How do I prevent root rotting?

[PashkaTLT]

Hello guys,

As some of you may know from my other post my Pindo palm has rotted and died, the bottom half of the roots has rotted and the rot went up to the central spear. I could not save the Pindo palm, but upon closer inspection I found out my 2 Pygmy Date Palm started rotting too. Fortunately, they should be fine, I cut the rotted roots and repotted them.

I know the main causes of root rotting are: 

- overwatering

- lack of oxygen

- fungi

I don't think lack of oxygen was the problem in my case, because I buy soil (I usually mix half of special palm soil and half of general purpose indoor plants soil, because palm soil is pretty expensive) and I add about 20 - 25% of perlite to the mix.

On my Pindo palm, I noted white dots on the rotted places, so I assume fungi may be the cause in the Pindo's case, or perhaps both, fungi + overwatering.

I did not think I overwater my palms, though, because I use one of those soil moisture meters which I poke deep into the soil and water only when the meter shows the soil is in the red, dry zone. I'm not sure that I can trust that meter, though, because when I pulled my palms out of the pots, the bottom halves were pretty moist. Maybe I should water not just when the meter shows the dry zone (levels 1-3 out of 10), but when it goes to the lowest possible level (0 or 1). Or maybe I should even wait a little after the meter shows it's dry? 

So, any advice, guys?

Kind regards,

Pavel

[JLM]

I would try placing the palms in those trays when watering, and once the water has drained, remove the tray and dump the excess water out, and then put back under if you want. I would try to avoid allowing water to stay in those trays and see if that will help your situation. Continue watering based on your moisture meter, but just don’t let water sit in those trays.
 

Also, im sorry to hear about your pindo. Glad you caught the others when you did before it got out of control.

[PashkaTLT]

Thank you, @JLM

I think I've never watered to have more than 1/2" of water in the trays. Do you think it could still be a problem?

[JLM]

1 hour ago, PashkaTLT said:

Thank you, @JLM

I think I've never watered to have more than 1/2" of water in the trays. Do you think it could still be a problem?

If the half inch is enough to keep the soil in the bottom portion of the pot wet, then yes. Need to make sure the bottom half of the pot also has a chance to dry out a little between waterings so those bottom roots aren’t constantly waterlogged. Would just allow it to dry to a point where the soil at the bottom of the pot is moist, not wet, before watering again.

[Leelanau Palms]

I would also correlate with the weight of the pot, the time of the year, and the growth of the palm. Observe the weight of the pot when you are confident that it is dry all the way to the bottom. Then compare that to the weight just after watering. I lift small and medium pots, and tip larger ones to check the weight, if I am unsure about the need for water. Less water is needed in the winter, so err on the drier side in the winter. Less water is needed when there is not active growth, so run them drier when they not growing steadily. My actively growing palms pull water and dry out faster in the same conditions. Other tips: use a lighter soil mix (lots of thread here about that) and consider avoiding a large pot for the size of the palm.

I induced root rot on a potted needle palm last fall by: using too heavy a potting soil, watering too much for the time of year, and assuming that all the soil was as dry as the top 1/3 in the pot. It rotted despite the palm being in bright light and not being in too large a pot. It's leaves started spotting and turning brown. I backed way off on watering. This spring, when I repotted it, I found rotted roots, but also new roots. I repotted it in much lighter soil and am trying to nurse it back to health. It lost ~ 1/2 of its canopy so far. 

[Harry’s Palms]

I don’t know if you already do this , but I usually put a layer of small pebbles or gravel in the bottom of the pot . I also drill extra drain holes if there is only one small hole so that the pot can drain adequately. This can be challenging if the pot is ceramic but a masonary bit and a squirt of water and some patience , you can cut through. If the drain hole is large it won’t need it but I find that some of the large decorative pots don’t have good drainage , nursery pots are usually fine . It’s all about drainage. Harry

[PashkaTLT]

@Leelanau Palms thank you, and good luck with reviving your Needle palm!

@Harry’s Palms thank you. I do put pebbles on the bottom too, and make a lot of large holes. I guess that can still be not enough...

So, basically, guys, my plan is

- wait until the soil is completely dry and not on the border of dry & moist

- perhaps add more perlite to the mix. I add 20 - 25%, but I've watched videos of some people suggesting 40% to prevent root rotting.

- use smaller pots

- water slowly and stop right after I see water start coming on the tray to avoid having a significant water layer on the tray.

[SeanK]

I water potted palms and citrus about once every two weeks in the winter. Mine stay in an unheated room that gets down to about 30°F.

[PashkaTLT]

Hi @SeanK A sun room or a garage I assume?

[SeanK]

A sun room. Enclosed with Windows 

[SubTropicRay]

Somewhat frequent repotting so the lower mix does not become stale helps.  This is probably not the answer anyone wants to hear but it does help.

[PashkaTLT]

@SeanK Nice! I so wish I had a sun room!

@SubTropicRay thanks!

[RFun]

My guess is the soil is logging too much water in that spot.  Also, the palms may have been planted too deeply.  Moisture meters can give false readings as well.  Best to give a decent watering once a week or so.

[Adam_NY]

Use a primarily inorganic mix. I use 2/5 turface, 2/5 pine bark mulch and 1/5 leca pellets.