Rice husk ASH as a palm substrate

[Nigel]

Here in brasil it is very difficult to procure good substrate. All the nurseries here use rice husk ash which I believe is commonly used in substrate in rice growing areas of the world.

I am told it is an inert substance, yet it seems to me that when it is used either in rerooting process after field growing or as part of the substrate in potting mix, the result is a yellow sick palm especially in case of Trachcyarpus fortunei.

I am told here this is impossible it is a very good substrate and this ash is not the problem.

Does anybody have experience with this substrate , I would be very grateful if any of you nursery growers can give your opinions, also Alberto, Gileno , Merrill ... what do you all think about this ???

Thank you.

[cfkingfish]

Nigel-

Interesting topic. I discussed the use of rice hulls in potting mixes with a company here in the USA that started to use them. They said rice hulls were substituted for perlite in mixes for people looking to use a quick mix to sell a plant. The ash of rice should have Sodium, Potassium, and Calcium. I could imagine that without being leached out, the Sodium would caused yellowing, especially in a non-salt tolerant species such as Trachycarpus (an assumption).

[edbrown_III]

Nigel and Ck

Timely topic for me especially---- I just started my initial plamting of philippines property--- I planted red palms and coconuts --- I got all these from a nursery near by --- everything grown in rice hulls the field in from of mine is riverine flood plain and nothering but rice hulls as substrate. Theres a lot of lajar ( volcanic tuft) that might well be a decent substrate for plants

Best regards

Ed

[Alberto]

Here in brasil it is very difficult to procure good substrate. All the nurseries here use rice husk ash which

Nigel,it is not exactly ash, but charcoal or coal (carvão).

I used it for my potted parajubaeas,mixed with soil and sand .It is very well draining material.

[Nigel]

Here in brasil it is very difficult to procure good substrate. All the nurseries here use rice husk ash which

Nigel,it is not exactly ash, but charcoal or coal (carvão).

I used it for my potted parajubaeas,mixed with soil and sand .It is very well draining material.

Thats exactly right alberto, but why is everything yellow, burning in the sun and suffering fungus, identical plants in sawdust 100 yards away are still perfect ????

[edbrown_III]

Here in brasil it is very difficult to procure good substrate. All the nurseries here use rice husk ash which

Nigel,it is not exactly ash, but charcoal or coal (carvão).

I used it for my potted parajubaeas,mixed with soil and sand .It is very well draining material.

Thats exactly right alberto, but why is everything yellow, burning in the sun and suffering fungus, identical plants in sawdust 100 yards away are still perfect ????

The saw dust doesnt steal the Nitrogen (through decomposition?)

Best regards

Ed

[Nigel]

Here in brasil it is very difficult to procure good substrate. All the nurseries here use rice husk ash which

Nigel,it is not exactly ash, but charcoal or coal (carvão).

I used it for my potted parajubaeas,mixed with soil and sand .It is very well draining material.

Thats exactly right alberto, but why is everything yellow, burning in the sun and suffering fungus, identical plants in sawdust 100 yards away are still perfect ????

Ed, I dont understand why this is happening, maybe christian is right about salt tolerance, but rice husk ash is suupposed to be inert, and it drains perfectly so in theory it should be perfect for usage.

The saw dust doesnt steal the Nitrogen (through decomposition?)

Best regards

Ed

[PalmGuyWC]

Nigel,

For some reason rick husk is no longer available in my area, but when I first moved to Walnut Creek, I used it a lot, but only to break up the soil with a rototiller. I have adobe clay and it tends to break up in large clods and stick together. I found out by spreading about 6 inches over the area to be rototilled the clods would be coated with the rice hulls, and then as the clods got smaller and smaller they would be coated and not stick together. I would finally end up with a finely tilled soil that would run through my fingers.

I would dig out the finely tilled soil from the hole, then add more rice hulls, and dig deeper. I could actually dig out a hole deep enough to plant a palm and use the finely tilled soil to fill in around the palm roots. This was the lazy man's way of digging a hole. I doubt if there was any nutritional value in the rice hulls, but it allowed enough air space and oxygen in the soil for the roots to flourish, and it drained well.

I've seen some potting soils from nurserys with rice hulls, but for my taste, it drys out to fast.

Dick

[kahili]

Just read about this product-RHA. What a funky ingredient to grow in. Apparently the # 1 use of it seems to be in making cement-when mixed with lime, it turns into a form of cement. RHA is also banned from several European countries (and more will be added to the list) because of health concerns.

But if others there in Brazil are growing in it without problems, then I wonder if there is something that you are doing, or not doing that they are?

Are you using it as a amendment to other ingredients in your mix? If so, could it be the percentage that you are using?

Are you adding lime to your mix? (lol, I don't see how this could be used in any horticultural application if adding lime to it makes cement?? )

Whats the drainage like in your mixes with it? Are you using liquid fert (foliar fert) and if so, could it be leaching out due to excessive watering if the drainage is too good?

Whats in your mix besides the RHA?

What percentage of your crops are turning yellow and getting fungus that have this RHA in it?

How fast does the plant turn yellow after being transplanted into this mix?

Have you done a PH test of this mix? (that is the first thing that I would do, and then a test to measure the amt of fert in the mix)

What do the roots look like of the sickly plants?

What kind of fungus is it getting?

Alot of questions, I know, but its a puzzle and the answers are all clues to the problem.

[Alberto]

Nigel,something I also see in my potted plants,that to porose well draining soil mixes,sometimes easily forms ´´cochonilhas´´(don´t remember the English word now )on the roots (ants can easily acces the roots and ´´cultivate´´them there IN the pot).

´´Casca de arroz queimado´´that is charcoal of rice husks. If you burn the charcoal to much,then it transforms in ASH (like you said) and ash is very alkaline..........

[Nigel]

Alberto, the cochinilla is a much bigger problem in the sawdust, it doesnt seem to like the rice ash.

Kahili, the Trachycarpus roots very quickly into rice ash.

The PH is around 5,5 when tested because this is the PH of the groundwater and soil here.

I believe that it is somehow locking up the nutrients,especially potassium. However, without some proof or solid arguments I have a big problem to persuade the locals to stop using it.

It is a waste product here, very cheap , very popular and seems to work well with most plants.... but Trachycarpus in my opinion hates it and I need to find out why.

[tropicbreeze]

You'll find it's the charcoal in the rice ash which is the problem. Fresh charcoal absorbs nitrogen and will initially rob the soil. People who use charcoal often soak it for a few hours in a nitrogen rich fertiliser. Once a balance is reached it helps increase the CEC.

[kahili]

Nigel,it makes sense that its a nutrient/PH problem, but why just the trachys. If its that severe a problem with them, then it seems that it would be a problem with at least some other plants or palms as well-not just the Trachies. Also-I don't think that 5.5 is low enough to start blocking nutrients with Trachies. I would still run a PH test on the mix that the Trachys are in. My guess is that the PH is off a lot more than that or its something else. What is the range of PH that Trachies can grow in without problems? Thats why I asked what was in your mix besides the RHA. What other amendments are you adding to the mix? Are you using slow release or foliar fert?

[kahili]

So if its true that charcoal will use the nitrogen when breaking down, then I would start hitting the trachys with a soluble fert with high nitrogen (like a 20-10-20) every week at about 300-400 ppm (depending on the root size of the palms) and see what happens after a few wks. Making sure that the palms had at least one good watering before fertilizing that wk to leach out some of the salts.

[Tyrone]

Nigel, just to get it clear, you did test the pH of the final mix didn't you? Pure ash has a pH of about 10. As others have said you must leach it too. Turning an organic substance into ash reduces the carbon content of the substance but leaves all the trace elements behind, however the resultant substance is very high in pH. If I've put ash into a mix, I'd never put lime as well. Lime is put in to buffer the effect of sawdust decomposing over time and dropping the pH.

Nigel, do your Trachies go yellow first in the new growth, is it a fast transformation or is it gradual? The leaves that yellow, do they have green veins still. Is there distorted or small new growth. Are there blotchy patterns of green to yellow?

Best regards

Tyrone

[tropicbreeze]

Charcoal is relatively inert, it's the molecular structure from its formation that helps it absorb cations/anions, as do clay particles. Activated charcoal is even better than ordinary charcoal. In the burning process the sulphur and nitrogen are lost, most of the cations remain so that pH goes sky high. The charcoal needs to get a balance back, plants in it at that time are the losers. That's why fresh charcoal can have such a devastating effect. I've done it with bananas, which are gross feeders. With ash that had been laying around in the weather up to a year they still suffered badly. With the charcoal soaked at least a few hours, although the longer the better, the bananas rocketed off. I'm confident enough now to be doing it on a larger scale in garden beds. But I add urea to help the process and earthworms are great assistants.

[kahili]

I have a hard time believing that the Trachys would be the only plants freaking out with a PH of 10. there would have to be other plants suffering in obvious ways. However, if the PH were to be 10, the quickest way to get the PH down would be to use sulfuric acid every time that you watered, and to use enough of it with the water or fert solution that the PH of the solution/water would be down around 3.5.(its only about a few drops per gallon-not positive about that, I run it through an injector at a rate of 1:200, so I use alot at a time) You should see results in maybe a month, I think it would take that long just to get it down a few pts, and then have the nutrients be unblocked.

You can use battery acid ( I would think its the same everywhere-35% sulfuric acid).

In fact if you can't do an accurate PH or EC test, I would take a few of the trachys and put them on a 300-400 ppm foliar fert (assuming that you don't have a slow release fert in the mix), another few I would do the watering with the sulfuric acid, and another few I would do the foliar fert with the sulfuric acid in the solution and see what the results are.

[Nigel]

This is a very interesting discussion guys. Rice husk ash is not the same as other ash, and the soil when tested always was a ph of 5,5.

The substrate is brought in ready mixed equal parts of pine bark chips, local peat and rice hush ash.

We have tried all sorts of fertilisation. We exported plants in the past and they have burned in the container but we dont know why.

I suspect the ph remains low because the water from the tap here has a ph of 5,5.

Edited June 4, 2010 by Nigel

[Tyrone]

Nigel, if it's all premixed when you get it and you say it has a pH of 5.5, they've either added something to drop the pH, or the peat has done it. Proper peat has a pH of 4.5 roughly.

What exact symptoms are your plants showing?

I tried using blue metal dust once in my mixes and some of them I used too much. Blue metal dust I found out later has a high pH. Anyway most things were fine with it, but Beccariophoenix developed iron deficiencies with it. Also it may have had too much aluminium in it, which blocks iron uptake. If we can narrow down what deficiency symptoms your Trachies are showing we should be able to figure out what is lacking and maybe why.

Best regards

Tyrone