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Calculating mixing rate of ammonium sulfate for blueberries

Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
Fri, Jul 5, 13 at 20:27

Mrclint was kind enough to post the link below concerning blueberry fertilization with ammonium sulfate, AS, 21-0-0.

If I'm reading correctly it says that at rates higher than 1.0 g/liter AS becomes a salt problem when growing blueberries. So I'm cutting that in half to provide a safety margin. That equals rounded off ~2 grams per gallon. AS weights 4.6 g per teaspoon. The rate I've quoted before was about one teaspoon per 2.5 gallon jug. That still seems about right and about 0.5 g/liter.

More accurate calculations says 2.5 gal equals 9.45 liter. So 1.0 teaspoon AS (4.6g) diluted in 2.5 gal equals 0.49 g/liter.

I know that's not real easy to follow but that's my calculation.

So I think 1 teaspoon AS per 2.5 gal water is a safe rate on blueberries in pots if there is a decent leaching fraction. It's been working for me and this literature says it's safe if properly used.

Here is a link that might be useful: Ammonium sulfate on blueberries


Follow-Up Postings:

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RE: Calculating mixing rate of ammonium sulfate for blueberries

Hmm......that is a bit lighter than I use. I have been using 4 cups to 300 gallons of acid treated water. I guess with our rains salt build up probably is not an issue.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Fri, Jul 5, 13 at 23:08

Remember I cut the upper limit rate in half. And yes on your sand with your rain even the upper limit rate would probably be fine.

In pots it's harder to get even leaching so I built in a safety factor.

In 300 gallons I think as much as 1.2 liters, that's about 5 cups would be safe. But don't take that as an indication to increase your rate.

This post was edited by fruitnut on Fri, Jul 5, 13 at 23:27


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RE: Calculating mixing rate of ammonium sulfate for blueberries

fruitnut,
All this time,I thought your recommended dose was one tablespoon per two to three gallons of water.I'll need to correct that. Thanks,Brady


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Yeah i was using one Half teaspoon per gallon of water on my potted blueberries. Have seen phenomenal growth using this mixture with no damage or buildup vs my first fertilization attempt at the beginning of the season. New to blueberries, but this method is working on my 6 potted plants. Picked some Polaris and Patriots this morning. Very Tasty.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

"fruitnut,
All this time,I thought your recommended dose was one tablespoon per two to three gallons of water.I'll need to correct that."

I had thought and read the same as well. Although the granules don't all break down with the water when I add to a jug so they are obviously getting less than what I was giving them.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

  • Posted by mrclint z10SoCal Valley (My Page) on
    Sat, Jul 6, 13 at 12:50

Posted to the wrong thread. Nothing to see here. :)

This post was edited by mrclint on Sat, Jul 6, 13 at 12:52


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Melikeeatplants.

There are two versions of the AS.one is water soluble instantly and the other version takes some agitation to dissolve.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Yeah, I put it in the can and spray with hose and shake it, that dissolves some but not all. I guess you guys are using the water soluble type. I'll have to look out for it...


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Do you have to worry about any leaf burn if some of the AS solution remains of the leaves of the plants?


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Northern,

I would imagine it would burn if the concentration was too high but at the rate Fruitnut advised? I think it would be ok. Might be something you would want to test on a single bush.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Just to clarify....would you BB fertilizers indicate if these rates are for every watering or an infrequent watering? 1/2 teas/gal is approx 125 ppm of N, I believe. Always good to talk about ppm of N.

Thanks


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RE: Calculating mixing rate of ammonium sulfate for blueberries

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Sun, Jul 7, 13 at 23:15

marc:

The researchers were watering potted blueberries 2-3 times per week with a range of rates up to 3 times the rate I settled on. The highest rate caused damage. You might study the report I could be wrong.

I've mostly fertilized once a week but might go 2-3 times per week if wanting really fast growth. But I'd use pure water between fertilizer applications. You could probably get by using only the fertilizer solution but if doing that I'd run a large leaching fraction or cut the concentration more.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Hi Fruitnut,

So for I have applied 3 table spoons of Espoma Plant tone 5-3-3 organic fertilizer twice to my Blueberry plants in 10G containers in monthly intervals. After going thru this thread and few other threads, i'm thinking of using Ammonium Sulfate.

I used to water blueberry plants using rain water but now I acidify the tap water using battery acid to pH 5 and water the the plants.

Please help me with the below questions.

1. Can I add the Ammonium Sulfate directly to the acid water and fertilize blueberries when watering?
2. What is the ideal frequency for fertilizing potted blueberries with Ammonium Sulfate
3. You had mentioned that you would use pure water in between fertilization, does pure water equals tap/city water?

Appreciate your help.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Mon, Jul 8, 13 at 13:49

1. Ammonium sulfate is safer dissolved in water before application. Applying granular and watering in is more likely to lead to salt burn IME. Also contributing to burn potted plants is applying fertilizer and not watering enough for periodic leaching.

2. It depends on how fast you want the plants to grow. I'm only in a big hurry on new plants that haven't fruited. There I might fertilizer 2-3 times per week. But even once per week can push pretty fast growth. After a plant reaches the size I want then it's once a week to once a month.

3. Pure water to me is rain water. Or if out of that tap water acidified to pH 4-5. Rain water is better if at all possible.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Thanks for the info here. BTW nandakumar mentioned Plant Tone. Which i think is an excellent organic fertilizer. It contains sulfur, and beneficial microbes also. Once plants reach maturity, it may be a better choice to use. And for those who wish to remain organic, it is the product to use.
I myself will be following my own advice once my plants are established. Once in a while I have to use tap water when out of rain water, so the continued use of sulfur is needed and this is a great way to do it all, Sulfur, microbes, and fertilizer all in one. It may have the trace minerals too, have to check.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Drew,

Just understand that the sulfur in the fertilizer won't balance the bicarbonates in the water if the water is even fairly hard.

Just to add one thing to the excellent advice Fruitnut gave. Make sure you you don't apply the AS to dry plants. Best is to water them one day with normal water and fertilize the next day if you are even slightly concerned the soil is too dry.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

"Drew,
Just understand that the sulfur in the fertilizer won't balance the bicarbonates in the water if the water is even fairly hard.
"

Well only occasionally do I use city water. I only have 3 BB plants, and keep 100 gallons of rainwater. When it is 1/2 depleted, the last 50 gallons go for blueberries only. But once in a while I use the hose to really soak them. Like before I leave for a long weekend. Plus I do have sulfur on hand too! I prepared raised beds a year in advance with ton's of sulfur. And also added more twice this spring.
Currently I'm only using an organic for blueberries, and AS.
A couple years down the road, I'll probably use Plant-Tone.
My city water is 7.8 pretty high! Yikes! Again only used 3 or 4 times a year. Yeah the PH of the beds was around 4.5 -5.0 this spring, I would have to add a lot of city water to raise them above 6.0, I'm not concerned at this point.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Thanks fruitnut and all,

I got all of my 7 blueberries this winter and transplanted them to larger containers but still couple of them are yet to have any new growth/shoots. I think I may have to apply Ammonium sulfate probably twice a week to have nice growth and to expect decent fruits next year.

I think I missed to ask about the duration before, could you please let me know for how long I need to apply the AS, until fall end or even up to the next winter.

Thanks


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RE: Calculating mixing rate of ammonium sulfate for blueberries

  • Posted by fruitnut z7b-8a,4500ft SW TX (My Page) on
    Mon, Jul 8, 13 at 16:39

nandakumar:

It takes about a month of frequent fertilization before the strong growth kicks in. Then you need to allow the plants time to harden up before cold sets in. So you've got a couple months of rapid growth if starting now. Don't push them hard once a real freeze is possible.


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Drew, I would be real carefull with that sulfer. Its easy to over use and using the words "Tons of sulfer" give me chills. Ive had some bad experiences with sulfer. Alittle goes along way!


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RE: Calculating mixing rate of ammonium sulfate for blueberries

interesting discussion.

Would like to know whether applying ammonium sulfate can be considered as Organic?


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Ammonium sulfate is not organic. Here's a video that shows a couple of small batches of ammonium sulfate in liquid form being mixed up. I'm not sure why he's cooking the powder at the end. Looks like a highlight from a "Breaking Bad" episode doesn't it? Non-organic growers take the crystalline form of either mix method, dilute with water and fertilize plants (including food plants) with it. Subway uses ammonium sulfate in their bread dough.

This post was edited by mrclint on Tue, Jul 9, 13 at 3:18


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RE: Calculating mixing rate of ammonium sulfate for blueberries

Follow-up on this thread,

it has been three weeks since I started applying AS to my blueberries and all of my plants now has new growth/sprouts. First freeze in Dallas usually occurs in the first week of Nov, considering this freeze timeline, please let me know when to stop applying AS to my blueberries.

Thanks


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