Let’s learn more about SMARTGRO® and see what’s the different between SMARTGRO®  controlled-release fertilizer vs slow-release fertilizer!

What is SMARTGRO®?

SMARTGRO® is comprised of a water-soluble fertilizer encapsulated in a unique polymer coating. The coating allows moisture to penetrate and dissolve the nutrients inside the shell. Dissolved nutrients are slowly released at a constant rate depending on the soil temperature.

SMARTGRO Controlled Release Fertilizer - Smart Fert

Controlled Release Fertilizer – SMARTGRO®

Controlled ReleaseFertilizer vs Slow Release Fertilizer

A common misconception is that Slow Release Fertilizers (SRF) and Controlled Release Fertilizers (CRF) are the same. Both deliver nutrients over a duration but are completely different products. Controlled release fertilizers are only affected by one factor – soil temperature and therefore releases nutrient at a more predictable rate. Controlled release fertilizers only come in a granular form where the coating regulates the nutrient release.

Slow-release fertilizers, on the other hand, is affected by soil temperature, moisture, and pH. Slow-release fertilizers come in granular, nugget or packet/sachet forms where the release mechanism varies widely.

The table below compares the different types of controlled release fertilizer vs slow-release fertilizer on the market.

Comparison of controlled vs slow-release fertilizer

TechnologyPolymer CoatingSulfur CoatingUrea reaction productCompressionNitrification/Urease inhibitors
Release MechanismDiffusionRupture of coatingIBDU: Hydrolisis
MU/UF: Microbial activity
Smaller surface areaInhibition of enzymes
Longevity2-16 months2-3 monthsIBDU: Hydrolisis
MU:12 weeks
UF:12 months
2-4 monthsDepends on soil moisture and bacteria
Release Controlling FactorTemperatureMicrobial activity, moisture, temperatureMicrobial activity, moisture, temperature, pH, organic matterMicrobial activity, moisture, temperature, pHMicrobial activity, moisture, temperature, pH
Controlled Release100%40-50%20-85%30-50%0%

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