Fertilizers explained (2-part presentation) -- with 6/2023 update

Discuss repotting, soil, lighting, fertilizing, watering, etc. in this category.
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Re: Fertilizers explained (2-part presentation)

Post by Minnesota »

zpeckler wrote: Fri May 05, 2023 11:42 pm
jerrytheplater wrote: Fri May 05, 2023 10:38 pm
zpeckler wrote: Fri May 05, 2023 5:11 pmdo you have an opinion on amending the growing medium with some pelletized dolomitic limestone and gypsum for those species that grow on limestone in habitat?
I'm not Steve, but I do have a comment on Pelletized Limestone. Those pellets are comprised of very finely ground limestone held together loosely by a water activated binder. Once it gets wet it falls apart. Then the particles are very easily dissolved compared to granules of gypsum. The gypsum granules will dissolve much more slowly and release the calcium slowly. Better choice than the pelletized limestone.
Thanks a bunch for the advice, Jerry. I've got a bunch of the limestone and gypsum on hand because every freaking year my hot peppers get blossom end rot, so I gotta amend the soil like crazy. The fertilizer regimen described in this thread is working really well for my cacti, and I'm reluctant to try and fix something that ain't broke, but I would like to try and mimic habitat as much as I can. Maybe I'll try and find some limestone gravel, if that's a thing.
Hi, z--

If you don't find other resources, when I went lookng, I found crushed limestone rock on eBay for train enthusiasts. It came as a mixed crush, 2-12 mm stones, with an even coloration for creating toy train model courses/tracks. Worked great for my smaller needs. Take a look if you're coming up short elsewhere.

--bret
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Re: Fertilizers explained (2-part presentation)

Post by jerrytheplater »

zpeckler wrote: Fri May 05, 2023 11:42 pm
jerrytheplater wrote: Fri May 05, 2023 10:38 pm
zpeckler wrote: Fri May 05, 2023 5:11 pmdo you have an opinion on amending the growing medium with some pelletized dolomitic limestone and gypsum for those species that grow on limestone in habitat?
I'm not Steve, but I do have a comment on Pelletized Limestone. Those pellets are comprised of very finely ground limestone held together loosely by a water activated binder. Once it gets wet it falls apart. Then the particles are very easily dissolved compared to granules of gypsum. The gypsum granules will dissolve much more slowly and release the calcium slowly. Better choice than the pelletized limestone.
Thanks a bunch for the advice, Jerry. I've got a bunch of the limestone and gypsum on hand because every freaking year my hot peppers get blossom end rot, so I gotta amend the soil like crazy. The fertilizer regimen described in this thread is working really well for my cacti, and I'm reluctant to try and fix something that ain't broke, but I would like to try and mimic habitat as much as I can. Maybe I'll try and find some limestone gravel, if that's a thing.
Besides Minnesota's suggestion of model RR ballast, also look for a marine aquarium substrate called Aragonite. An example is CaribSea Special Grade Reef Sand with a grain size of 1-2 mm. https://caribsea.com/marine-substrates/
Jerry Smith
Bloomingdale, NJ
45 inches (114 cm) rain equivalent per year, approx. evenly spread per month
2012 USDA Hardiness Zone 6b: -5F to OF (-20C to -18C) min.
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Steve Johnson
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Fertilizers explained (6/2023 update)

Post by Steve Johnson »

-------------------------------------------------------------------------------------------------------------------------
Note: I posted "Fertilizers explained" on 1/21/23. If you haven't seen it yet, go there first...

viewtopic.php?t=47603

... then come back for the update.
-------------------------------------------------------------------------------------------------------------------------
This just in.
Steve Johnson wrote: Sun Jan 22, 2023 6:53 amMy fert of choice is Dyna-Gro All-Pro 7-7-7, so we'll use it as an example. The guaranteed chemical analysis:

Image

Available N = 7%
P2O5 = 7% x 0.436 = 3.052% elemental P available to the plant
K20 = 7% x 0.83 = 5.81% elemental K available to the plant

The true NPK value for the 7-7-7 is 7-3.052-5.81. Using N as a constant of 1, the NPK ratio is 1:0.44:0.83 -- the balance between N and P is pretty much ideal...
Actually, no -- thanks to more recent information coming from MikeInOz, the acceptable range for P is 0.25-0.35. Go any higher, and problems will slowly creep up on you over time. Ever since I started using the 7-7-7 in 2012, those problems were creeping up on me too, and I didn't notice until I saw most of my older cacti exhibiting these symptoms last year:
  • Growth slower than normal for the species.
  • Unnaturally pale skin color (Mo deficiency has something to do with it too).
  • Inhibited flowering or no flowering at all.
When Dyna-Gro decided to discontinue the All-Pro 7-7-7, it turned out to be a blessing in disguise as I replaced it with General Hydroponics FloraMicro 5-0-1 and FloraBloom 0-5-4 liquid fertilizers. Only problem there -- P is still a little too high in relation to N if we're supplementing it only with Potassium sulfate.
Solution -- include Ammonium sulfate. (Truth be told, I could've done the same thing if Dyna-Gro was still selling the 7-7-7.) This is the recipe I'm using now:

Image

What we're talking about here is a balancing act, so if your fert's NPK is out-of-balance, you can correct it with the addition of Ammonium sulfate and Potassium sulfate to strike the right balance in your watering solution. How much you'll need in an Ammonium sulfate-Potassium sulfate stock solution, and how much of the stock solution should go into the watering solution depends on your fert. The calculations involved aren't difficult, although if you're math-challenged and you can use some help, please feel free to PM me. Once I run the numbers, I'll get back to you with the right recipe and instructions.
Steve Johnson wrote: Sun Jan 22, 2023 6:53 am...here's a table showing the proper dilutions for ferts with 5%, 7%, 10%, and 20% N in teaspoons per gallon and milliliters per liter. Note: The table applies only to liquid fertilizer concentrates. Unfortunately, dilutions using dry ferts are beyond my pay grade!
Image
They were beyond my pay grade, but not anymore. The tricky part is knowing that dry fertilizers need to be diluted by mass (weight), not volume as we'll do with liquid ferts. Another tricky part -- calculating grams per gallon or grams per liter for the proper dilution. Here are the tricks:

Image

A couple of things come to mind:
  • Nitrogen is the benchmark indicator to follow, and you won't be overfeeding your cacti if you keep it below 90 ppm in your watering solution. If you prefer growing your cacti in the "hard" style, aim for 40 ppm. (Anything below 30 ppm is putting them on a starvation diet! The same applies to growers who think it's a good idea to feed their cacti only once or twice a year.)
  • Compared to liquid fertilizers, dry ferts give you more precise control over how much you're diluting.
Given the choice between liquid and dry, I don't know if there's any particular advantage to choosing a dry fert. However, for growers who find that liquid ferts are too expensive (or they can't find ones that are suitable), dry is their only choice -- in which case, they'll be better off if they dilute by weight rather than volume.
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_Scotty
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by _Scotty »

First off thank you for a wonderful nutrient breakdown and detailed instructions here!

I’m brand new to this forum, been growing cacti seriously for 5 years now and learning a lot! I joined because I’ve been struggling with finding a replacement for the Dyna-gro 7-7-7 and stumbled upon this very informative post.

My current regimen is
Per gallon
1/2 TSP 7-7-7
1/4 TSP CALMAG
1/8 TSP k2so4

If I’m understanding correctly your regimen is
Per gallon
1/2 TSP FloraMicro
1/2 TSP FloraBloom
1/4 TSP Sodium Molybdate
1/4 TSP CALMAG
7 Fluid Ounces of Stock Solution
And stock solution is k2so4 and H8N2O4S that is made separately in a gallon container with distilled or rainwater.

Also could you just add K2 and H8 as a dry feet to the gallon mixture and how much TSP of each would that be?

Thank you again!
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by Steve Johnson »

You're welcome, Scotty!
_Scotty wrote: Wed Jun 07, 2023 12:45 am Also could you just add K2 and H8 as a dry feet to the gallon mixture and how much TSP of each would that be?
If I understand your question correctly, here's the answer...

Theoretically, we could put the right amounts of Ammonium sulfate and Potassium sulfate powders directly into the watering solution. In reality, that means having to do it every time you're preparing to water and fertilize your plants, and besides that, the powders take some time to dissolve. It's easier to make a gallon of stock solution (measure the powders once), then dispense the recommended amount of stock solution per gallon of watering solution. When the stock solution is used up, all you have to do is make another gallon. In my case, I have a small collection, and a gallon of watering solution lasts for the better part of the growing season. A couple of hints for you:
  • If you don't already have one, buy a digital scale measuring down to .01 gram for the Ammonium sulfate and Potassium sulfate powder going into your stock solution. (You'll also need it to measure the Sodium molybdate for a Sodium molybdate stock solution.) This is the scale I got from Home Science Tools:

    https://www.homesciencetools.com/produc ... g-x-001-g/

    Not that expensive, and way better than the cheapo scales we get on Amazon. Measuring accuracy for dry ferts and supplement powders is very
    important -- you won't get the accuracy you need with measuring spoons.
  • Liquids are a lot easier to measure accurately with measuring spoons, so you're set with 1/2 tsp. FloraMicro, 1/2 tsp. FloraBloom, 1/4 tsp. CalMag, and 1/4 tsp. Sodium molybdate stock solution. Problem with 7 fluid ounces of Ammonium sulfate-Potassium sulfate stock solution per gallon of watering solution -- the measuring cups we get at the store measure in 2-fluid ounce increments. Guessing between the 6-ounce and 8-ounce lines to find 7 fluid ounces ain't accurate is it? Silly me, this is really what we US growers should be doing:

    For the Ammonium sulfate-Potassium sulfate stock solution, dilute 5.5 grams Ammonium sulfate powder and 7.5 g Potassium sulfate powder per gallon of distilled water or rainwater. That will give you a dilution of 6 fluid ounces per gallon of watering solution -- no guesswork about putting the right amount in.
I'll revise the GH spreadsheet accordingly. If I need to post it again at a later time, this will make things a little easier for our members.
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by _Scotty »

Oh going to order one of those scales for sure, sounds like the stick solution is the way to go!

Last question the sodium molybdate is 1.44g or .5688g per gallon for the stock solution?

Thank you again!
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by Steve Johnson »

_Scotty wrote: Wed Jun 07, 2023 3:23 pm Last question the sodium molybdate is 1.44g or .5688g per gallon for the stock solution?
1.44 g per gallon or 0.72 g per half-gallon. Just doing some quick math -- at the rate I'm going, the half-gallon of sodium molybdate stock solution I made back in March will last me about 30 years! Depending on the size of your collection and how often you fertilize when you water, you could go even smaller (maybe I should've done that?):
  • 0.36 g to make a quart of sodium molybdate stock solution.
1/4 tsp. stock solution per gallon of watering solution stays the same regardless of how much stock solution you made. And the nice thing is that it lasts forever (in other words, no expiration date).
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by _Scotty »

Oh awesome thank you!

Yeah so a little over 3000 doses at 1/4 tsp per gallon haha, might stick with the pint size although if it lasts forever why not!
Assuming the K2 H8 stock solution last awhile as well?

Really hoping this can get my cacti to flower again, really struggled with getting any of them flowering this year
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by Steve Johnson »

_Scotty wrote: Wed Jun 07, 2023 7:46 pm Oh awesome thank you!
My pleasure! :)
_Scotty wrote: Wed Jun 07, 2023 7:46 pmYeah so a little over 3000 doses at 1/4 tsp per gallon haha, might stick with the pint size although if it lasts forever why not!
Assuming the K2 H8 stock solution last awhile as well?
With regard to the Ammonium sulfate-Potassium sulfate stock solution, there are a couple of limitations:
  • If you live in an area subject to freezes during winter and you keep the stock solution in a garage, outdoor garden shed, etc., it'll freeze too. End result -- potassium salt crystals. This is a nasty surprise for growers who let the Dyna-Gro ferts freeze, and getting those crystals back into solution is a pain in the you-know-what. I got stuck in that situation myself with a gallon of the Dyna-Gro 7-7-7, and I've been keeping it in my kitchen ever since. (A moot point now since I don't use it anymore.) If you keep the stock solution safely stored indoors, you won't have to worry about winter freezes.
  • If you expose the stock solution to light for extended periods of time, this can encourage algae to form on the inside walls of the jug. However, this does take a long time -- the first time I saw it was about 8 or 9 months after I made my first gallon of stock solution. Plenty of natural light in my kitchen, and oddly enough the algae appeared in winter. I solved the problem by keeping it in a closet over the fall and winter. Do that and yes, the Ammonium sulfate-Potassium sulfate stock solution lasts until it runs out and you need to make more.
_Scotty wrote: Wed Jun 07, 2023 7:46 pmReally hoping this can get my cacti to flower again, really struggled with getting any of them flowering this year.
Lack of flowering could be a symptom of deeper problems, and it's why I came to the conclusion that "expert" cactus growers recommending higher-P fertilizers are recommending exactly the wrong thing. Of course we can talk about lower-P ferts, but this means nothing without putting a number to it. Just to review -- using N as a constant of 1 in the NPK ratio, the acceptable range for P is 0.25-0.35. Scotty, you and I have it nailed with our GH ferts and supplements, so I think you'll enjoy better results in the near future.
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by _Scotty »

Ok perfect so I’ll just keep them in a box in my living room. That should keep them dark and in the proper temperature.

Yeah, they’ve been growing just fine and repotting this year all had pretty solid roots. Just the past two years flowering has declined dramatically, except for the Gymnocalyciums which are in dirt and mineral mix which makes sense why they are still flowering just fine.

I am excited to get this going, I ordered all the stuff so should be good to go in a week or so! Thank you again for taking the time to respond and write all this out!
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by CactiJim »

When we water our cacti using this fertilizer solution, is it ok to just water the cacti and drench them or should we only try to water the substrate and avoid drenching the body of the cactus? Asking because I have about 90 individually potted cacti in 3, 1020 trays and that would be quite the cumbersome task.
-Jimmy, Phoenix, AZ
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by jerrytheplater »

This fertilizer solution is dilute enough that it will not hurt if it gets on the plants. Now, there may be some plants that are extraordinarily sensitive and would be harmed, but I am not aware of them. Maybe those with a waxy bloom that can get rubbed off?

I know my friend that is a commercial grower of garden bedding plants fertilizes this way. Impossible to get the fertilizer water only at the surface of the growing media. He uses a more concentrated solution of fertilizer than the method in this thread presents. No damage, no pampered plants.
Jerry Smith
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45 inches (114 cm) rain equivalent per year, approx. evenly spread per month
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by CactiJim »

Jerry, thanks! Good to hear. I’m just waiting for my scale to arrive and it’s feeding time.
-Jimmy, Phoenix, AZ
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by Steve Johnson »

I water all of my cacti from the top just like they're being rained on. I know that some growers prefer to water their plants from the bottom, but IMO it's unnecessarily "labor intensive", and I could never see any particular advantage to doing it when I tried watering my cacti from the bottom many years ago. The amount of nutrients in the watering solution is so low that the dilute ferts and supplements won't harm waxy-skinned cacti. The only thing to be concerned about there is if growers spray their plants with alcohol to kill pest mites.
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Re: Fertilizers explained (2-part presentation) -- with 6/2023 update

Post by CactiJim »

Ok fellow cacti comrades. I finally did my first watering with the fertilizer. I’m super excited to see the results. One question, however; I ended up using 4 gallons of this solution to water and thoroughly drench my plants. And it was time consuming to make 2 gallons twice.

Do you guys this it would be ok to make 5 gallons of this solution and put it in one of those 5 gallon water jugs and leave it in my house somewhere until I’m ready to use it? Or will the nutrients settle and combine somehow and mess up? I don’t think it’ll stay around for long especially during this growing season. Probably won’t make solution during winter.
-Jimmy, Phoenix, AZ
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