Fimbristylis aestivalis prefers consistently moist soil. Water regularly, especially during dry spells, ensuring the soil does not completely dry out.

Overwatering should be avoided, but standing water is generally tolerated in its natural wetland habitat. Aim for a consistently damp environment.

Pruning is generally not required for Fimbristylis aestivalis, as it maintains a neat, clumping habit. Remove any dead or damaged foliage at any time of year to maintain aesthetic appeal.

In cooler climates, the plant may benefit from being cut back to a few centimeters above the soil in late winter.

Propagation can be achieved through division of established clumps in spring. Seeds can also be sown in moist conditions in spring or autumn. Scarification of seeds may improve germination rates.

This species readily self-seeds in favorable conditions.

Repotting is typically only necessary if the plant becomes root-bound or if it is being transplanted. This is best done in spring.

If grown in containers, ensure the new pot is only slightly larger than the current one and that the soil remains consistently moist.