Nice to meet you all from Indonesia (and an overview on my plant journey)

[Steve Johnson]

Alright, I'll get those ferts first. I'll check if I have time this weekend or next weekend to do this entire project. Here are my candidates:

https://saprotan-utama.com/wp-content/u ... us2020.pdf
https://meroketetapjaya.com/files/uploa ... keSOP@.pdf

Let me know if there's any change in dilution of these ferts according the percentages of elements provided by the ferts' distributors.

No change -- go with the dilutions I gave you. Nice thing about the powders -- level teaspoons (or in your case, quarter-teaspoons) give you consistent dosages every time.

Also regarding water hardness, I'll get the test kit some time later (hopefully within this month) or going to Flona again to get info about this. In the meantime, I'll try to get any information regarding water hardness result in other region for a reference (regions within Java).

I think hardness will be fairly consistent across regions, so that's a good idea. The big question -- when you add gypsum to your pots, will there be enough Ca and Mg in your tap water to give you the right Ca-Mg balance, or should you add a little magnesium sulfate (good old Epsom salt) to your watering solution? When I PM'd my questions to Mike, he gave me a ppm number for that. However, best if we don't jump to conclusions before we get some data on your tap water's hardness levels.

[Steve Johnson]

Hi Adi,

Based on his many years of experience, MikeInOz recommends 1-2 grams gypsum granules per liter of potting medium -- 1/8 teaspoon will give you something in between 1 and 2 grams due to the air spaces among granules. If you heap it a little bit, that should give you 2 grams. Now here's the tricky part...

Different pot sizes have different volumes. I'll give you some examples:

• 12 cm x 12 cm round pot = 1.1 L, square pot = 1.7 L

• 10 cm x 10 cm round pot = 0.6 L, square pot = 1 L

• 8 cm x 8 cm round pot = 0.3 L, square pot = 0.5 L

You'll need to estimate the volume of each pot, then estimate the amount of gypsum you should add per pot. We don't need to be precise, and in all cases you'll be adding a relatively small amount of gypsum granules as a top dressing on your pots. Replenish by applying new gypsum granules once a year. Perhaps not easy the first time you do it, but when you develop a feel for how much goes onto each pot, you won't even have to think about it.

[Wiandry Adi]

Hi Steve,

I've visited Flona again and asked some folks - esp. hydroponic growers - regarding Jakarta's water hardness scale and how to measure them. Here are all what I got:

• None of them have ever scaled their water hardness level, unfortunately. That, until one of the vendors said they knew that we, people living in Jakarta, have hard tap water, though they didn't specify how hard it is. All they know is that it's hard enough to clog taps and pipes if not taken care of properly

• Said vendor also made AB mix fertilizer, a fertilizer that I'm still learning about; said fertilizer contained neither calcium nor magnesium, and they stated based on their experience, adding both of them are somewhat unnecessary and they are aware, too, of formation of gypsum had they mixed cal-mag into their fert mixes

• Some stated that as long as a water have slightly neutral to neutral pH, water hardness is not of a concern, while others gave me few ways to measure water hardness if really necessary, such as with titration (using the apparatus Jerry has listed once) and using soap (more foams = less hard and vice versa)

I also looked on other regions' water hardness scale. I found one from Surabaya, a city about hundreds of kilometers away. Please note Jakarta and Surabaya have lots of similarities as by being port cities located in a lowland, coastal region (though there are small differences, the resemblances are striking nonetheless. I've been there several times).

Here's where the test results for said city: https://www.pdam-sby.go.id/read/hasil-p ... alitas-air (the part we're into is at the number 8, "Kesadahan")

Based on the results and some of the outtakes from my visit, I assume Jakarta has hard water. I mean, clogged pipes and taps are one of the more common household problems we often find here and when that hydroponics vendor said that, it's hitting home.

Though I'm not sure how hard (which again, requires lab test), according to this water hardness scale (https://www.researchgate.net/figure/Gra ... _270280257), it's on the Very Hard scale. Also, this may explain why in some times I was drenched in rainwater, it felt kinda better.

Also,

Hi Adi,

Based on his many years of experience, MikeInOz recommends 1-2 grams gypsum granules per liter of potting medium -- 1/8 teaspoon will give you something in between 1 and 2 grams due to the air spaces among granules. If you heap it a little bit, that should give you 2 grams. Now here's the tricky part...

Different pot sizes have different volumes. I'll give you some examples:

• 12 cm x 12 cm round pot = 1.1 L, square pot = 1.7 L

• 10 cm x 10 cm round pot = 0.6 L, square pot = 1 L

• 8 cm x 8 cm round pot = 0.3 L, square pot = 0.5 L

You'll need to estimate the volume of each pot, then estimate the amount of gypsum you should add per pot. We don't need to be precise, and in all cases you'll be adding a relatively small amount of gypsum granules as a top dressing on your pots. Replenish by applying new gypsum granules once a year. Perhaps not easy the first time you do it, but when you develop a feel for how much goes onto each pot, you won't even have to think about it.

thanks for this info! Now with that I already ordered some of these, I'll kindly wait for other info while my gypsum comes. Though, while the numbers are still not in the clear, I'd go with less amount, maybe like 3-6 granules per small pot and so on. Always be on the safer side, yes?

And now, about the ammonium and potassium sulfate ferts:

They've arrived and I'm crunching the numbers and doing the experiments now, but I have other things going on so I'll post the results by the other day, hopefully this week. For starter: the pH of untreated tap water is still constant: 7.

[Steve Johnson]

...the pH of untreated tap water is still constant: 7.

From HydroFlow U.S.A., this quote gives us some insight:

• "The Scientific Definition of Hard Water
  
  "The scientific definition of water hardness refers to the presence of dissolved ions, mainly of calcium Ca2+ and magnesium Mg2+ which are acquired through contact with rocks and sediments in the environment. The positive electrical charges of these ions are balanced by the presence of anions (negative ions), of which bicarbonate HCO3– and carbonate CO32– are most important. These ions have their origins in limestone sediments and also from carbon dioxide which is present in all waters exposed to the atmosphere and especially in groundwater."

Ca2+ and Mg2+ are the cations that make the Ca and Mg in hard water immediately available for uptake by plants. Since your untreated tap water has a pH of 7, it means that you don't have any bicarbonate or carbonate anions in your water (or at least not enough to worry about). For you this is good news because:

• Your cacti and succulents are getting plenty of Ca and Mg from the hardness in your tap water. Adding gypsum is a nice little bonus, so you can go light on that. I do agree -- better to be on the safe side.

• IMO your Pak Tani, PROVIT Orange, and Multiara GROWER plus the ammonium sulfate and potassium sulfate supplements are doing a marvelous job of acidifying your watering solution, so you won't need to add an acidifier -- not even for your alkaline mix.

Mike said that the water where he lives is the purest in Australia and does not have enough Ca, Mg, or S, so he needs to add them. As for me, I need to acidify because my tap water contains bicarbonate. Lucky you! However, occasionally flushing your pots with pure water should still be standard practice. In regions experiencing fall/winter dormancy, once a year in the growing season is sufficient. Because you live in a tropical region where cacti grow year-round, I'll recommend that you flush your pots twice a year.

And now, about the ammonium and potassium sulfate ferts:

They've arrived and I'm crunching the numbers and doing the experiments now, but I have other things going on so I'll post the results by the other day, hopefully this week.

Just a reminder about the test I'd like you to run:

• Fill one of your 50 liter buckets with tap water, test the pH, and write down the number.

• Dilute all of your fertilizers including the ammonium sulfate and potassium sulfate. Let the watering solution sit for about 10 minutes, then give it a thorough stirring. Test the pH of the watering solution and write down the number.

• Fill a clean glass jar with your watering solution, put a lid on it and let it sit for 7 days. Test the pH, then write down the number.

This tests the pH rebound effect, and you'll need more than 1 day to get an accurate result.

Those are the 3 data points I'm looking for -- pH of the tap water, pH of your watering solution with the diluted ferts, and pH of the watering solution after 7 days in the test jar. When I get the numbers, we'll be able to predict the beginning and ending pH of your mixes going from wet to dry.

[Wiandry Adi]

Well, nice to knowing that my tap water is still on my side then!

About the third step of your proposed experience,

I'd like you to run another pH test, but with a new wrinkle this time:

• Fill one of your 50 liter buckets with tap water, test the pH, and write down the number.

• Dilute all of your fertilizers including the ammonium sulfate and potassium sulfate. Let the watering solution sit for about 10 minutes, then give it a thorough stirring. Test the pH of the watering solution and write down the number.

• The new wrinkle -- fill a clean glass jar with your watering solution, put a lid on it and let it sit for 7 days. Test the pH, then write down the number.

I've done the last step of filling a jar with my solution, put a lid on it, and let it sit. At this moment, I put it at my patio which gets morning sunlight only and it's really bright and sometimes heat comes in. Shall I keep it there just as it is or moving the jar into somewhere cooler and darker?

Also, about flushing my plants, since you proposed it to be twice a year, how long the interval between each flushing should be? I'm thinking once in 6 months, but there may be another... twist! Also also, if rainwater is still scarce - I hope not - may tap water be used? And since it'll be plain tap water, may I add the citric acid just to 'spice' the water up?

[Steve Johnson]

I've done the last step of filling a jar with my solution, put a lid on it, and let it sit. At this moment, I put it at my patio which gets morning sunlight only and it's really bright and sometimes heat comes in. Shall I keep it there just as it is or moving the jar into somewhere cooler and darker?

I don't think heat affects pH. Besides, if the mix in your pots gets heated up (I'm pretty sure it does) and the heat does affect pH, keep your test jar right where it is to approximate the daytime heat levels in your collection. Either way, the test will produce a valid result.

Also, about flushing my plants, since you proposed it to be twice a year, how long the interval between each flushing should be? I'm thinking once in 6 months, but there may be another... twist! Also also, if rainwater is still scarce - I hope not - may tap water be used? And since it'll be plain tap water, may I add the citric acid just to 'spice' the water up?

Flushing at 6-month intervals. The answer to your 2nd and 3rd questions -- yes! The pH of your tap water for flushing should be 6.5, so acidify accordingly -- don't bring the pH down any lower than 6.4. Fill one of your 50-liter buckets with water, add the citric acid in 1/2 teaspoon increments one increment at a time, and test the pH of the tap water with each increment. When you get close to the pH you're looking for (let's say you're at 6.6), fine-tune the pH with 1/4 teaspoon increments. What you'll do is "sneak up" on your target pH -- this takes some patience. If you keep track of how many increments it took to get there, write down the total amount you need for dilution and remember it. Then when you acidify again, you won't have to keep going through that tedious exercise.

From Fish Lab (https://fishlab.com/aquarium-kh/):

• "Beginners often confuse carbonate hardness (KH) with general hardness (GH). While both have the word hardness in their name, they measure different parameters of your water.
  
  "Carbonate hardness (KH): The measure of carbonates and bicarbonates dissolved in water.
  
  "General hardness (GH): The measure of magnesium and calcium dissolved in water.
  
  "If you have ever heard someone say…
  
  "I have really hard water where I live.
  
  "They are talking about GH.
  
  "In nature, GH and KH go hand in hand. If a waterway has a high GH, it will also have a high KH.
  
  "But tap water is usually anything but natural…
  
  "It’s actually possible for your tap water to have a really high GH and a very low KH. So, just having a high GH does not automatically mean that you also have a high KH."

That in itself is confusing because it doesn't make the distinction between carbonate (KH) and bicarbonate (KH plus alkalinity) -- alkalinity is the only thing you can test with a pH meter. "So, just having a high GH does not automatically mean that you also have a high KH." Yeah, but it doesn't automatically mean that you have a low carbonate KH either -- the primary reason for flushing your pots with acidified water every 6 months is to deal with the possibility of excessive carbonate buildup in the mix. If you also have excessive fertilizer salts building up in your pots, that's the secondary reason for flushing. Call it as a sort of an "insurance policy" preventing long-term problems that may be caused by either or both types of nutrient-blocking buildup in the mix.

[Wiandry Adi]

Hi Steve,

After painstakingly waiting for days, my granular gypsum have arrived! I'm planning to use them as soon as possible, see if my collections like it.

While you're at it, I came across a realization about my ferts' water solubility. I was trying to find alternative fert formula from ferts that have better water solubility than Mutiara GROWER and Pak Tani, and those that are coming in crystalline powder form for better, more uniform weighing results (as well as better stirring experience; stirring granular ferts until they're dissolved is quite a pain in the gluteus maximus).

Granular ferts seems to leave a bit of residue when left for a while, esp. overnight, and I was thinking about using a spraying system in the future (like the one you carry on your back and spray your plants care-free while the spray pumps the water for you) and I was concerned that my ferts' residue may potentially clog the sprays and become a relatively expensive mess.

I'd like to try this next month or next year if you insist to keep using the current fert formula. I have found the candidates (all ferts listed are in crystalline powder form):

• PROVIT Hijau 27 - 8 - 19 + 1MgO + TE (https://meroketetapjaya.com/files/uploa ... HIJAU1.pdf)

• PROVIT FLEX-G 8 - 9 - 39 + 3MgO + TE (https://meroketetapjaya.com/files/uploa ... FLEX-G.pdf)

• the default SOP (potassium sulfate) and ZA (ammonium sulfate)

I'll crunch the numbers and give the results next month when I can purchase both PROVIT Hijau and FLEX-G. Though, I'll stick to the current formula for a while since I'm starting to see nice progress in my collections thanks to said formula.

[Steve Johnson]

Hi Adi,

I know what you mean about the granular fertilizers -- you might grind them up with a mortar and pestle, but that's way too labor-intensive. You're on the right track with crystalline powders, so I'd say that PROVIT Hijau and PROVIT FLEX-G show some promise. However, I'll need to investigate them further. Here's my initial assessment:

• If you put both PROVIT ferts together in equal measure, the P side of the ratio will be 0.34 and the K side of the ratio will be 1.14.

The ammonium sulfate is there to bring the P down with the ferts you're currently using, but you won't need it if you go with the Hijau and FLEX-G. Although K will be within the optimal 1.1-1.7 range, supplementing them with potassium sulfate can bring the K up to the higher end of the range. I'll crunch some numbers myself and see if we can figure out the right amounts of Hijau, FLEX-G, and potassium sulfate for dilution per 50 liters of water. (Mmmmm, crunchy numbers taste good! ) I really like the fact that both ferts contain good amounts of micronutrients, so this may be superior to what you're getting from the PROVIT Orange.

The fact that you're already seeing some improvement tells us that your plants are responding well to the fert regimen I recommended, and nice that you''re seeing it happen so quickly. If the PROVIT Hijau and FLEX-G combination works as I hope it will, things will get even better over time. I'll get back to you as soon as I run a few calculations and see if we have the right combo.

[Wiandry Adi]

The ammonium sulfate and potassium sulfate are there to bring the P down with the ferts you're currently using, but you won't need them if you go with the Hijau and FLEX-G. In fact, you'll need to bring the P up to get the optimal range of 0.25-0.35. I'll crunch some numbers myself and see if we can figure out the right amounts of Hijau and FLEX-G for the P in that optimal range. (Mmmmm, crunchy numbers taste good! ) I really like the fact that both ferts contain good amounts of micronutrients, so this may be superior to what you're getting from the PROVIT Orange.

The fact that you're already seeing some improvement tells us that your plants are responding well to the fert regimen I recommended, and nice that you''re seeing it happen so quickly. If the PROVIT Hijau and FLEX-G combination works as I hope it will, things will get even better over time. I'll get back to you as soon as I run a few calculations and see if we have the right combo.

Good to know!

Since you've greenlighted the PROVIT Hijau and FLEX-G, I'll get them this week and I'll weigh them just like our previous project, only this time I'll skip the one-teaspoon measurement. Or, are there any other measurements/results you'd like to have?

Though, I have calculated a really rough dosage for each ferts, as the missing data are each ferts' weigh per 1/2 teaspoon, the ppm numbers, and pH results. Here are the numbers so far:

PROVIT Hijau : 2 x 1/2 tsp
PROVIT FLEX-G : 4 x 1/2 tsp

Meroke SOP : 1 x 1/4 tsp (potassium sulfate)
Meroke ZA : 1 x 1/4 tsp (ammonium sulfate)

Why the PROVIT got 6 x 1/2 tsp? I counted on the current formula, it got 6 x 1/2 tsp as well ( 3 x Mutiara GROWER, 2 x Pak Tani, 1 x Provit ORANGE). This is me rounding up the numbers for Hijau and FLEX-G, so you may have better calculation/recommendation.

[Steve Johnson]

I had to correct a boo-boo from my previous post -- PROVIT Hijau is 27-18-9, not 27-8-9. Equal measures of PROVIT Hijau and FLEX-G give you 0.34 on the P side of the ratio (excellent), and 1.14 on the K side of the ratio. You won't need ammonium sulfate, just potassium sulfate so you can bring the K up to the higher end of the 1.1-1.7 range. What I mean by "equal measures" is 1 teaspoon Hijau to 1 teaspoon FLEX-G. I'll have to do some calculations for the right amounts of each fert plus potassium sulfate, and I can do that for you over the weekend if not before. In the meantime, please see this while we're thinking of it...

1 metric tsp. (5 cc) -- potassium sulfate = 13.3 grams

This'll be a good way to find out how accurate your metric teaspoon measurement is. Put 1 level teaspoon of potassium sulfate on your scale and write down the weight, then let me know the number. If there's a deviation, I can factor it into the calculations I run for the PROVIT Hijau and FLEX-G ferts.

[jerrytheplater]

In that case, I do know two ammonium sulfate and potassium sulfate ferts that I can get (and I see they're in water-soluble crystalline powder form). Shall I get those and measure their weights?

Actually no, we have a handy-dandy calculator for that:

https://www.aqua-calc.com/calculate/vol ... nk-sulfate

https://www.aqua-calc.com/calculate/vol ... nk-sulfate

1 metric tsp. (5 cc) -- ammonium sulfate = 8.85 grams (1.88 grams N, 2.12 grams S), potassium sulfate = 13.3 grams (5.97 grams K, 2.45 grams S).

Steve, those calculators are using the density of the solid chemical. The fertilizers we buy are granular. You can't use that conversion.

I've told you this going way back a few years now. You are getting forgetful!! I'm too lazy to go back and search, and it might have been in a PM. Adi does need to weigh his fertilizers and take an average of about 10 measures. Try to be careful that the spoon doesn't get packed down and on and on.

This is why weight trumps volume for granular substances. Way to many variables.

[Wiandry Adi]

I had to correct a boo-boo from my previous post -- PROVIT Hijau is 27-18-9, not 27-8-9. Equal measures of PROVIT Hijau and FLEX-G give you 0.34 on the P side of the ratio (excellent), and 1.14 on the K side of the ratio. You won't need ammonium sulfate, just potassium sulfate so you can bring the K up to the higher end of the 1.1-1.7 range. What I mean by "equal measures" is 1 teaspoon Hijau to 1 teaspoon FLEX-G. I'll have to do some calculations for the right amounts of each fert plus potassium sulfate, and I can do that for you over the weekend if not before. In the meantime, please see this while we're thinking of it...

1 metric tsp. (5 cc) -- potassium sulfate = 13.3 grams

This'll be a good way to find out how accurate your metric teaspoon measurement is. Put 1 level teaspoon of potassium sulfate on your scale and write down the weight, then let me know the number. If there's a deviation, I can factor it into the calculations I run for the PROVIT Hijau and FLEX-G ferts.

Copy that.

So what I'll do next is:

• Get the Hijau and FLEX-G

• Measure them all by 2 x 1/2 tsp (for additional data besides potassium sulfate's weight)

• Change the Hijau+FLEX-G's dosage proposal into 1 tsp each fert - including removing the ammonium sulfate

Also, by '1 teaspoon', do you mean that I still use two 1/2 tsp or the good ol' 1 tsp? Regarding the inaccuracies known from previous experiment, I may still incline to two 1/2 tsp.

[Wiandry Adi]

In that case, I do know two ammonium sulfate and potassium sulfate ferts that I can get (and I see they're in water-soluble crystalline powder form). Shall I get those and measure their weights?

Actually no, we have a handy-dandy calculator for that:

https://www.aqua-calc.com/calculate/vol ... nk-sulfate

https://www.aqua-calc.com/calculate/vol ... nk-sulfate

1 metric tsp. (5 cc) -- ammonium sulfate = 8.85 grams (1.88 grams N, 2.12 grams S), potassium sulfate = 13.3 grams (5.97 grams K, 2.45 grams S).

Steve, those calculators are using the density of the solid chemical. The fertilizers we buy are granular. You can't use that conversion.

I've told you this going way back a few years now. You are getting forgetful!! I'm too lazy to go back and search, and it might have been in a PM. Adi does need to weigh his fertilizers and take an average of about 10 measures. Try to be careful that the spoon doesn't get packed down and on and on.

This is why weight trumps volume for granular substances. Way to many variables.

Oh, did I miss something? I was about to propose an alternative formula from different fertilizers - now all of them are in crystalline powder form, and are there any errors in the calculations for my current formula? Also, by 'take an average of about 10 measures', what does that mean, and what should I do?

If there are indeed any errors, I'd cut the ferts' formula by a quarter (in that each application, the granular ferts does not fill the teaspoon all the way up, just enough room for the empty space to fill in the rest).

[jerrytheplater]

The calculator Steve posted uses the density of the solid chemical fertilizer. The number used is correct, but the technique is not. You can't use this calculator to calculate the weight of granular chemicals. Round pellets have air space between them. When you fill any teaspoon there will always be spaces between the particles. That teaspoon is not full of the chemical, so it won't really be one full teaspoon of the chemical. If you melted the fertilizer and poured it into the teaspoon, then you could use Steve's calculator. It will be full then.

If you insist on using teaspoon type measures instead of weights, you need to know how much each fertilizer weighs in each measuring spoon you use.

Try taking 10 measurements. Measure out fertilizer in your spoon. Weigh it. Write it down. Repeat 9 more times trying to fill the spoon the same way each time. Take the average of your 10 measurements and use that number for the weight of your fertilizer.

If you get a new bag of fertilizer, a new brand of the same stuff, you will have to weigh it out all over again. It may have been made differently and the particle sizes may be different.

Here is an example I did back on April 17, 2008. I was weighing a Trace Element product called CSM plus B very commonly used in the aquarium hobby to fertilize aquatic plants. This product is a very fine powder, not coarse granules. It is dust like.

I weighed 5 Tbs CSM-B into a tared plastic container six times, leveled off the measuring spoon with a metal straight edge. Dumped the CSM-B back into the bag after each weighing. The 7th time I tapped the Tbs. a few times before leveling to remove the air and settle the material in the Tbs. Notice the significant effect on the weight.

Wt. in grams of 5 Tbs. CSM+B = 98.96, 98.31, 97.88, 98.66, 98.03, 97.97, 101.04. The average of the first 6 weighings comes out to 19.66 grams CSM+B per US Tablespoon. The seventh number shows what happens when you tap the spoon a few times to settle the particles in the spoon. (I did it after each of the five times I filled the Tablespoon for the last weighing) The particles pack more closely and you can get more in.

That same tablespoon held 15.84 grams of water, so it has a volume of 15.84 ml when it is usually considered to be 15 ml.

[MikeInOz]

If you insist on using teaspoon type measures instead of weights, you need to know how much each fertilizer weighs in each measuring spoon you use.

Actually Jerry, you really don't. Just use a gram (or 5 gram or whatever) measuring spoon for all fertilizers and you're done.
Eg., I use a prilled version of calcium nitrate all the time for my orchids. The round prills are coated with a wax to stop them absorbing atmospheric water. They are about 3mm in diameter. When I want a gram of CaNO3, I scoop them up to level in my 1 gram spoon, and bingo, I have a gram of calcium nitrate. If want half a gram, then I fill it half way. It won't make the slightest observable difference in the plants.
We are not doing lab experiments and writing scientific papers. I have never weighed a fertilizer in my life because I have never need to.