DISCOCACTUS

Growth & Care Needs

I acquired my two Discocactus late in 2020, and they looked as you can see above. They were in 5″ pots, from a wholesaler who I know pots with a generous mix of pumice and cactus soil, so they were set for a while.

What I had read about their care implied that they needed somewhat consistent water, and to be protected from temperature extremes. Picking them up near the end of the year meant I was immediately throwing them into the riskiest time of year for our area: winter!

Temperature preferences for Discocactus  You should keep these above freezing at a bare minimum, and they greatly prefer being much warmer than that. Recommendations online say to keep them above 60F; mine routinely experienced lows in the 30s during the coldest time of winter. I kept them on the dry side if I knew cold weather was coming, and would lightly water them if we had a warmer day (70s+).

Using even a plastic greenhouse is likely what made a significant difference in my experience growing these during periods that were definitely too cold for common internet recommendations. My little cheap greenhouse allowed them to get up to the 80s on sunny winter days, with occasional days in the 90s! At night, the greenhouse plus location (close to the house, sheltered from actually hitting freezing) kept them just warm enough to not suffer.

In summer, they do absolutely fine with extreme highs: temperatures of 110F+ in my greenhouse didn’t even phase them. I did make sure they had time to acclimate to the conditions in the new greenhouse – which was about a week or so in more shaded conditions, provided with plentiful water in the evenings.

Watering, Light, and Soil

Water, light, and soil are all tightly intertwined and really can’t be spoken of independently. In the photos above, the two Discocactus have come through the coldest winter temperatures and are showing signs of new growth in early spring (April 2021). The cactus at right had more exposure to light and cold, and blushed a purplish shade.

With Discocactus, it seems that their roots are relatively delicate, and they are not fans of being repotted. As a result, I didn’t repot mine for nearly all of the initial time I had them (also why I haven’t blogged about their care – does it count if I didn’t repot in my own soil?).

When it’s warm and they have plenty of light, they’ll take a regular amount of water. In colder months, I’d water them once every week or two if daytime highs in their greenhouse averaged over 75F. The main reason for this was related to nighttime temperatures – they needed to be kept from getting too dry, but they also couldn’t be too wet. In winter, I tried to water lightly: the water barely flowed out of the bottom of the pot or didn’t flow out at all.

Once the weather warmed up, those bets were off. All through spring and into summer, I would water every few days, usually checking if it was needed by picking up their pots to look underneath or feel the weight. If the pot felt light or it looked dry underneath, I’d water the cacti thoroughly. In warmer months, I made sure to saturate the soil and see water streaming out of the drainage holes below.