Nutrient escapes through a polymer or resin coating gradually rather than dissolving at once.

Coating thickness and formulation determine how long that takes.

Most coatings release faster as temperature rises.

That happens to match plant demand, since grass grows fastest when it is warm.

It also means a cold spring delays release and a hot spell accelerates it.

Stated longevity is therefore an approximation rather than a guarantee.

Even growth, much lower scorch risk, reduced leaching and fewer applications.

Soluble feeds produce a surge of growth followed by a fade; controlled release does not.

That means less clipping volume and fewer mowing peaks.

Because nutrient is not sitting on the surface in soluble form, burn risk is very low.

Leaching is reduced substantially, which matters near water and where run-off is regulated.

One application replacing three or four is a large labour saving on any significant area.

Per bag yes, sometimes considerably - per season with labour included, usually much less so.

The up-front figure is what people compare, and it is the least useful comparison.

Three or four applications of a cheaper product cost three or four lots of labour.

On sites where access is difficult or disruptive, fewer visits may be the deciding factor.

Reduced waste from leaching is a real if less visible saving.

For a small domestic lawn the labour argument carries less weight and the bag price dominates.

Spreading equipment that cracks the prills, and aggressive incorporation into soil.

A cracked coating releases the entire nutrient load at once.

That produces exactly the scorch the product exists to avoid.

Some spreaders are harsher on prills than others.

Rotary cultivation of a coated product into soil is a common way to ruin it.

Handling gently and surface-applying is what the product is designed for.

It releases slowly in cold conditions, which is usually correct but occasionally not.

Slow release matches slow growth, so the matching is normally helpful.

A prolonged cold spring can delay release past when a visible response was wanted.

Where a fast response is needed, a liquid feed alongside is the usual answer.

Some products combine a quick-release fraction with a coated one for exactly this reason.

Reading the release profile rather than just the stated duration is worthwhile.

Large areas, difficult access, sites near water, and anywhere consistent growth matters.

Sports turf and amenity areas benefit from even growth rates.

Sites near watercourses benefit from reduced leaching.

Roof gardens, planters and containers use it because repeat feeding is impractical.

Nursery and landscape planting uses it to cover an establishment season.

For a small lawn fed twice a year by hand, the argument is much weaker.

Physically yes, but blending changes the release profile and is not usually worthwhile.

Blended products containing both coated and uncoated fractions are sold for that purpose.

Mixing on site produces an uneven distribution of the two types.

Combination products with herbicides are less common in coated form.

Applying a separate liquid feed alongside is the more controllable approach.

Where a specific programme is wanted, a manufacturer's blend is more reliable than an improvised one.