My soil components AFP/WHC

Scrixx

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Hello all, it's been about 9 months since I've made a post.

This is continuing my post from before. I ended up doing an experiment to get the values. I have since gotten more soil components and will be repotting my plants this spring. I let them grow out last year when I got them. Expect more posts from me with my trees!

Particle size are 1/8"-3/16"
Terms:
AFP - air filled porosity - percentage of the soil that's air
WHC - water holding capacity - percentage of the soil that's water

My thoughts on this:
My initial soil mix was 3 pumice:3 lava rock:1 Diatomaceous earth(DE) :1 forest products(FP). It gave 24% AFP and 32% WHC. Total porosity was 56%, AFP was beautiful but the WHC was too low. I added another portion of DE and FP. Making the mix 3:3:2:2, but that shot the porosity down to 11% which is not good at all but increased WHC to 43%.

I believe the problem is that my DE is smaller than the rest of the components despite being sifted to 1/8"-3/16". It filled the spaces between the other components and ruined the porosity in exchange for 43% WHC. If I were able to get larger DE I think it would keep the porosity higher and increase WHC. Since I don't have that, I'll be sticking to my initial mix of 3:3:1:1. I considered adding more forest products but I did not want very much organics in my mix and I don't even know what it is. Just that it looks to be about 70% bark. So I erred on the side of caution. I used it to up the WHC a bit.

Thoughts? I'd like to up the WHC more but adding DE will ruin my porosity. What can be done to increase WHC?

Another interesting thing is the DE. It's Napa #8822. The AFP is 16% and the WHC is 43%. 16% AFP is a little low but the WHC is actually good. Maybe this is why some people have success in 100% DE? It's not perfect but it provides quite an acceptable AFP/WHC.

The pumice and lava rock are actually very similar. I heard lava rock is suppose to retain more water than pumice. Though maybe my pumice is weird or not really pumice? I heard pumice is suppose to float but mine do not. Not sure but what I get from this is that they're pretty interchangeable.

Special disclaimers:
I'm just a guy and this was a backyard/garage experiment.
Don't expect perfect results but they're good enough as rough guidelines.

Old topic:
https://www.bonsainut.com/threads/diatomaceous-earth-c-e-c-and-whc.27494/#post-451971
 

Vance Wood

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Hello all, it's been about 9 months since I've made a post.

This is continuing my post from before. I ended up doing an experiment to get the values. I have since gotten more soil components and will be repotting my plants this spring. I let them grow out last year when I got them. Expect more posts from me with my trees!

Particle size are 1/8"-3/16"
Terms:
AFP - air filled porosity - percentage of the soil that's air
WHC - water holding capacity - percentage of the soil that's water

My thoughts on this:
My initial soil mix was 3 pumice:3 lava rock:1 Diatomaceous earth(DE) :1 forest products(FP). It gave 24% AFP and 32% WHC. Total porosity was 56%, AFP was beautiful but the WHC was too low. I added another portion of DE and FP. Making the mix 3:3:2:2, but that shot the porosity down to 11% which is not good at all but increased WHC to 43%.

I believe the problem is that my DE is smaller than the rest of the components despite being sifted to 1/8"-3/16". It filled the spaces between the other components and ruined the porosity in exchange for 43% WHC. If I were able to get larger DE I think it would keep the porosity higher and increase WHC. Since I don't have that, I'll be sticking to my initial mix of 3:3:1:1. I considered adding more forest products but I did not want very much organics in my mix and I don't even know what it is. Just that it looks to be about 70% bark. So I erred on the side of caution. I used it to up the WHC a bit.

Thoughts? I'd like to up the WHC more but adding DE will ruin my porosity. What can be done to increase WHC?

Another interesting thing is the DE. It's Napa #8822. The AFP is 16% and the WHC is 43%. 16% AFP is a little low but the WHC is actually good. Maybe this is why some people have success in 100% DE? It's not perfect but it provides quite an acceptable AFP/WHC.

The pumice and lava rock are actually very similar. I heard lava rock is suppose to retain more water than pumice. Though maybe my pumice is weird or not really pumice? I heard pumice is suppose to float but mine do not. Not sure but what I get from this is that they're pretty interchangeable.

Special disclaimers:
I'm just a guy and this was a backyard/garage experiment.
Don't expect perfect results but they're good enough as rough guidelines.

Old topic:
https://www.bonsainut.com/threads/diatomaceous-earth-c-e-c-and-whc.27494/#post-451971
You question: Thoughts? I'd like to up the WHC more but adding DE will ruin my porosity. What can be done to increase WHC? Water more often. It is far better to have a soil that has a low field capacity, what you call WHC (Water holding capacity) and have a great porocity than have a soil that stays wet and is a threat to becoming sour. The soil that does not hold a lot of water will breath, a soil that does not drain well will suffocate.
 

River's Edge

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Hello all, it's been about 9 months since I've made a post.

This is continuing my post from before. I ended up doing an experiment to get the values. I have since gotten more soil components and will be repotting my plants this spring. I let them grow out last year when I got them. Expect more posts from me with my trees!

Particle size are 1/8"-3/16"
Terms:
AFP - air filled porosity - percentage of the soil that's air
WHC - water holding capacity - percentage of the soil that's water

My thoughts on this:
My initial soil mix was 3 pumice:3 lava rock:1 Diatomaceous earth(DE) :1 forest products(FP). It gave 24% AFP and 32% WHC. Total porosity was 56%, AFP was beautiful but the WHC was too low. I added another portion of DE and FP. Making the mix 3:3:2:2, but that shot the porosity down to 11% which is not good at all but increased WHC to 43%.

I believe the problem is that my DE is smaller than the rest of the components despite being sifted to 1/8"-3/16". It filled the spaces between the other components and ruined the porosity in exchange for 43% WHC. If I were able to get larger DE I think it would keep the porosity higher and increase WHC. Since I don't have that, I'll be sticking to my initial mix of 3:3:1:1. I considered adding more forest products but I did not want very much organics in my mix and I don't even know what it is. Just that it looks to be about 70% bark. So I erred on the side of caution. I used it to up the WHC a bit.

Thoughts? I'd like to up the WHC more but adding DE will ruin my porosity. What can be done to increase WHC?

Another interesting thing is the DE. It's Napa #8822. The AFP is 16% and the WHC is 43%. 16% AFP is a little low but the WHC is actually good. Maybe this is why some people have success in 100% DE? It's not perfect but it provides quite an acceptable AFP/WHC.

The pumice and lava rock are actually very similar. I heard lava rock is suppose to retain more water than pumice. Though maybe my pumice is weird or not really pumice? I heard pumice is suppose to float but mine do not. Not sure but what I get from this is that they're pretty interchangeable.

Special disclaimers:
I'm just a guy and this was a backyard/garage experiment.
Don't expect perfect results but they're good enough as rough guidelines.

Old topic:
https://www.bonsainut.com/threads/diatomaceous-earth-c-e-c-and-whc.27494/#post-451971
Pumice holds and makes the water available better than lava. The explanation is connected with the size and shape of the pores. So they are not really considered interchangeable. The pumice releases the water for plant use more easily. Lava can not be expected to produce the same results as pumice. You are correct in being concerned about particle size and interfering with porosity.
 

Scrixx

Seedling
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You question: Thoughts? I'd like to up the WHC more but adding DE will ruin my porosity. What can be done to increase WHC? Water more often. It is far better to have a soil that has a low field capacity, what you call WHC (Water holding capacity) and have a great porocity than have a soil that stays wet and is a threat to becoming sour. The soil that does not hold a lot of water will breath, a soil that does not drain well will suffocate.

Yeah but I'm trying to increase the WHC. Just watering more is dodging the problem and question. I understand that higher AFP is better than low and sacrificing some WHC is a good idea but at the same time I live in Southern California and I'm worried the trees may not last a whole day in between watering.
 

Scrixx

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Pumice holds and makes the water available better than lava. The explanation is connected with the size and shape of the pores. So they are not really considered interchangeable. The pumice releases the water for plant use more easily. Lava can not be expected to produce the same results as pumice. You are correct in being concerned about particle size and interfering with porosity.

Interesting, that kind of makes sense. Do you know if there's any posts I can read on about that?
 

River's Edge

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Interesting, that kind of makes sense. Do you know if there's any posts I can read on about that?
Lots of comments on B Nut, type in (pumice and lava comparison ) . I researched the specifications supplied by the sources i use for black lava and pumice. The black lava i prefer is from CANLAVA sold as Tephragro. their website has all the scientific data. Including density and vesicle size. The devil is in the details.
 
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