What Is Fertigation

Why the feed rides the water

The logic is simple: the roots are where the feed is wanted, and the water already goes there. Broadcasting the fertiliser spreads it over the bed — much of it outside the root zone, much of it lost to the rain and the runoff. The drip line puts the feed at the root zone, in the dissolved form the roots take up, on the schedule the crop's stage wants. The labour moves from the spreading to the tank-mixing, and the feed's efficiency is the point — the fertigation solution page covers it at the system level; this guide covers the method.

The crops that earn it: the long-cycle and the high-value — the tomatoes, the capsicum, the cucumber, the banana blocks, the strawberries, the orchards on the orchard pattern. The feed bill and the season's length are what make the tanks pay; the short, low-feed crops often run the base feeding plus a lighter program.

The setup — the two-tank standard

The standard setup on the Kenyan farm is the two-tank, one-injection-point pattern. The components, in the order they sit on the line:

1. The tanks — two, one for the NPK (the macro feed), one for the micro (the trace elements; a third, the potassium tank, on the fruiting blocks). The size follows the feed's volume per run — the tank holds the mix for the season's runs, not the week's.
2. The injection point — after the filter, before the mainline. The rule is absolute: the feed is never injected before the filter (the undissolved feed is the clog, and the filter is the last clean point). The injection is where the water's pressure and flow carry the feed into the mainline.
3. The injection method — the way the feed gets into the water, matched to the system's pressure and flow. The options, from the simplest:
   • The venturi / the pressure-driven injector. The flow through the venturi creates the suction that draws the feed in — no power, the simplest setup, and the standard on the gravity-fed and the small pump systems. The rate follows the pressure and the flow, and the design guide has the sizing.
   • The dosing pump. The motorised pump that meters the feed in at a set rate — the control is tighter (the rate is set, not followed), and it's the standard on the pump-driven systems where the injection's precision is wanted. The pump page notes the dosing pump as the component.
   • The fertilizer pump / the proportioning unit. The block-scale option — the automatic rate control, the multi-tank program, the automation that runs the feed with the water. The automation guide is the pattern; the commercial guide is where the block-scale setup is standard.
4. The flush line — the line that runs the plain water after the feed, clearing the tank and the injection line. The flush after each feed is the rule that keeps the precipitate out of the drip lines — the line cleaning guide covers the failure it prevents.

The filtration is the fertigation's partner — the feed's undissolved residue is the clog that the filter is the last line against, and the filter's routine tightens when the feed is in the system. The two guides read together.

The program — the feed follows the crop

The program is the feed's schedule: what's in the tank, at what rate, in which stage of the crop's cycle. The structure, on the standard two-tank setup:

• Establishment. The light feed — the roots are setting, and the program is the gentle start. The NPK tank at the low rate, the micro held back.
• Vegetative growth. The nitrogen-heavy window — the NPK tank at the growth rate, the feed riding the water's daily runs. The crop's green growth is the program's work.
• Flowering → fruit set. The shift — the phosphorus and the potassium carry the set, the nitrogen eased. The tomato and capsicum pages note the window; the program is where the shift is made.
• Fruiting / filling. The potassium-heavy window — the fruit's fill and the quality track the supply. The third tank (the potassium) is the fruiting blocks' line, and the rate follows the crop's peak.
• Late season. The ease-off — the feed tapers as the crop winds down, and the flush routine keeps the system clean for the rest.

The rates are the agronomy's — the crop's feed plan sets what's in the tank, and the drip is the delivery. The crop pages note the fertigation's role per crop; the fertigation solution page is the system-level view. The assessment is where the program is built from the crop plan and the water.

The safety rules — the ones that save the system

The rules are short, and they're the ones that prevent the clog and the crop loss:

• Never two incompatible feeds at once. The two tanks run separately, the line flushed between — the precipitate (the two feeds reacting in the line) is the clog that the flush prevents. The compatibility chart is the reference; the rule is the habit.
• Always dissolve before you inject. The undissolved feed is the clog, and the tank's mix is where the dissolving happens — the feed added to the water, stirred, and only the clear mix injected. The filter is the last clean point, not the dissolver.
• Always flush after the feed. The plain water after each feed clears the tank and the injection line — the flush line's whole job, and the maintenance routine that keeps the system clean.
• Never inject at the high-pressure end. The injection is where the pressure and the flow carry the feed in — the design guide has the injection point's position, and the upgrade adds the point where it's missing.

Fertigation vs broadcast — the honest comparison

Next, in the guides