Mills Basis B – 20 Liter

Mills Basis B is the B-part of the Mills Nutrients two-part base nutrient system, sold here in the 20-liter commercial size. Formulated with a focus on ingredient bioavailability, it supplies the macro and micronutrients your plants need during both the vegetative and bloom stages. Basis B is designed to pair with Basis A and has been tested in soil, coco coir, and hydroponic systems.

Mills Basis B – 20 Liter Specifications

The following table summarizes the key product specifications for Mills Basis B in the 20-liter size, drawn from supplier documentation and manufacturer labeling.

Specification	Value
Brand	Mills Nutrients
Product Name	Basis B
Volume	20 Liters
Supplier SKU	MILBAB20L
Shipping Weight	~51 lbs (50.9995 lbs)
Growth Stages	Vegetative and Bloom
Compatible Media	Soil, Coco Coir, Hydroponics
Nutrient Type	Macro and Micronutrients (Part B of two-part base)

Why Choose Mills Basis B – 20 Liter

Mills Basis B is part of a two-part base nutrient formula designed with ingredient bioavailability as a primary concern. Here is what distinguishes it from generic nutrient products:

• Bioavailability-focused formulation: Mills formulates Basis B with ingredients selected for how readily plants can absorb and use the nutrients, not just for their presence on a label. This focus helps reduce the risk of nutrient lockout and promotes efficient uptake across the full crop cycle.
• Complete macro and micronutrient profile: Basis B contributes to a broad-spectrum nutrient supply when used with Basis A. Together, the two-part system covers the essential elements plants need from seedling through harvest, eliminating the need for multiple single-element supplements to patch gaps.
• Usable across both growth stages: The formulation is designed for use in both the vegetative and bloom phases. You do not need to switch base nutrient products as your plants transition — the same Basis A and Basis B pair carries you through the entire grow.
• Appropriate for growers at any skill level: Novice growers can follow the manufacturer feed schedule as written and be confident plants are receiving a complete diet. More experienced growers benefit from a stable, predictable base that frees up time for dialing in additives rather than chasing individual deficiencies.
• 20-liter size for commercial and high-volume grows: The 20-liter format is a practical choice for anyone running multiple reservoirs, large recirculating systems, or outdoor plots where making up nutrient solution frequently in small batches is impractical. Buying in this size reduces per-liter cost compared to smaller formats.

Best Uses for Mills Basis B – 20 Liter

Mills Basis B is a versatile base nutrient component well suited to a range of growing environments and crop management styles. The following use cases are directly supported by the product description and testing claims from the manufacturer.

• Recirculating hydroponic systems (DWC, NFT, RDWC): Basis A and B have been tested in hydro environments. The bioavailability focus is particularly relevant in recirculating systems where nutrient solution stability and pH drift matter. Use alongside a calibrated EC meter and pH monitor to stay in range.
• Coco coir grows: Coco coir is a buffered, inert medium that relies entirely on the nutrient solution for plant feeding. Mills Basis B has been specifically tested in coco, making it a straightforward choice for growers running coco in drain-to-waste or recirculating setups.
• Soil and amended media: Basis A and B are compatible with soil grows. In living soil or heavily amended media, the base nutrient rate can typically be dialed back; in lighter mixes, the full feed schedule applies. The product works in both contexts.
• Vegetative stage feeding programs: Growers starting a full Mills nutrient program in veg will use Basis A and B as the foundation, adding stage-appropriate additives on top. The 20-liter size is well matched to growers running long veg cycles or large canopies.
• Bloom stage feeding: Basis A and B continue through the bloom cycle. If you are also running beneficial microbial inoculants during bloom to support root zone health, Basis B provides the mineral foundation those microbes work alongside.
• Commercial and semi-commercial facilities: The 20-liter volume is practical for licensed cultivation facilities, nurseries, and large-scale hobbyist grows where nutrient mixing is a daily or near-daily task. Reduces packaging waste and restocking frequency relative to 1-liter or 1-gallon formats.

Mills Basis B vs Similar Products

Mills Basis B in the 20-liter size is available from multiple authorized distributors. A second authorized distributor lists the same MILBAB20L SKU at $135.00, compared to the $117.00 price here. The product is identical — same SKU, same formulation — so the price difference reflects distributor margin rather than any difference in what you receive.

As a two-part base nutrient, Mills Basis B occupies a similar category position to other premium two-part systems such as General Hydroponics Flora Series or Advanced Nutrients pH Perfect. The distinction Mills draws is the specific emphasis on bioavailability of raw ingredients, which the brand positions as reducing the incidence of nutrient antagonism. Growers already running Mills Basis A have no practical alternative for the B-part — the two are designed as a matched pair and swapping one component for a competitor product is not recommended by the manufacturer.

If you are evaluating whether to start a Mills program versus a different nutrient line, the most relevant comparison is cost per liter of working solution. At the 20-liter scale, Mills Basis B is competitive with other commercial-format two-part concentrates. For growers who want to complement their nutrient program with a carbohydrate supplement during bloom, Mills Basis B pairs with third-party additives without compatibility issues when mixed in the correct order.

Compatibility

Mills Basis B has been tested and confirmed compatible with the following growing media and system types, as stated in manufacturer documentation:

• Soil: Compatible with standard potting mixes and amended soils. Adjust dose rate based on existing nutrient charge in the medium.
• Coco coir: Fully compatible. Coco is one of the primary test environments for the Mills Basis line. Both buffered and unbuffered coco are acceptable, though pre-buffering coco with a calcium-magnesium solution before the first feed is standard practice regardless of base nutrient brand.
• Hydroponics: Compatible with passive hydro (wick, media beds), recirculating systems (DWC, RDWC, NFT), and drain-to-waste drip systems. Target EC range should be matched to the crop and growth stage per the Mills feed schedule.
• Used with Basis A: Basis B is designed to be used in conjunction with Mills Basis A. The two parts together provide the complete base nutrient profile. Do not substitute a competitor’s Part A or Part B — the formulation balance between A and B is specific to the Mills system.

For growers supplementing with microbial products such as biological pest and plant health products, Mills Basis B is a mineral nutrient and does not contain bactericidal or fungicidal agents that would inhibit beneficial microorganisms at standard use rates.

Usage Guidelines

Mills Basis B is a liquid concentrate used as part of the Mills Nutrients two-part base feeding program. The canonical product description does not publish specific milliliter-per-liter dose rates — consult the current Mills Nutrients feed chart (available from your distributor or on the product label) for the precise dose schedule by growth stage and medium type.

General guidance consistent with standard two-part base nutrient practice:

1. Always use Basis A and Basis B together at the ratio specified in the Mills feed chart. The two parts are formulated to complement each other; using one without the other leaves the nutrient solution incomplete.
2. Add to water, not water to concentrate. Start with your reservoir or mixing container filled to the target volume with pH-adjusted water (RO or low-EC source water recommended for hydro and coco).
3. Add Part A first, mix, then add Part B. Never mix A and B together in their concentrated form before adding to water — this can cause nutrient precipitation and binding.
4. Check EC after mixing. Target EC will vary by crop, stage, and medium. Use a calibrated EC/TDS meter to verify the solution is within the appropriate range before watering or adding to a reservoir.
5. Adjust pH after mixing. Two-part nutrient solutions can shift pH after all components are added. Check and adjust to 5.8–6.2 for hydro and coco, or 6.0–6.8 for soil, after all nutrients are dissolved.
6. Shake the bottle before each use. Liquid concentrates can separate during storage. A brief shake or inversion ensures the formula is uniform before measuring.

How to Set Up a Mills Basis Feeding Program

The following steps describe how to integrate Mills Basis B (and Basis A) into a new nutrient program. These steps apply to both first-time Mills users and growers transitioning from another base nutrient line.

1. Obtain both parts. Purchase Mills Basis A and Mills Basis B in a size appropriate for your operation. The 20-liter size is suited to grows requiring regular large-batch mixing.
2. Source the current Mills feed chart. The feed chart specifies dose rates in mL per liter (or per gallon) for each week and growth stage. Obtain it from your distributor or from the product label. Do not rely on third-party or outdated charts.
3. Prepare your water source. For hydro and coco, start with RO or low-EC water (under 0.2 EC). For soil, tap water is generally acceptable if EC and pH are within range.
4. Mix in order: water → Basis A → Basis B → additives → pH adjust. Always add the most concentrated products to water first, one at a time, mixing between additions. Adding additives before pH adjustment lets you make a single pH correction at the end.
5. Measure and record EC and pH. After mixing, verify EC and pH with calibrated meters. Record the values. Consistency across batches helps you detect problems early (e.g., a failed meter, a pump delivering the wrong dose).
6. Introduce to plants gradually when switching from another nutrient line. If your plants have been on a different base nutrient system, transition over one to two feed cycles rather than switching abruptly, to avoid a sudden change in nutrient ratios the root zone has adapted to.
7. Store the concentrate properly. Keep Mills Basis B tightly sealed in a cool, dark location away from direct sunlight and temperature extremes. Do not store near acids or oxidizers.

Sources & Further Reading