an EC/TDS meter, a mixing container (or reservoir), and pH adjustment solution (pH up/down). Use separate syringes or rinse thoroughly between Base A and Base B to avoid concentrate cross-contamination.
2. Start with clean water. Fill your reservoir or mixing container with water at your target temperature (ideally 65–72°F / 18–22°C). If using RO water, verify starting EC is below 0.1 mS/cm. If using tap water, note the baseline EC before adding any nutrients.
3. Shake the concentrate. Shake the Base B bottle well before measuring. Pour concentrates into the bottle cap or a separate measuring vessel before adding to your water — do not pour directly from bottle to bottle.
4. Add Base A first, then Base B. Add Base A to the water at the recommended ml/gal rate for the current growth stage, then stir. Add Base B separately at its recommended rate and stir again. Adding each part individually into already-moving water reduces the risk of localized precipitation where concentrated solutions contact each other before diluting.
5. Add any supplemental products. If using Solid Start, Rock Solid, Strength, or other supplements, add them after both base parts have been stirred in. Follow each supplement’s recommended dose rate.
6. Check and adjust pH. After all nutrients are mixed, test pH with a calibrated meter. Adjust to 5.5–6.2 for hydroponic systems or 6.0–6.8 for soil/coco. Add pH up or pH down in small increments, stirring between additions, until the target is reached.
7. Verify EC. Check EC against your target range for the growth stage. If EC is higher than desired, dilute with additional plain water and recheck. If lower, increase dose by a small increment.
8. Feed plants or fill reservoir. Deliver the prepared solution to your plants immediately or use it within 24–48 hours. Do not store prepared nutrient solution for extended periods, as pH drift and microbial activity can degrade solution quality, particularly in aerated reservoirs.
9. Monitor and adjust over time. During the first one to two weeks with a new feeding program, observe leaf color, tip burn (a sign of over-fertilization), or yellowing (a possible sign of under-fertilization or pH lockout). Dial in dosing based on plant response rather than mechanically following the chart without observation.

Sources & Further Reading