Nutrient Mixing¶

A correctly mixed nutrient solution is the foundation for healthy plant growth. Kamerplanter automatically calculates EC budgets, scales manufacturer recipes, and validates the mixing order — preventing precipitation and wasted nutrients.

Two terms up front: Fertigation and Drain-to-Waste

Fertigation ("Fertilizer" + "Irrigation") means automated delivery of nutrient solution through irrigation — usually via a drip system and pump, instead of watering by hand with a can. In Kamerplanter, fertigation is one of the delivery methods alongside drench, foliar, and top-dress.

Drain-to-Waste is an irrigation strategy without recirculation. You deliberately water with a surplus (usually 10–30 % more than the substrate can hold), so runoff water drains from the bottom of the pot. This runoff is discarded rather than reused — unlike recirculating systems such as NFT (Nutrient Film Technique) or ebb & flow. The advantage: salt buildup in the substrate is prevented, because excess nutrients are flushed out rather than reused. More on this in the Runoff Analysis section below.

Mixing order matters

Always add CalMag (calcium-magnesium supplement) first to the water before adding any other fertilizer — especially before sulfates and phosphates. Wrong order causes calcium sulfate precipitation (CaSO₄) and renders the solution ineffective.

Prerequisites¶

EC meter (electrical conductivity meter)
pH meter or test kit
Known EC values for your water source (tap water or RO water)
Fertilizers added in Kamerplanter under Fertilization → Fertilizers

The EC Budget Model¶

Kamerplanter calculates how much electrical conductivity the fertilizers may still contribute — the EC budget:

EC_net = EC_target - EC_base_water

Variable	Meaning	Example
`EC_target`	Desired final EC of the nutrient solution	1.8 mS/cm
`EC_base_water`	EC of the water used	0.4 mS/cm
`EC_net`	Remaining budget for fertilizers	1.4 mS/cm

RO water for maximum control

Reverse osmosis (RO) water typically has EC < 0.05 mS/cm, freeing the full EC budget for nutrients. Hard tap water with high Ca/Mg content significantly reduces the available budget.

The 3-Stage EC Budget Pipeline¶

Kamerplanter applies a structured 3-stage calculation:

Stage 1 — Water Mix (EC_mix)¶

When blending RO and tap water, Kamerplanter first calculates the EC of the blend:

EC_mix = EC_tap × (1 - RO_fraction) + EC_RO × RO_fraction

Example: 50 % RO (EC 0.02) + 50 % tap water (EC 0.50):

EC_mix = 0.50 × 0.50 + 0.02 × 0.50 = 0.26 mS/cm

Stage 2 — EC Allocation (Budget Segments)¶

The net EC budget is divided into segments in this order:

Segment	Priority	Description
Silica	1 (first deduction)	Optional silicate is pre-calculated
CalMag	2	Calcium-magnesium solution (essential for coco/hydro)
pH Reserve	3	Buffer for pH adjuster (0.02–0.05 mS depending on water hardness)
Base Nutrients	4	Remaining budget distributed to base nutrients

Where to find these values in the nutrient calculator

In the mixing protocol (Fertilization → Nutrient Calculations → Mixing Protocol) you enter your water's carbonate hardness as alkalinity (ppm CaCO₃). Kamerplanter automatically calculates the pH reserve from it and shows it together with the net EC budget (ec_net) and the recipe's validity (valid) in the result. Details on how to use it: Fertilization — Alkalinity and pH Reserve.

Stage 3 — Recipe Scaling¶

When manufacturer recipes (ml/L per fertilizer) are stored in Kamerplanter, the system scales proportionally:

k = EC_net / EC_full_recipe
dose_i = k × recipe_dose_i

Without recipe data: the EC budget is distributed equally across all base fertilizers.

Mixing Order — Step by Step¶

The mixing sequence is critical. Kamerplanter automatically generates a numbered mixing guide:

1. Fill container with [X] liters of water
2. Add silica — stir vigorously, wait 5 minutes
3. Add CalMag — mix thoroughly
4. Add base nutrient A — stir
5. Add base nutrient B — stir
6. Adjust pH to target — stir, wait 5 minutes
7. Verify final EC reading

Why silica before CalMag?

Silicate ions (SiO₄²⁻) form poorly soluble calcium silicate (CaSiO₃) with calcium ions (Ca²⁺). Therefore silica must go into the water before CalMag — otherwise the active ingredient precipitates out.

Incompatibilities and Safety Validation¶

Kamerplanter automatically checks the following combinations:

Combination	Risk	Severity
CalMag + Sulfates (e.g. Epsom)	Gypsum precipitation (CaSO₄)	Critical
CalMag + Phosphates	Calcium phosphate precipitation	Critical
Silica + CalMag (wrong order)	CaSiO₃ precipitation	Critical
Iron chelate + pH > 7	Chelate destabilizes	Warning
Foliar-only + fertigation products	Wrong application method	Note

Act on critical warnings immediately

If a red warning appears in the mixing guide, stop immediately and check the fertilizer combination. A precipitated solution cannot be recovered — complete remixing is required.

EC Target Values by Phase and Substrate¶

Kamerplanter validates the calculated final EC against phase- and substrate-specific maximum values:

Substrate	Seedling (mS)	Vegetative (mS)	Flowering (mS)	Flushing (mS)
Hydroponics	0.8 – 1.2	1.6 – 2.4	1.8 – 2.8	0.0 – 0.3
Coco	0.8 – 1.0	1.6 – 2.0	1.8 – 2.4	0.0 – 0.3
Soil	0.4 – 0.6	0.8 – 1.4	1.0 – 1.6	0.0 – 0.3

Fresh coco: automatic CalMag boost

For freshly set-up coco batches (0 cycles used), Kamerplanter automatically increases the CalMag dose by 20 %, since unused coco absorbs calcium and magnesium from the solution (cation exchange).

Flush and Rest Phases: Automatically No Feed¶

In addition to the table above, Kamerplanter automatically applies a fixed rule for two phases: for flushing and dormancy (winter rest), the phase's nutrient profile is always 0:0:0 (no feed) — regardless of any recipe otherwise stored. The phase's nutrient view (see Growth Phases) shows the chip "No feed (flush / rest phase)" for this. For your mixing routine, this means: in these phases there is nothing to mix — you water with plain water only.

Kamerplanter also checks each phase's target pH for micronutrient availability: if the target pH falls outside the optimal window of pH 6.0–6.5, iron, manganese, zinc, copper, and boron increasingly lock out of uptake (chlorosis risk — pale, yellowish leaf veins). Kamerplanter shows this warning as "Micronutrients locked out (pH lockout)" in the phase's nutrient view.

EC Temperature Correction (EC@25)¶

The electrical conductivity of a reading depends on water temperature — the same nutrient solution shows a higher EC in warmer water than in cooler water. To keep measurements taken at different temperatures comparable, Kamerplanter can optionally correct to the 25 °C reference temperature:

EC@25 = EC_measured / (1 + 0.02 × (T − 25))

If you enter both your measured EC value and the water temperature in the EC Budget Calculator, Kamerplanter automatically computes this corrected value and shows it in addition to the raw reading.

Example

You measure 1.9 mS/cm at a water temperature of 30 °C. Corrected to 25 °C: EC@25 = 1.9 / (1 + 0.02 × 5) = 1.9 / 1.1 ≈ 1.73 mS/cm. The uncorrected value would make the nutrient solution look stronger than it actually is at the reference temperature.

Setting pH¶

After mixing all nutrients, measure and correct the pH:

Substrate	Target pH Range	Note
Hydroponics	5.5 – 6.0	Optimum nutrient availability
Coco	5.8 – 6.2	Slightly higher than hydro
Soil	6.0 – 6.8	Consider microbial activity
Living Soil	6.2 – 7.0	pH buffered by soil biology

Kamerplanter instructs whether pH Up (potassium hydroxide) or pH Down (phosphoric acid) is needed.

Always adjust pH last

pH corrections must be performed as the final step — after all nutrients have been mixed in. Nutrients change the pH and may require a second adjustment.

Runoff Analysis¶

In drain-to-waste operation (coco, rockwool), runoff analysis provides important feedback:

Measurement	Target Range	Deviation → Action
Runoff EC − Input EC	±0.3 mS/cm	> +0.5: salt buildup → flush
Runoff pH − Input pH	±0.5	> ±0.5: check substrate buffering
Runoff volume / Input	10 – 30 %	< 10 %: increase water volume

Typical flush signal

Runoff EC = 2.8 mS, input EC = 2.0 mS → delta = +0.8 mS (exceeds threshold of 0.5). Kamerplanter recommends 1–2 flush cycles with clean water (EC < 0.3 mS, pH 6.0).

Pre-Harvest Flushing¶

Kamerplanter automatically calculates a flushing schedule via the Flushing Calculator. Recommended flush duration depends on substrate:

Substrate	Recommended Flush Duration
Hydroponics	7 – 14 days
Coco	10 – 21 days
Rockwool	7 – 14 days
Soil	14 – 30 days

Flushing protocol (3-phase reduction):

Time segment (% of flush period)	Target EC	Action
First 30 %	50 % of original EC	Reduced nutrient solution
Middle 30 %	25 % of original EC	Quarter-strength
Final 40 %	0.0 mS/cm	Plain water only

Water Temperature¶

Water temperature affects solubility and biological effectiveness:

Temperature	Assessment
< 5 °C	Too cold — poor dissolution, precipitation risk
5 – 18 °C	Suboptimal — stir longer
18 – 22 °C	Optimal
22 – 30 °C	Acceptable — biological products may degrade faster
> 35 °C	Not suitable for biological fertilizers

Frequently Asked Questions¶

My solution is white / cloudy after mixing — what happened?

Cloudiness indicates precipitation. Most common cause: CalMag was added after a sulfate or phosphate. Discard the solution, rinse the container with warm water, correct the mixing order, and start fresh.

Can I add all fertilizers at the same time?

No. CalMag and sulfate/phosphate must not come into contact simultaneously — this immediately causes precipitation. Always add step by step and stir between additions.

How often should I measure EC and pH of the finished solution?

Always immediately after mixing. For tank/reservoir systems, check daily — EC rises as water evaporates and pH drifts due to plant metabolism.

What does 'not tank-safe' mean for a fertilizer?

Fertilizers that are not tank-safe must not be stored in a reservoir over extended periods — they decompose or precipitate. They must be mixed fresh before each application.