A cactus that is not growing visibly is not automatically hungry. Its species, light, temperature and seasonal activity help determine whether feeding is appropriate.
Check the plant's conditions first. A cactus kept in weak light or a medium that remains wet needs a review of its environment before more nutrients are added.
Separate feeding from watering
Fertiliser instructions assume an appropriate plant and application method. Read the product label, measure the dilution and avoid combining several feeds because each one sounds weak on its own.
If the plant is resting or stressed, do not use fertiliser as a test to see what happens. Record its appearance and check whether growth normally slows under the present conditions.
Different cacti do not share one calendar. A desert species, a tropical forest cactus and an unidentified grafted display may need different decisions. Keep the nursery identification and seek species-specific advice where possible.
When active growth returns, review feeding alongside light and watering. A larger dose does not compensate for a dark position, and a plant that has remained unchanged for a few weeks has not necessarily failed.
Related reading: Cactus Watering and Fertiliser: A Growing Guide.