I know a few of us have been experimenting with acidifying the water used on our cactus. I've been doing it on an off for a couple of years.
I recently started using citric acid to acidify the water. Most people start out with white vinegar because they usually have it around the house. I've found the citric acid to be much easier to deal with. I would use about 1 OZ. of vinegar per gallon of water. When you make a 30 gallon batch that starts to become a LOT of vinegar. I can acidify the same 30 gallons with 2 teaspoons of citric acid.
I got the citric acid on ebay for cheap.
A lot of the information that I've been using to guide me has been from the articles by Malcolm Burleigh and Elton Roberts in the CSSA Journal. Their recent article in the July/August edition talks about an interesting concept in fertilizing that should be beneficial to your plants. This is in addition to acidulating the water.
The article recommends using potassium sulfate, ammonium sulfate and a high phosphorus flowering fertilizer with every watering during the growing season. It took me a little while but I've got all the stuff I need to try this out in the spring.
Did anyone else read this article or are going to try the method outlined?
Acidifying water...
Acidifying water...
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.
Tim
Tim
It's been a while since I've played with nuits. So 12-12-14. 14 would be my phospherous right? They're outlawing phospherous in NY (if it is the third number) I always mix up the P's! It's bad for the enviroment or something...? Oops I guess I'm a little off topic.
Thirsty for knowledge. Please water me more than your cactus!
Phosphorus is the middle number.
As they always say, if you outlaw phosphorus, only outlaws will have phosphorus!
The K is for potassium!
The gist of the article is that plants actually take up ammonium and most plants get an assist from soil bacteria to convert nitrogen to ammonium. Cacti soil generally doesn't support a bacteria very well.
As they always say, if you outlaw phosphorus, only outlaws will have phosphorus!
The K is for potassium!
The gist of the article is that plants actually take up ammonium and most plants get an assist from soil bacteria to convert nitrogen to ammonium. Cacti soil generally doesn't support a bacteria very well.
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.
Tim
Tim
Cacti still need bacteria to convert their nitrogen. Desert soils contain relatively little of anything with nitrogen in it, relatively little bacteria, and relatively little water which is also needed for the process. Therefore not a lot of nitrogen for the cacti, but then most of them are unable to use a lot of nitrogen anyway. There are some sources of nitrates directly without bacterial intervention, principally rainwater "enriched" by lightning or pollution.
I haven't read the article yet but if it claims that plants only take up nitrogen in ammonium form then it is wrong. Nitrate is usually considered the primary ion form for plants to take up nitrogen, although they do also take up ammonium ions directly and the balance between the two produces some interesting effects. Many sulphate and nitrogen fertiliser chemicals have an acidifying effect in soil without actually being acids themselves, one reason that lawn growers and farmers often have to regularly lime their crops. Using a siotable fertiliser compound, even with the same NPK values, can help you to control soil acidity to your benefit, but high use of sulphate chemicals (or their high nitrogen equivalents) can equally be harmful when they are not needed. I have tried a number of these "wonder" treatments and found little effect from any of them, presumably because my pots don't suffer from the deficiencies or imbalances that they would correct. In particular, additional of sulphur to pots has produced root loss even on plants that thrive in an ericaceous soil.
The New York phosphorus ban should only affect lawn fertilisers (and some cleaning products) but I have no idea quite how it will affect the availability in pot plant fertilisers.
Comparing the addition of 5% acetic acid (household vinegar) with 100% citric acid (do you use powder?) doesn't really tell the whole story. The two acids are very similar in their ability to neutralise alkalis, although highly concentrated acetic acid is quite a nasty substance and you wouldn't want to play around with it. Sulphuric acid is also quite nasty in concentrated form, but more effective at neutralising alkalis and with the benefit of leaving sulphates in the water, so it is a favourite of professional growers. Phosphoric acid is also effective and leaves behind even more useful phosphates but you then have to make sure you don't over-fertilise with phosphorus.
I haven't read the article yet but if it claims that plants only take up nitrogen in ammonium form then it is wrong. Nitrate is usually considered the primary ion form for plants to take up nitrogen, although they do also take up ammonium ions directly and the balance between the two produces some interesting effects. Many sulphate and nitrogen fertiliser chemicals have an acidifying effect in soil without actually being acids themselves, one reason that lawn growers and farmers often have to regularly lime their crops. Using a siotable fertiliser compound, even with the same NPK values, can help you to control soil acidity to your benefit, but high use of sulphate chemicals (or their high nitrogen equivalents) can equally be harmful when they are not needed. I have tried a number of these "wonder" treatments and found little effect from any of them, presumably because my pots don't suffer from the deficiencies or imbalances that they would correct. In particular, additional of sulphur to pots has produced root loss even on plants that thrive in an ericaceous soil.
The New York phosphorus ban should only affect lawn fertilisers (and some cleaning products) but I have no idea quite how it will affect the availability in pot plant fertilisers.
Comparing the addition of 5% acetic acid (household vinegar) with 100% citric acid (do you use powder?) doesn't really tell the whole story. The two acids are very similar in their ability to neutralise alkalis, although highly concentrated acetic acid is quite a nasty substance and you wouldn't want to play around with it. Sulphuric acid is also quite nasty in concentrated form, but more effective at neutralising alkalis and with the benefit of leaving sulphates in the water, so it is a favourite of professional growers. Phosphoric acid is also effective and leaves behind even more useful phosphates but you then have to make sure you don't over-fertilise with phosphorus.
--ian
I love all the threads on soil and water chemistry and plant physiology. I always learn something.
This last growing season, with pretty much every watering, I used Jack's Classic Blossom Booster 10-30-20, a soluble powder. 5% ammoniacal nitrogen and 5% nitrate nitrogen, according to the label. I mixed two tablespoons into a hose end mixer/sprayer and set it for 1 tablespoon of that mixture per gallon of regular Tempe tap water, which is rather hard. The hose end sprayer mixture would easily last for very thorough waterings, probably about 10-12 gallons of water altogether.
Many plants loved this regimen and put on spectacular growth and flowers. One entire group of plants that did not seem to appreciate the fertilizer was Echinocereus. Too much weak new growth, a paler epidermis and no real visible benefit. Some plants showed malformed flowers with stunted petals, also. Other plants continued to grow into what should be the resting season. I think there was nutrient buildup in the plants/soil and they are still metabolizing all that food. For many plants, the challenge was to provide them with enough direct sunlight to maintain strong new growth at their accelerated growth rate, but without frying them. I have always preferred a relatively "hard grown," natural look for cacti and using this rich fertilizer has been a real departure for me.
I would particularly caution growers with much lower light levels than those here in Tempe, Arizona to go easy on fertilizer.
Next year, I will scale down the concentration significantly and reduce the frequency of feedings. I used to use Schultz Cactus Fertilizer 2-7-7 and perhaps I will move back to these lower numbers, as my methods with the higher numbers are so unscientific and loose. If one is just randomly firing a gun, it had better only be a BB gun.
peterb
This last growing season, with pretty much every watering, I used Jack's Classic Blossom Booster 10-30-20, a soluble powder. 5% ammoniacal nitrogen and 5% nitrate nitrogen, according to the label. I mixed two tablespoons into a hose end mixer/sprayer and set it for 1 tablespoon of that mixture per gallon of regular Tempe tap water, which is rather hard. The hose end sprayer mixture would easily last for very thorough waterings, probably about 10-12 gallons of water altogether.
Many plants loved this regimen and put on spectacular growth and flowers. One entire group of plants that did not seem to appreciate the fertilizer was Echinocereus. Too much weak new growth, a paler epidermis and no real visible benefit. Some plants showed malformed flowers with stunted petals, also. Other plants continued to grow into what should be the resting season. I think there was nutrient buildup in the plants/soil and they are still metabolizing all that food. For many plants, the challenge was to provide them with enough direct sunlight to maintain strong new growth at their accelerated growth rate, but without frying them. I have always preferred a relatively "hard grown," natural look for cacti and using this rich fertilizer has been a real departure for me.
I would particularly caution growers with much lower light levels than those here in Tempe, Arizona to go easy on fertilizer.
Next year, I will scale down the concentration significantly and reduce the frequency of feedings. I used to use Schultz Cactus Fertilizer 2-7-7 and perhaps I will move back to these lower numbers, as my methods with the higher numbers are so unscientific and loose. If one is just randomly firing a gun, it had better only be a BB gun.
peterb
Zone 9
According to the article, CAM plants "...the relative rate of ammonium uptake and assimilation is at least ten fold greater than nitrate uptake."
The article recommends to use ammonium with a balanced fertilizer with acidified water.
I guess if I could find powdered acetic acid it would be more equal absolute comparison. I was thinking more along the lines of what's normally available. I haven't looked for powdered acetic acid. As I recall the supposition is that salt deposits left by alkaline hard water acidified with citric acid are more water soluble (easier to rinse/clean off).
Sulphate and nitrogen have acidifiying effects on soil that is moist and supports the bacteria necessary to create the acids. Not necessarily cactus soil.
The article recommends to use ammonium with a balanced fertilizer with acidified water.
I guess if I could find powdered acetic acid it would be more equal absolute comparison. I was thinking more along the lines of what's normally available. I haven't looked for powdered acetic acid. As I recall the supposition is that salt deposits left by alkaline hard water acidified with citric acid are more water soluble (easier to rinse/clean off).
Sulphate and nitrogen have acidifiying effects on soil that is moist and supports the bacteria necessary to create the acids. Not necessarily cactus soil.
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.
Tim
Tim
Did they give a reference to the original source?TimN wrote:According to the article, CAM plants "...the relative rate of ammonium uptake and assimilation is at least ten fold greater than nitrate uptake."
Don't try. Pure acetic acid is a liquid at room temperature. It is nasty to work with, the smell is overwhelming.TimN wrote:I haven't looked for powdered acetic acid.
There's very little difference between the deposits left by acetic acid or citric acid. Calcium acetate is highly soluble and calcium citrate is soluble enough that it shouldn't matter at the concentrations you'll be using. The carbonate byproducts are exactly the same. I'm not sure about the speed of the reactions, but it is likely to depend far more on the pH than on the exact acid being used.
I'd also like to see a source for the claim that CAM plants predominantly take up nitrogen in ammonium form. I searched for any papers that might suggest that and all I could come up with actually showed the opposite with a strong preference for nitrate in one Kalanchoe species, especially in drought conditions. The actual situation probably depends very much on soil conditions and the quantities of fertiliser supplied. Any ammonium not taken up immediately by plants is converted to nitrate fairly quickly by bacteria, and then either taken up by plants or lost from the soil. In the majority of species, nitrate is considered to produce a more rapid response than ammonium, hence the need to never apply too much nitrate at once. Ammonium is more persistant in soil, with most losses being after conversion to nitrate form. These effects will be much less predictable in a pot because the bacterial activity will be unreliable, doubly so in a succulent pot where the water supply is also unreliable. Nitrate is only held in solution, with ammonium ions actually being bound to clay or humus particles.
I'm always wary of "fad diets" ...
I'd also like to see a source for the claim that CAM plants predominantly take up nitrogen in ammonium form. I searched for any papers that might suggest that and all I could come up with actually showed the opposite with a strong preference for nitrate in one Kalanchoe species, especially in drought conditions. The actual situation probably depends very much on soil conditions and the quantities of fertiliser supplied. Any ammonium not taken up immediately by plants is converted to nitrate fairly quickly by bacteria, and then either taken up by plants or lost from the soil. In the majority of species, nitrate is considered to produce a more rapid response than ammonium, hence the need to never apply too much nitrate at once. Ammonium is more persistant in soil, with most losses being after conversion to nitrate form. These effects will be much less predictable in a pot because the bacterial activity will be unreliable, doubly so in a succulent pot where the water supply is also unreliable. Nitrate is only held in solution, with ammonium ions actually being bound to clay or humus particles.
I'm always wary of "fad diets" ...
--ian
When I get home, I'll post the references cited. It was in the CSSA journal from July/August. They listed their references at the back of the article.
I'm in Georgia until tomorrow. Don't have it handy...
I'm in Georgia until tomorrow. Don't have it handy...
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.
Tim
Tim
Here is the references from the end of the article in the CSSA Journal No 4, Jul/Aug 2010.
I can't vouch for the links, I copied them from the journal.
It helps if I include the info...
1. Burleigh M./ Elton Roberts, and D Russell Wagner, Acidic Solutions, adjusting water’s pH improves plant growth, Cactus and Succulent Journal 80, (5) Sept/Oct 2008, pp. 245-250
2. Brown R. Growing Cacti and Succulents for the Beginner – “Are you buying steak or getting hamburger?” Part 8 CSSA Newsletter 68, (2), Mar/Apt (sic) 1996 pp. 25, 28, 29
3. Arndt SK, Wolfgang Wanek and Gunther Hoch, Andreas Richter and Marianne Popp, Flexibility of nitrogen metabolism in the tropical C3-crassulacean acid metabolism tree species Clusia minor http://cat.inist.fr/?aModele=afficheN&cpsidt=13712439
4. Fernandes J, Ricardo M Chaloub and Fernanda Reinert, Influence of nitrogen supply on the photoprotective response of Neoregelia cruenta under high and low light intensity
http://www.publish.csiro.au/paper/PP01209
5. Ruan J, Gerendas J, Hardter R and, Sattelmacher B, Effect of nitrogen form and root-zone pH on growth and nitrogen uptake of tea (Camellia sinensis) plants. Institute for Plant Nutrition and Soil Science, Kiel University, Kiel, D-21098, Germany. jruan@mail.tricaas.com
http://www.ncib.nlm.nih.gov/pubmed/17204540
6. Britto DT, Herbert J Kronzucker NH4+ toxicity in higher plants: a critical review, J. Plant Phiol. 15+.567-584 (2002) Urban & Fischer Verlag
http://www.urbanfischer.de/journals/jpp
7. Buxbaum F, Cactus Culture Based on Biology, pp. 34-44 Blanford Press, London, 1958
8. Brown R, The Cactus Family Timber Press, Portland, Cambridge Chapter four, Cultivation of Cacti pp. 88,89
9. Kelaidis G, Hardy Succulents pp. 129,130. Storey Publishing
I can't vouch for the links, I copied them from the journal.
It helps if I include the info...
1. Burleigh M./ Elton Roberts, and D Russell Wagner, Acidic Solutions, adjusting water’s pH improves plant growth, Cactus and Succulent Journal 80, (5) Sept/Oct 2008, pp. 245-250
2. Brown R. Growing Cacti and Succulents for the Beginner – “Are you buying steak or getting hamburger?” Part 8 CSSA Newsletter 68, (2), Mar/Apt (sic) 1996 pp. 25, 28, 29
3. Arndt SK, Wolfgang Wanek and Gunther Hoch, Andreas Richter and Marianne Popp, Flexibility of nitrogen metabolism in the tropical C3-crassulacean acid metabolism tree species Clusia minor http://cat.inist.fr/?aModele=afficheN&cpsidt=13712439
4. Fernandes J, Ricardo M Chaloub and Fernanda Reinert, Influence of nitrogen supply on the photoprotective response of Neoregelia cruenta under high and low light intensity
http://www.publish.csiro.au/paper/PP01209
5. Ruan J, Gerendas J, Hardter R and, Sattelmacher B, Effect of nitrogen form and root-zone pH on growth and nitrogen uptake of tea (Camellia sinensis) plants. Institute for Plant Nutrition and Soil Science, Kiel University, Kiel, D-21098, Germany. jruan@mail.tricaas.com
http://www.ncib.nlm.nih.gov/pubmed/17204540
6. Britto DT, Herbert J Kronzucker NH4+ toxicity in higher plants: a critical review, J. Plant Phiol. 15+.567-584 (2002) Urban & Fischer Verlag
http://www.urbanfischer.de/journals/jpp
7. Buxbaum F, Cactus Culture Based on Biology, pp. 34-44 Blanford Press, London, 1958
8. Brown R, The Cactus Family Timber Press, Portland, Cambridge Chapter four, Cultivation of Cacti pp. 88,89
9. Kelaidis G, Hardy Succulents pp. 129,130. Storey Publishing
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.
Tim
Tim
But the tree is a C3 CAM plant!
I'll keep you posted on my experiences. I did the acidifying water thing for a couple of years then stopped for about 9 months. I was getting a lot of calcium/bicarbonate/salt encrustation with the VERY hard tap water I have.
I was getting excellent growth with most plants though.
With the new regimen I'm lowering the pH farther than in the past.
I'm going to have to get serious about the hard water at some point.
I'll keep you posted on my experiences. I did the acidifying water thing for a couple of years then stopped for about 9 months. I was getting a lot of calcium/bicarbonate/salt encrustation with the VERY hard tap water I have.
I was getting excellent growth with most plants though.
With the new regimen I'm lowering the pH farther than in the past.
I'm going to have to get serious about the hard water at some point.
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.
Tim
Tim
"C3 CAM" is a meaningless term. C3 and CAM are completely different and incompatible. They do not occur at the same time in the same place. CAM is a C4-based metabolism.
Clusia minor changes its behaviour so that it uses C3 for maximum growth when water is generous, and switches to CAM to preserve water during drought. This type of switch between two completely incompatible metabolisms requires several weeks and is typically used by plants in climates with reliable wet and dry seasons. Obviously when experimenting on this plant you have to be very careful to see which metabolic state it is in, almost like working with two completely different species that you can't tell apart visually.
Most facultative CAM succulents switch between two different forms of CAM, one being the standard form for water preservation. The other form, often referred to as weak CAM, gives growth similar to C3 but using the CAM C4 chemical processes. Strangely, the stomata are open during the day and carbon dioxide is taken up continuously, and they are closed at night when carbon dioxide from respiration is fixed into malates. Night-time fixation is tiny compared to daytime fixation. This type of metabolism switch can be performed literally overnight, and then back again, just by changing the times that the stomata open,
A few succulents do show C3/CAM switches but usually just once per lifetime. Several annual mesembs use C3 during early rapid growth which occurs during the winter rainy season, then switch permanently to CAM when the rains end, at which point they start to flower. A very tiny number of plants have been shown to use two different metabolisms simultaneously, for example a Portulaca which uses CAM in its leaves and non-CAM C4 in its stems. This isn't entirely understood, since C4 is somewhat more water efficient than C3 but still an order of magnitude or more less efficient than CAM. It is primarily a high-growth metabolism for hot sunny climates with moderately low rainfall, common among grasses.
CAM in bromeliads is interesting because it is thought to be used where daytime carbon dioxide takeup is prevented by too much water on the leaves. They have been extensively studied because their metabolisms are generally quite flexible in response to conditions, making extensive use of morning and evening to increase their carbon dioxide takeup when stricter CAM plants would have shut down already to preserve water.
Clusia minor changes its behaviour so that it uses C3 for maximum growth when water is generous, and switches to CAM to preserve water during drought. This type of switch between two completely incompatible metabolisms requires several weeks and is typically used by plants in climates with reliable wet and dry seasons. Obviously when experimenting on this plant you have to be very careful to see which metabolic state it is in, almost like working with two completely different species that you can't tell apart visually.
Most facultative CAM succulents switch between two different forms of CAM, one being the standard form for water preservation. The other form, often referred to as weak CAM, gives growth similar to C3 but using the CAM C4 chemical processes. Strangely, the stomata are open during the day and carbon dioxide is taken up continuously, and they are closed at night when carbon dioxide from respiration is fixed into malates. Night-time fixation is tiny compared to daytime fixation. This type of metabolism switch can be performed literally overnight, and then back again, just by changing the times that the stomata open,
A few succulents do show C3/CAM switches but usually just once per lifetime. Several annual mesembs use C3 during early rapid growth which occurs during the winter rainy season, then switch permanently to CAM when the rains end, at which point they start to flower. A very tiny number of plants have been shown to use two different metabolisms simultaneously, for example a Portulaca which uses CAM in its leaves and non-CAM C4 in its stems. This isn't entirely understood, since C4 is somewhat more water efficient than C3 but still an order of magnitude or more less efficient than CAM. It is primarily a high-growth metabolism for hot sunny climates with moderately low rainfall, common among grasses.
CAM in bromeliads is interesting because it is thought to be used where daytime carbon dioxide takeup is prevented by too much water on the leaves. They have been extensively studied because their metabolisms are generally quite flexible in response to conditions, making extensive use of morning and evening to increase their carbon dioxide takeup when stricter CAM plants would have shut down already to preserve water.
--ian