Mentha aquatica is easy to grow and can be propagated by seeds or cuttings, although no seeds were used when the author learned the propagation of this plant.

Take stem cuttings and remove the leaves from the lower half of the stem. Place the base of the stems in water and leave to soak. On the 5th day the lateral roots will have grown and the cuttings are ready for planting. Plant the rooted stems in boggy or moist acidic loam soil for the best results. Remember this is a plant that lives in or near the water, thus to grow perfectly it needs water regularly or make sure that the water always enters the container, where you may want to use a cloth connected to both water and the soil. Be careful of overhead watering in warm or humid places it will result in rust.

In seven days, the first new shoots and leaves will have developed. A month later the water mint plant will develop into a nice, matured mint plant. Leaves may then be harvested for cooking or making drinks or for medicinal purposes.

Plant this species in a container, or in the garden where you will not mind it spreading further. This species is suspected to be invasive due to its spreading nature and therefore be cautious when you position it in your garden. Do not plant it where there will be no access to water, it is best to plant it on the edges of a pond, pool, ditch, wet place or waterway. It will make the pond, or the garden looks beautiful and smell as pleasant. Plant it when the temperature is warm to hot in summer for faster results. It grows in full sun exposure and also does well in a little shade. 

Water mint has few pest and disease problems hence it is known as a natural pesticide.

It has a tendency of becoming a ground cover, mulching will not be necessary.