Last updated: 25 May 2018

I use The Plant List for all my plant nomenclature. You can copy and paste a Latin Plant name such as Arrojadoa dinae into the Search box to see the current status of the name and a listing of synonyms, etc.

Cultivation Notes

Much of my own approach in cultivating cacti is based on that espoused by Dr. Franz Buxbaum in his book CACTUS CULTURE BASED ON BIOLOGY (translated by Vera Higgins), Blandford Press, 1958. He was a pioneer in the use of coarse inorganic growing media to insure superior drainage and root aeration -- acidifying water and soil by testing and modifying the pH -- using complete, balanced fertilizers incorporating micronutrients -- and using non-porous pots in order to maintain healthy root systems.

That is the approach I have used in growing the plants I feature on this site. Please follow your own path in cultivating the plants you grow based on their requirements, your growing environment, your climate, and the type of containers you use


I now grow all of my cacti in plastic pots which, in addition to being light weight, I believe contribute to producing healthy and robust plants.

In addition to their light weight, a great feature of using plastic pots is the ability to easily slide established plants out of their container (and afterward slide them back in) in order to examine the condition and health of the root ball structure (especially checking for the presence of root mealy bugs).

Soil Mix

I have always experimented with soil mixes - I think I have used about every one that has been devised during my growing lifetime - and I have found all those that were of coarse and gritty texture, thus providing excellent drainage and root aeration, consistently produced healthy and robust plants. In consequence I have always used very porous, well aerated, soil mixes for cultivating potted cacti.

I now use a very simple and easy to make soil mix that consists of (mineral component) 60% pumice (+/- ¼"/6.35mm size) and (organic component) 40% bagged coco-peat (coconut coir). On occasion I include up to 5% rice husks as part of the organic component.

Arrojadoa growing in above mix

Top dressing

I have found that water evaporates with alarming rapidity from the soil surface of freshly watered plants in the ferocious sun and heat of our Arizona summers and plants (especially those grown in very small pots) are susceptible to severe dehydration. So I now use a top dressing of native desert gravel for all of my container grown plants.

Watering and Fertilizing

Water: I use Tucson City tap water (which is quite alkaline) exclusively. I check and adjust the pH to ±6.0 using a General Hydroponics GH1514 pH Control Kit.

Fertilizer: I use Algoplus (Algoflash) 5N.7P.5K Cactus Formula liquid fertilizer, which contains magnesium and micro-nutrients, at half the recommended strength at each watering during the growing season.

Watering Regimen

Active growing period (outdoors under 30% shade cloth): With the arrival of warm spring weather I water my plants with increasing frequency. I insure my plants receive copious amounts during the hot Arizona summer months, When I water during this time I do it from above and soak the plants until the water runs freely from the drainage holes. During our Arizona summer "Monsoon" thunderstorm season the frequent (but sporadic) heavy rains (quite acidic in the pH 5.0 to 5.5 range) reduces the hand watering requirements for my container grown plants significantly.

Because these are CAM plants (stomata opening at night) I water at early evening, often every day except for thunderstorm days, during very hot weather here in Tucson, which equates to late May until late September, when the high daytime temperatures are often in the 100°F+ (approx. 38°C+) range (often much higher) with night time temperatures dropping into the 75°F (approx. 24°C) range.

Resting period: These plants do not require a winter cold resting period in order to produce flowers the following spring (that is one reason I favor them). Winter dormancy for them results from the very dry conditions they experience during this time in their habitat. Therefor they only receive occasional light spraying or misting during this time to maintain general plant health.

In essence, I am growing my plants semi-hydroponically using drain-to-waste methodology.