Best Potting Mix Soil for Ponytail Palm Tree Repotting

Question:

I live in Mexico City, and have a BEAUTIFUL 10 year old pony tail palm which is doing great. I have it near a West facing window, it is about 5.5 ft tall, and water it with 1/4 to 1/2 gallons weekly depending if its summer or winter, I also fertilize monthly.  I need to repot it just because the fiber glass container is a little bit small (1.80 feet diameter – 55 cm.) and it has cracked. I designed and fabricated a beautiful new fiberglass container (2.2 feet diameter – 65 cm),  no drainage holes as the last one, CANT HAVE THEM!

I am putting10 cm lava rock in the base, then a kind of cheap pillow case fill material, which is about  1cm thick, then the soil should go in and the ponytail palm.

What kind of soil should I use, I need a commercial name, please, no good just to get info on “well draining, large particle, perlite, etc…” The soil it has now is the one it came with, originally, ten years ago, and it seems just very regular soil.

I already bought the MIRACLE GROW MOISTURE CONTROL POTTING MIX but now I am afraid it might not be the best. I´ve read infinite information and now do not know what to do.

Basically.

1. Is MIRACLE GROW MOISTURE CONTROL POTTING MIX right?
2. Should I instead buy some kind of CACTI MIX, I haven´t found a commercial one.

Should I mix half MIRACLE GRO MOISTURE CONTROL and half regular container potting mis.

4. Should I mix Half MIRACLE GRO MOISTURE CONTROL and green house non commercial bought cacti mix.

Answer:

Your Question: is about the best potting mix for your Ponytail Palm, so I will address that first. Then I will offer some unsolicited advice based on many years of professional maintenance of Ponytail Palms like yours.

The best brand name potting mixes are Pro-Mix by Premier and specifically, I would recommend their Cactus mix for you. I have no idea if it is available to you, but you did ask for a specific commercial name.

I do NOT recommend Miracle-Gro moisture control, which seems to have a near-monopoly on the market. The moisture control is misleading because it implies that it holds and releases just the right amount of water. In fact, it means they have added moisture RETAINING ingredients that keep the soil wet for longer periods of time. Ponytails are semi-succulents that are native to arid regions. Soil that stays damp for extended periods is NOT what they want. If possible, I would avoid it altogether. If you have no other option, then do mix it with a sandy cactus mix, about 50-50. It is hard to be too specific because every commercial brand is different.

Now for my unsolicited advice.

Ponytail Palms do not like to have their roots disturbed. They much prefer to be kept potbound so the soil dries out more frequently. That is why they are best kept in pots that are just slightly wider than the base bulb and also very shallow.

My concern is that you are about to disturb the roots of a plant that is large and difficult to manage and that you are putting it into a beautiful pot that is substantially larger and will require the addition of more soil and has no drain holes. All of this could be avoided if you were to place the existing pot and plant into the new pot and filling in the space between and over the top with Spanish moss to disguise the double-potting

If you decide to go with your intended plan, then be mindful that you have to be very careful to disturb the roots as little as possible by keeping the rootball intact. In addition, there is  substantially increased risk of root rot, so add as little porous soil as possible and adjust your watering accordingly. Finally, do NOT add any soil to the top of the existing rootball in order to top it off. That extra soil serves no useful purpose and it will prevent needed oxygen from penetrating into the root zone.