Hydroponics Drain to Waste windowsill/patio cactus growing

[jp29]

I have formalized my current cactus growing methodology on a web page. Please visit it using the link in my signature block - all feedback is appreciated.

[BarryRice]

Cool.

[Ron43]

Excellent info. Thanks for posting.

[jp29]

Excellent info. Thanks for posting.

Thanks, Ron.

[jp29]

I want to thank those who have responded to my request for feedback - mostly via e-mail and Forum(s) postings. I received many excellent suggestions. I have incorporated some of them into this revised edition of my web page along with the addition of updated information and several more photos.

For those who would like to try, or experiment with, this methodology: what I describe is the way I have adapted it -- you would have to adapt it to suit your own environment and growing conditions.

[Steve Johnson]

Hi James,

I reviewed your webpage, and in general it looks like a good presentation. However, I'm still concerned that you may not be acidifying your water as much as you should. Since I recently received my new Milwaukee Instruments pH 600 meter, now would be a good time to compare it against the General Hydroponics colorimetric pH kit which I also purchased just to give us a fair test. (I believe that's the same test kit you're using.) Okay, here we go. To review, the MI meter needs proper calibration and maintenance so it stays accurate. Being "Mr. OCD", I have no problem keeping this routine up, although while it's neither difficult nor complicated, I totally understand why it may not be worth the bother for many. But I digress...

I watered my cacti last night, so today is a "live fire" test with 1 gallon of my tap water and no fertilizer. The water wasn't quite as hard as I've seen before, testing at a pH of 7.5. After gradually increasing the amount of vinegar I added, I was able to determine that 4 1/2 tsp. brought the pH of the water down to 5.0. Now here's what the General Hydroponics test kit has to say:



As we can see, the colorimetric indicator is testing too low, and there's a big difference between 4 and 5. If the target for your final pH is 6, you'll need to compensate for this discrepancy by adding more vinegar until the indicator tests at 5. Unfortunately these color charts won't give you the kind of decimal point accuracy you'll find with something like the MI meter, although I'm not sure if you need to be all that precise about it. My fert lowers the pH by .7, so when I add 1 tbsp. of vinegar, the final pH is 5.5. Since your water is harder than mine, I don't think you'd go wrong by upping your vinegar to 1 tbsp. per gallon (maybe a little more), although you'll definitely want to test your watering solution first. Also, because water hardness tends to fluctuate, testing your water once a month is a good idea. With that said I've gotten kinda lazy about it, but only because I've been at this long enough to know the seasonal fluctuations coming through my local water system.

By the way -- if you know for sure that your pumice has a pH of 7.4, that's not neutral, but alkaline. I captured the runoff from some of my pots last night and tested the water with the meter. Interestingly enough, it raised the pH by .2, which indicates that pumice is indeed slightly alkaline. I'll have another crack at the slurry test next weekend, then I can find out if the pH changes after a day or two of keeping my pumice/DG mix in water. Whether it means anything or not I don't know, but we'll find out.

[jp29]

Thanks for your input, Steve.

Do you remember this from a previous post? ....................

.......... I believe what you're talking about is a colorimetric indicator dye kit. Easily available online and at hydroponic supply stores. Unfortunately we have a problem there. A little over 2 years ago, I did a fair amount of comparison testing with colorimetric indicators, pH test strips, and a digital pH meter. My meter of choice has been a Milwaukee Instruments pH 600 (rugged and very reliable, although it needs to be properly calibrated to maintain accuracy. No big deal, however, plus the meter is fairly inexpensive). Test strips are pretty much useless. Indicator kits test at a significantly lower pH compared with the meter ...........

Extract from CACTUS CULTURE BASED ON BIOLOGY - Dr. Franz Buxbaum (translated by Vera Higgins), Blandford Press, 1958.

Chapter 4 - Page 38:

" .......... The most exact measurements of soil reaction values are obtained electrometrically and are very elaborate, but it is sufficient for our purpose to use a colorimetric method that any child could carry out in a second .........." (relating to soil reaction and the chemical requirements of the soil) - and he goes on to illustrate the slurry method of testing the soil pH using the colorimetric tester in fig 7 which occupies all of page 39.

To continue ..........

.......... Since I recently received my new Milwaukee Instruments pH 600 meter, now would be a good time to compare it against the General Hydroponics colorimetric pH kit which I also purchased just to give us a fair test ...........

I think you are getting far too wrapped up into Ph testing accuracy, Steve. There are simply too many fluctuations in pH values throughout any given day to require that degree of accuracy. That is why Dr. Buxbaum makes the statement that he does. But just to satisfy your curiosity, I will have Dr. Wheeler run some comparison tests in his Laboratory.

.......... However, I'm still concerned that you may not be acidifying your water as much as you should ..........

Well, you know the old saying, Steve: "The proof of the pudding is in the eating". My cacti have grown for many years, and continue to grow at present, healthy and robust, bearing bountiful crops of flowers and fruit - I can't recall the last time one succumbed to rot or disease.

.......... I don't think you'd go wrong by upping your vinegar to 1 tbsp. per gallon (maybe a little more), although you'll definitely want to test your watering solution first. Also, because water hardness tends to fluctuate, testing your water once a month is a good idea. With that said I've gotten kinda lazy about it, but only because I've been at this long enough to know the seasonal fluctuations coming through my local water system ...........

I no longer use vinegar - I use the acidifier solution that comes as part of the General Hydroponics kit. Testing the pH of the water alone is only required when you are going to use it to flush excess nutrients from the growing medium (and in my case to final rinse the pumice after I have washed it to remove dust (which I hope you are doing with your DG, Steve) otherwise, you should really be testing the pH of the nutrient solution.
-

.......... By the way -- if you know for sure that your pumice has a pH of 7.4, that's not neutral, but alkaline ...........

You probably missed this photo caption:

The pumice described above after washing it to remove dust
I perform a final rinse wash using my acidified city tap water

I then do a slurry test and adjust the pH

[Steve Johnson]

I have a bad habit of getting wrapped up in a lot of detail that's not interesting to anyone else. I really stepped in it this time, so I'll shut up about acidification from here on out.

[jp29]

I have a bad habit of getting wrapped up in a lot of detail that's not interesting to anyone else. I really stepped in it this time, so I'll shut up about acidification from here on out.

Please do not do that, Steve - you do contribute so much thought provoking information.

[Brunãozinho]

Hi James, thanks for sharing all this.

On your page you mention you use a 30% shade cloth during the active growing period.
Some of the plants that you grow take the hot sun from Bahia all day long, some even grow on stones that are of a light gray color, wich I believe can even increase the incidence of light on the plant.
I grow some cacti from Bahia too, the climate conditions here are quite similar to their habitat's. I have wondered if I should test using a shade cloth to see how the plants would react. Some of my plants take full sun all day, others are on the shade during late morning and early afternoon.

I know the harsh sun can mean a lot of stress for some cacti. So how is your cultivation experience in Arizona without shade cloth for those plants, do you notice much difference?
Can the Arizona sun stress them too much? Or is it just a way you find to reduce the stress for the plants so that they grow better?

[Brunãozinho]

I have a bad habit of getting wrapped up in a lot of detail that's not interesting to anyone else. I really stepped in it this time, so I'll shut up about acidification from here on out.

Hey Steve, I too believe that water properties (PH and others) are so very important in cactus cultivation. I notice how better my plants grow when watered with good and fresh rain water, even the ones that haven't been repoted for quite some time, growing on old soil mixtures. I'm always trying to learn more about acidification and all your detailed posts on this forum have been very helpful, I haven't commented on them since I consider my experience to be still quite reduced.

[jp29]

Hi James, thanks for sharing all this ...........

You are welcome, Bruno - and I thank you in turn for your input.

.......... On your page you mention you use a 30% shade cloth during the active growing period.
Some of the plants that you grow take the hot sun from Bahia all day long, some even grow on stones that are of a light gray color, wich I believe can even increase the incidence of light on the plant.
I grow some cacti from Bahia too, the climate conditions here are quite similar to their habitat's. I have wondered if I should test using a shade cloth to see how the plants would react. Some of my plants take full sun all day, others are on the shade during late morning and early afternoon ........... I know the harsh sun can mean a lot of stress for some cacti. So how is your cultivation experience in Arizona without shade cloth for those plants, do you notice much difference? Can the Arizona sun stress them too much? Or is it just a way you find to reduce the stress for the plants so that they grow better?

I have done quite a bit of experimenting with shading schemes for my cultivated cactus over the years and I don't think I have achieved the ideal situation for many of them yet. I think most of us grow our plants in very unnatural conditions viz. in root system restrictive containers that can become extraordinarily overheated - even in mild climates and in greenhouses - especially during summer months.

Back to shading: when I grew my Woolworth-bought cacti on a south facing windowsill in northern England (Burnley, Lancashire - eleven years starting in 1939) putting them outside in full sun (after a brief acclimating period) during the summer. I do not recall any sunburning problems, but the summer sunshine in Lancashire is pretty anemic compared with the US desert south west.

When I grew field collected cacti (pre CITES) in south Texas (San Antonio - eleven years) - even such plants as Ariocarpus from open sun drenched desert areas - they quickly sunburned in pots, or even in the ground (of course, their root systems had been extensively trimmed). I didn't own a greenhouse, so I took to growing them in the broken shade of mesquite trees.

Growing cacti in Japan (approx. 20 miles north of Tokyo - three years - occasional windowsill growing) was pretty much the same as growing them in northern England.

Growing cacti in the high desert of southern California (Victorville - four years) was much the same as growing them in south Texas except it was much more arid and the winters were colder. Gil Tegelberg became my mentor and I took heed of his advice to grow my cacti as "hard" as possible to insure good body coloration, a healthy epidermis, strong spination and optimum flowering/fruiting - at the same time protecting them from sunburn due to their often overheated root systems confined in small pots. He grew his cacti and succulents (except for his seed growing enterprise) under 30% shade cloth, asserting that was the optimum shading necessary in order to achieve his goals. I adopted his philosophy and have followed it ever since.

Growing cacti in central Florida (Tampa - two years) was similar to south Texas except for the often stifling humidity and almost daily summer rain storms - I was now growing my potted cacti under 30% shade cloth exclusively - my globular cacti, even Copiapoa's - swelled up like balloons.

I have grown my small cacti (housed in appropriately small containers) here in Tucson (cactus growing heaven) under 30% shade cloth for the past forty five years or so with great success. They do indeed grow well and flower and fruit reliably. I also grow some mature cacti (mostly Pilosocereus, Melocactus and Discocactus) in large pots, in full sun, in my front garden patch. They are well acclimated but even so I get nervous when I perceive what I believe is some epidermal blanching and throw a piece of shade cloth over "stricken" plants for a few days. One big advantage in growing under shade cloth (versus in a greenhouse) is that the excellent air circulation seems to prevent scorching - at least I have not experienced any sunburn - even under our ferocious Arizona summer sun - on my small container grown plants. Another advantage is that nature waters them for me through the shade cloth - and I know they benefit enormously from natural rain water.

The years growing in each place are approximations because I can't remember all the dates precisely.

I should mention that I have no formal training in botany or horticulture and that I base my growing techniques on experience, reading (well regarded and/or accepted in the C&S community) literature and interchange of ideas/information such as that available through personal association with other enthusiasts and discussion groups such as this one.

I think the answers to shading requirements for your plants are like most such answers, Bruno - they depend on your own environment and growing conditions (and your personal approach to cultivation of cacti in general).

Well, I am pretty much exhausted after writing all this and I must be off to another (interminable) Doctor appointment. I will undoubtedly have to edit this post several times - I forget so many things these days.

[K.W.]

James, dear Sir,

I read all your posts with an undivided interest and getting more and more respect.
Our theme here are cacti, with you they were there for life.

A la bonheur!

I wish you all the best, my respect and best wishes!

K.W.

PS all my plants (5 to 6.000) are growing in pumice, water from above, fertilizer and acetic acid at every watering, ph 5,5. I think they're fine, 95%.
And of course, shading, even here in Central Europe. When I see how much dirt is on Ariocarpus in the habitat, they have also their shading. . .

[jp29]

James, dear Sir,

I read all your posts with an undivided interest and getting more and more respect.
Our theme here are cacti, with you they were there for life.

A la bonheur!

I wish you all the best, my respect and best wishes!

K.W.

Thank you very much for those most kind words!

.......... PS all my plants (5 to 6.000) are growing in pumice, water from above, fertilizer and acetic acid at every watering, ph 5,5. I think they're fine, 95%. ..........

My goodness, that is amazing My hat is off to you for a truly fine accomplishment. I have been checking your set-up in your continuing thread Every day new flowers in the greenhouse in Köln in the Member topics section - very nice indeed!

.......... And of course, shading, even here in Central Europe. When I see how much dirt is on Ariocarpus in the habitat, they have also their shading. . .

I had never thought of that before. Once again, thank you.

[Brunãozinho]

That's some valuable information, it's great to get to know more from the reports of experienced growers and I'm thankful to those who share their knowledge.