Controlled-release fertilizer.

A fertilizer, usually resin- or polymer-coated granules, that releases nutrients gradually as water diffuses through the coating at a rate set mainly by temperature.

What it means for your plants

Label durations such as 3–4, 6 or 8–9 months are calculated at about 21 °C; release is faster in warm rooms and slower in cool ones. Record the date and rate, and do not add full-strength liquid feed on top.

Put it into practice

Liquid feed gives precise control; coated slow-release prills feed for 3–9 months but speed up in warm rooms. How each works, when to use it, and why not to stack them.