Dealing with high pH soils

[Tyrone]

Lately I've been dealing with high pH sandy soils, trying to help different people get their gardens performing on limestone. These are common along the western coastline of Australia right up into the tropics, and I know certain parts of Florida and the Keys have the same issues. These soils are basically marine derived and have large amounts of Calcium carbonate often in percentages in the soil. Dropping the pH even a couple of points can be extremely difficult due to the actual presence of pure Calcium carbonate rocks in the soil. Typically these soils are in excess of a pH of 8 and can go right up into the 9's. The theory is, if your raw soil has a pH of 8.4 or above you are basically fighting a losing battle as you may have up to 5% pure limestone in the mix. This is because what ever acidifying agent you put into the soil must react with all the available calcium carbonate before the pH will start to go down at all. This can require enormous amounts of sulfur, iron sulfate or ammonium sulfate, and in most cases this is totally impractical.

The biggest problem with high pH is that it locks up iron first rather tightly. So iron is the first deficiency you'll see, that is yellowing new growth, that may eventually yellow out the leaf veins and in extreme cases cause a serious whitening and then sunburn of the leaf. Usually these extremely deficient leaves can not be brought back. High pH can also lock other trace elements like Manganese, Zinc, etc.

I came across this interesting way of getting iron deficient plants growing on limestone soils healthy again, and to me it makes sense. It should be applied with some sort of acidifying action to the surrounding soil, but this technique should give trace element deficient plants a shot in the arm while the rest of the soil takes it's time to react with other treatments.

Basically you get one cup (approx 230g) of iron sulfate, and mix it with 10l (a bucket) of compost, well rotted manure (NOT CHICKEN MANURE), or peat. You then dig a series of holes about 1ft deep or more around your deficient palms and plants, and stuff it full of the iron rich compost mix. You then water it in heavily. Eventually the roots will in theory make their way into these pockets of rich nutrients and because they are quite strong, the surrounding limestone can't lock up the nutrients quickly. This treatment is meant to last a few years, although it would depend on the pH of the soil and nutrient demands of the plant. Also you could probably add other trace elements this way, but of course not going over the 230g/ 10L bucket ratio.

I thought this may be of some use to those on Palmtalk in similar situations. I know that Wodyetia's can seriously set back when the pH is high. They can get all sorts of nutrient and growth issues then fungi come along and finish them off. I hope this can be of some use to others, and it would be interesting to hear what others think of this treatment.

Best regards

Tyrone

[Manolitus]

Lately I've been dealing with high pH sandy soils, trying to help different people get their gardens performing on limestone. These are common along the western coastline of Australia right up into the tropics, and I know certain parts of Florida and the Keys have the same issues. These soils are basically marine derived and have large amounts of Calcium carbonate often in percentages in the soil. Dropping the pH even a couple of points can be extremely difficult due to the actual presence of pure Calcium carbonate rocks in the soil. Typically these soils are in excess of a pH of 8 and can go right up into the 9's. The theory is, if your raw soil has a pH of 8.4 or above you are basically fighting a losing battle as you may have up to 5% pure limestone in the mix. This is because what ever acidifying agent you put into the soil must react with all the available calcium carbonate before the pH will start to go down at all. This can require enormous amounts of sulfur, iron sulfate or ammonium sulfate, and in most cases this is totally impractical.

The biggest problem with high pH is that it locks up iron first rather tightly. So iron is the first deficiency you'll see, that is yellowing new growth, that may eventually yellow out the leaf veins and in extreme cases cause a serious whitening and then sunburn of the leaf. Usually these extremely deficient leaves can not be brought back. High pH can also lock other trace elements like Manganese, Zinc, etc.

I came across this interesting way of getting iron deficient plants growing on limestone soils healthy again, and to me it makes sense. It should be applied with some sort of acidifying action to the surrounding soil, but this technique should give trace element deficient plants a shot in the arm while the rest of the soil takes it's time to react with other treatments.

Basically you get one cup (approx 230g) of iron sulfate, and mix it with 10l (a bucket) of compost, well rotted manure (NOT CHICKEN MANURE), or peat. You then dig a series of holes about 1ft deep or more around your deficient palms and plants, and stuff it full of the iron rich compost mix. You then water it in heavily. Eventually the roots will in theory make their way into these pockets of rich nutrients and because they are quite strong, the surrounding limestone can't lock up the nutrients quickly. This treatment is meant to last a few years, although it would depend on the pH of the soil and nutrient demands of the plant. Also you could probably add other trace elements this way, but of course not going over the 230g/ 10L bucket ratio.

I thought this may be of some use to those on Palmtalk in similar situations. I know that Wodyetia's can seriously set back when the pH is high. They can get all sorts of nutrient and growth issues then fungi come along and finish them off. I hope this can be of some use to others, and it would be interesting to hear what others think of this treatment.

Best regards

Tyrone

Tyrone,

Thanks so much for the advise; I will try it. Here in Miami, this is certainly our achilles heal for many many palms. Its a very tough battle. Even when very large holes are dug ( through solid rock, mind you ) the ph has a way of creeping up because so many people irrigate from well water, which of course comes from the ground !!! City water does not make it any better because its treated with a bunch of stuff.

A couple of years ago, I dug a huge hole and put in some great soil, so that I could try to plant some truly exotic stuff. Well, the Marojejya I planted is now exhibiting much of the same ailments which you have described in your post.

Either way, I will give your experiment a shot. Got nothing to lose !!!

Manny

[BS Man about Palms]

Tyrone, I like reading your well worded and researched soil tirades/infomercials!

[Tyrone]

Tyrone, I like reading your well worded and researched soil tirades/infomercials!

Bill, I'm glad you liked it.

I thought it would be of some use to those who are stuck in this sort of predicament and lost as to what to do. Just this week I had a guy from Exmouth up in the tropics of West Oz contact me and tell me what was happening to his palm garden. He wanted some bottle spindle crosses and we had a chat about his garden. His foxtails are seriously in trouble and his property is on limestone cap rock. When he digs a hole he needs to smash areas out. To make matters worse he lives in a remote country town which does not have access to bulk amounts of manures and composts without a huge expense. He does have access to large amounts of seaweed though.

Hopefully this bit of info could help those with these sort of issues even a little bit.

Best regards

Tyrone

[tropicbreeze]

This is the method I know as a cheap alternative to buying chelated iron and other chelated elements. Iron sulphate is much cheaper to buy than chelated iron.

[rozpalm]

Wow, what a great idea! Thanks for sharing that Tyrone.

[BS Man about Palms]

Tyrone, I like reading your well worded and researched soil tirades/infomercials!

Bill, I'm glad you liked it.

I thought it would be of some use to those who are stuck in this sort of predicament and lost as to what to do. Just this week I had a guy from Exmouth up in the tropics of West Oz contact me and tell me what was happening to his palm garden. He wanted some bottle spindle crosses and we had a chat about his garden. His foxtails are seriously in trouble and his property is on limestone cap rock. When he digs a hole he needs to smash areas out. To make matters worse he lives in a remote country town which does not have access to bulk amounts of manures and composts without a huge expense. He does have access to large amounts of seaweed though.

Hopefully this bit of info could help those with these sort of issues even a little bit.

Best regards

Tyrone

It's kinda all Greek to me, but I can and do take something away from it...