Question
About five months ago I acquired a small ponytail palm, which until recently was doing well located directly in front of a west-facing double patio door, approximately one foot from the glass, where it receives maximum light I can provide. However, a couple weeks ago, the leaves began tipping and I need your help to narrow the cause.

The plant remains in its original 6" plastic grow pot, double potted in an unglazed ceramic container which has a single, large drainage hole. Yes, once or twice, maybe thrice, I've read your admonitions not to repot but, oh, the temptation! Maybe repainting the clay pot will suffice as a substitute fix - hmmm which color best expresses a ponytail's inner nature?... But I digress. (And yes, wonder no more, I live on the west coast.)  

This being my first ponytail, I don't yet have an intimate knowledge of the plant and, thus, am somewhat uncertain how to properly water it, mostly because the potting medium is a bit coarse and with not much humus, not as coarse as orchid mix but enough so that it is difficult to accurately discern moisture levels. I know that ponytails thrive in drier conditions but wonder if underwatering is insidiously causing the tipping. Or could the tipping be caused by a recent watering lapse? Or could it be something else? Although I've not had the municipal water tested, my other plants do not show symptoms of hard water.

Perhaps my concern is premature - tipping so far is minimal and the plant still looks terrific, lush and full (except for a few cat-mutilated lower leaves), and regularly produces healthy new growth, however, I want to  narrow the cause of the tipping BEFORE it becomes a major problem and to learn how to appropriately water the plant. I don't know if this tidbit of information is helpful but I use a Soil Sleuth probe as a watering aid.

Please let me know if I've left out any relevant information. Photos are readily available if you think them helpful.

Thank you, Will for your help!

Regards,

Answer
Hi West Coast Maggie,

Thank you for providing such detailed information about your ponytail palm and also for contacting me BEFORE your plant was in serious trouble.

The dry brown tips on older ponytail palm leaves is almost unavoidable, not unlike the tipping that occurs on spider plants. (BTW, both spider plants and ponytails are in the Lily family!) If anything at all is wrong in a ponytail's environment, it will show up first as brown tips.

The light that your described is fine for a ponytail as along as the patio door window is uncovered and unobstructed.

It is also good that you resisted the impulse to repot. Ponytails do need to be in small pots that dry out fairly quickly after a good soaking. That is why they need to be in small pots not much bigger than their base bulbs and also why they need to be potted in a very porous soil that has added perlite or other granular material.

Watering too frequently will cause the roots to rot and the plant to die. Underwatering will cause lower leaves to dry up and drop off, but will not cause the plant to die except in extreme drought. So it is always best to err on the side of watering less frequently.

Your Soil Sleuth (www.soilsleuth.com) is a good tool to determine how moist the soil is. In general, the soil should dry out about halfway down into the pot. However, in good light and a small pot it may be best to let only the top quarter of the soil dry out.

Ponytails are sensitive to an excess of minerals in the soil. So both hard water and excess fertilizing can also cause leaf tipping.

Finally, I will note that it is quite normal and inevitable for older leaves of a ponytail to gradually turn brown and die as new growth is added on top. As long as you are periodically seeing lots of healthy new growth, then your plant is doing fine and there is no reason to change anything.

Please let me know if any of this is unclear or if you have any additional questions.

Visit my website at  www.HorticulturalHelp.com

If you would like to e-mail me some photos, I may be able to provide some additional insights.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

You can E-mail me directly at: [email protected]