Mammillaria Hahniana “Old Lady Cactus” Care & Buying Guide

Mammillaria Hahniana


Light requirementsHigh
Water requirementsLow
Ease of careEasy
Zone9a to 10b
Temperature resistanceMildly frost-hardy
Growth speedSlow
Indoor growingSuitable


Taking Care Of Mammillaria Hahniana “Old Lady Cactus”

Ideal conditions

Outdoors is where Mammillaria Hahniana “Old Lady Cactus” truly thrives, even though it can be successfully grown inside as well. The Old Lady Cactus favors partial to full sun and warm temperatures. It’s somewhat frost-hardy (can survive in temperatures as low as 20 F/-6.6 C), but it shouldn’t be left outside for a long time if it’s cold.


Water the Old Lady Cactus only when its soil gets dry to the touch. This cactus is drought-resistant and requires little water to thrive. Take care not to overwater the Old Lady Cactus – like many other cacti, this plant doesn’t like standing water and can easily catch root rot if exposed to excessive amounts of water.

In winter, cut back on the water supply – the Old Lady Cactus will be dormant and will not require as much water as usual. Either do not water the cactus at all, or mist it occasionally if you feel like it. But don’t overwater the plant – in winter, it gets much more sensitive to standing water and is much more susceptible to root rot.

Where to plant

The Old Lady Cactus should be planted in a fast-draining cactus mix, preferably with added pumice or perlite for enhanced draining. If planting the cactus in a pot, make sure to pick an easy-draining pot with large drainage holes.

The Old Lady Cactus is best to be kept outdoors due to its high light needs. Partial to full sun is what this cactus prefers, and it will not do well if kept in a shaded location for too long.

Only move the cactus to a shaded location during a heatwave or intense heat. Though the Old Lady Cactus is fairly resistant to heat, extreme temperatures are likely to cause sunburn.

The Old Lady Cactus may be kept indoors as well, but only if you have a spot near a window that’s lit all day. If sunlight is inadequate in your area, then you may place the cactus under grow lights, but do remember that natural sunlight is a must.

If winters in your area get cold, then be sure to move the cactus inside.

General care information

Fertilize the Old Lady Cactus at least once in the summer months with a high-potassium fertilizer. Depending on your fertilizer, you may fertilize the cactus a little more often, but do not overdo it – if the plant grows faster than the roots, the roots won’t be able to supply adequate nutrition to the plant.

Repot the Old Lady Cactus as well, preferably at least once every year during late spring or summer. Repotting is necessary because the cactus will sooner or later outgrow its pot, and it also allows you to check the health of the cactus’ roots.