Amonium Sulfate

[newnandawg]

For those of you that use Amonium Sulfate for your blueberries, how much and how
often to use?

[WillsC]

Mike,

Not for you because I bet you already know but think it is wise to tell people there are different forms of AS and the one they want is the white crystalline water soluble type.

For pots 1/2 tsp dissolved in a gallon of water per week? Don't have to use the entire gallon on one plant lol. If the plants are in ground you can double that. Also note that if the plants are dry and you use the AS you will burn them to a crisp so AS ONLY on plants that are moist to start with. If the plants do get a bit dry water them with just water and the next day use the AS.

[Gina]

That's about what I give mine too. Maybe a bit more at times, and sometimes more often since I often water more than once/wk.

I water with a pond pump with hose attached, and treat the water to how I want it in trash cans first. That is when I add either the AS, sometimes with a bit of MiracleGro, sometimes chelated iron, sometimes sulfuric acid to adjust pH if using tap water. When I was using tap water, I'd fill the trashcans the day before so the chlorine could off-gas.

[newnandawg]

Thanks to Gina and Wills. I do know which AS and have been using it. Just wasn't sure about how often others were using it.

[m5allen]

Like others have said, use frequent, small doses. This stuff is like liquid crack for blueberries.

[WillsC]

I had a couple messages privately about AS and think a clarification is needed. AS is simply nitrogen, 21-0-0 but comes from sulfur so helps to acidify the soil. There is nothing else in AS, no weird stuff nothing that can hurt you or the plant (as long as you use it in the right dose and the plants soil is moist), it is just nitrogen. The reason why as Mike said it is like crack is AS has a beneficial and unique way of clinging to soil in pots so it stays there available to the plants. Many other forms of nitrogen wash easily out of pots with the next watering or rain so less is available for the plants.

There is no need at all for balanced fertilizers, is a bit of a myth. Plants need nitrogen ALL the time. They only need the other components of fertilizer now and then. Think of it this way and this is really simplified but think of the food you eat every day as nitrogen.....you need that constantly, daily to stay healthy. The rest of the components of fertilizer think of as Vitamin C. You do not need vitamin C every day to be 100% healthy, just now and then and without it you will eventually get sick with scurvy. With BB I feed them just nitrogen.....once every other month they get a balanced fertilizer with micros but I grow in ground so many of the elements are already in the ground. In pots AS weekly is great and balanced once a month. The other components of fertilizer tend to stay in the soil anyway unlike nitrogen.

If you have eaten at Subway you have eaten AS, it is in the bread

[drew51]

I like to supplement with regular acid fertilizer with trace elements because I don't grow in soil, compost has a lot of nitrates, so I don't add that either. I grow in pine bark and peat moss, not soil, so I want to confirm everything is there. Two years ago with my peaches I had a manganese deficiency as the local soil lacks it completely. Once added the trees looked great! It's hard to give a universal formula for anything. All gardening is local. I also use AS as the product works so well. Just be careful I have probably burned blueberries with it using it when soil was dry.

[newnandawg]

Thanks to Wills and Andrew for those explanations.

[WillsC]

Andrew,

Definitely do not want a deficiency but like I said most components of fertilizer stay in soil quite well and do not wash through........Nitrogen though does leave soil especially potted soil fast so even in pots once a month addition of balanced fertilizer with micros is often enough and my bet is you could go 3 months between using the balanced in pots and still be just fine. The nice thing about plants is if they are short of something they do tend to let you know

[drew51]

Andrew,

The nice thing about plants is if they are short of something they do tend to let you know

Yes, it looked like they used my leaves for the photo online of Manganese deficiency. Applying to the ground, and foliar spray worked.
I would like to find ways to cheapen fertilizer costs. Composting is one, using grains like Cottonseed and Alfalfa is another. I only apply a balanced fertilizer about twice a year. I might apply more, but man the stuff is expensive!

[Kelby]

I use a lawn fertilizer (Scott's) that is primarily AS. Per directions from some university I apply at 4 TBSP/plant around the drip line, increasing to 8 TBSP after 5 years. Can reapply at 6 week intervals if more growth is desired (6-12" being good). In years when organic mulch is applied, increase by 50%. I also throw on some soil acidifier (Espoma) and Hollytone.

[WillsC]

Andrew,

Buy where the farmers do. Here say at lowes you are talking a buck a pound? Where I buy my fertilizer where the citrus and blueberry farmers buy theirs a 50 pound bag of 10-10-10 $14 very high quality and has all the micros. AS $12 for a 51 pound bag, I have no clue why it is 51 pounds. If you have a Helena chemical in your area try them, it is a national company so they have outlets across the country.

[drew51]

Will do, thanks for the tip!

[The_Gardener]

I paid $11.50 for 5 pounds on ebay.

[WillsC]

ouch.

[Sarahkt]

OSH has 20-lb bags of AS (Lilly Miller brand) for $14.99. Still not as cheap as you could get, but better than eBay prices.

[Sarahkt]

Yes, I used it yesterday on the blueberries at ~1/2 tsp per gallon and it dissolved quickly with a little stirring. I just made up a couple buckets to the 10 L fill line, added half a Tbsp to each and stirred it in. I then pH'ed the water with sulfuric acid and pH strips. Two buckets was enough to water all my blueberries and a gardenia.

The crystals were snow white and not brownish/beige, if that matters (not sure if it does, unless it's a sign of trace impurities from manufacturing).

[bahamadan]

If I may ask where do you get your pH strips from? I bought some well reviewed ones on Amazon, and they work on the pH 4, 7 and 10 calibration solutions I bought to make sure they work, but they don't work on my water with nor without fertilizer or acid added, so I'm thinking maybe I have the wrong kind.

[Sarahkt]

pH strips work better in well-buffered solutions like your stock solutions. Unbuffered solutions (like blueberry water) have higher chances of giving you a false reading. I doubt my pH strips (from lab, or from Amazon) are perfectly accurate on water. They're intended for blood, urine, saliva, buffers, etc.

I use them anyway knowing this. I could get a much better pH meter instrument but using pH strips to pH my water hasn't killed my blueberries yet and I'm trying to streamline the process of fertigating them properly without getting even more gardening apparatuses. They're actually doing surprisingly well in their pots.

[WillsC]

Just make sure it is the water soluble kind. 20# will last the average person a LONG time. Even with 300 BB bushes and using some AS on other plants I still only use about 1 51# bag a year. I just got back from picking up 1000 pounds of blueberry special. It has went up, $15 per 50#

[Sarahkt]

It's being delivered today, so we shall see. It looks crystalline in the pictures.

Yep, 20 lbs should last my ~20 plants a good long time. Good thing it doesn't really expire.

[WillsC]

No it will last forever but it is very hygroscopic so have to keep it sealed tight or turns as hard as cement.

[Sarahkt]

Yep, it's crystalline. The good stuff.

Thanks for the tip on its being hygroscopic, it's in a plastic bag now but I'll move it to an airtight container.

[julia.scheidt]

I'm using AS but it doesn't look as crytalline as you say. It's dirty crystals. Kind of brown. But it is soluble in water anyway. Is this one good to use??

[Gina]

I've gotten the dirty looking stuff too. It works, but is not nearly as appealing as the snow-white stuff.

[bahamadan]

My experience has been the same as Gina's with the brown crystals, they work although for me they take a little while to dissolve in cold water with some stirring. It's the only kind locally/nationally available, so I usually warm up a small quantity of water and dissolve the total amount of crystals in that, then pour that solution into the bigger container of cooler water once the crystals are dissolved.