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Fruit & Orchards

How much fertilizer for blueberries?

9 years ago

Hi,

I have bought 1 bag of Ammonium Sulfate, 1 bag of MKP (monopotassium phosphate), and 1 bag of micronutrients (iron, etc).
The fertilizers are all in grainy form like little crystals.
I would like to know how much fertilizer and water I should use to fertigate blueberries.
I have burned my blueberries before and I wouldn't like to burn them again.
Thanks.

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Comments (6)

BahamaDan Zone 12b Subtropics
9 years ago
Hello Julia!

Great of you to grow blueberries; I've started with them myself. I'm not familiar with MKP and not sure what the directions of your micronutrient bag advise, but as for the Ammonium Sulfate: There is a grower on here named Fruitnut who has been extremely successful with growing blueberries (in containers) and he uses a rate of 1 tablespoon per 2.5 gal of water once a week. He also added Osmocote slow-release. I'll link one of his blueberry posts for you to read through. Some great info there as well as fertilizer recommendations.

Happy Growing!

Dan

Here is a link that might be useful: One and 7 yr blueberry growth with pictures
User
Original Author
9 years ago
@BahamaDan,
I guess my mistake was to apply 1 tablespoon per 2.5 gal of water almost EVERY DAY! I didn't know that it should be applied only once a week. Thanks for the information, now I can do it the right way! =)
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If you are wanting to use the shotgun approach, here's what I would suggest: Use either Miracle Grow's all purpose continuous release plant food (shake 'n feed with the yellow cap) or Gertens acid loving plant fert. Apply one or the other early in the season after leaves are out. Both are controlled release and will fertilizer for an extended time. Were it me, I'd apply at 1/2 of the rate suggested on the label. BB's don't require a lot of fert (adapted to low fertility soils), and there is a good chance your soil has plenty of P & K already. Then, on a weekly or bi-weekly basis, starting a few weeks later, disolve 1/8th or less of a teaspoon of Ammonium Sulfate per gallon of water, and water the root zone of the plant. That is about 1/2 the concentration rate I typically apply (I use just under 1/4 tsp per gallon), but that is to compensate for the nitrogen already in the controlled release ferts. Cut off the Ammonium Sulfate by the middle or end of July, earlier if you get frost in August. The application of Ammonium Sulfate will push rapid growth, and apply sulfur to continue to keep the pH down. However, if your pH gets too low, you should stop the Ammonium Sulfate application, or switch to urea as your nitrogen source. Avoid nitrogen sources that are nitrate based. I didn't suggest Osmocote as a controlled release fert as approximately 1/2 of the nitrogen is nitrate based, rather than ammonical. People have used it without apparent deleterious effects, but there are better alternatives out there with less nitrates. Water well periodically to ensure salts from a potential over-application of ferts have a chance to be flushed past the root zone. This post was edited by charina on Fri, May 30, 14 at 16:38
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BahamaDan Zone 12b Subtropics
9 years ago
No problem Julia, happens to the best of us. I've killed my share of plants when I was starting out as well; the important thing is you're willing to learn how to better cultivate plants and it is that attitude and willing disposition that will lead you to success with your plants!

A good method when container gardening is also to flush your soil with straight (unfertigated) water every 3rd or 4th watering, so as to prevent salt buildup. Not sure if your blueberries are in containers; if not disregard :)
User
Original Author
9 years ago
@BahamaDan Yes, they are in containers!
Last year I bought them and started fertigating every day with ammonium sulfate and water. They grew very fast and strong. They were all beautiful!!! But then suddenly, one day, they began to burn.... That's when they stopped growing at all... It was as if they had got into dormancy, except it was not winter.... I had to wait many months for them to recover... Now they finally started to grow back again. Don't wanna repeat the same mistake.

One thing I noticed is that the Jewel variety is less prone to burning than the Snowchasers. My Snowchaser blueberries got all burned from the fertilizer, while the Jewels remained mostly green and healthy, with only a few leaves burned.
BahamaDan Zone 12b Subtropics
8 years ago
How are they doing now Julia? ;-]
BahamaDan Zone 12b Subtropics
8 years ago
last modified: 8 years ago
Here's a picture of my Sunshine Blue, I really should fertilize it more though as I honestly can't remember the last time I gave it liquid feed lol. Hopefully I put some granular acidic feed on the soil surface a month or two ago...

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