What're the NPK %s of the fertilizers you're using - are they soluble synthetics?

Al

HI Al,

For the blueberries I am using this;

{{gwi:24022}}

and for the lemon this;

{{gwi:24023}}

Since both your fertilizers have Mg, it's unlikely you need to supplement with Epsom salts - especially since high Mg availability limits Ca uptake. You should be avoiding nitrate forms of N for your blueberries. Switch to the MG (also an acid-forming fertilizer) and they will straighten out.

I think your citrus might be needing more Ca - especially because of the Epsom salts you're applying. Stop the Epsom salts and add maybe 1/2 tsp/container of gypsum to the top of the soil. If you want to experiment, dissolve some CaOH in water, then leave it set overnight. Scoop off a little of the supernatant and mix it 4:1 with water - use it to spritz a few leaves (keep track of which ones you spray). If they green up, you know it was a Ca deficiency.

Al

Thanks Al, ill add some gypsum to the lemon, although only the blueberries were receiving Epson salts.

And just to confirm, you recommend dropping the acid fertiliser I'm currently using for the blueberries and swapping to the miracle grow for the blueberries which use a urea based nitrogen source?

Yes - fertilizers in nitrate form are often toxic to blueberries. I suspect that's what you're seeing in them. Choose urea or ammonium based fertilizers, but not ammonium nitrate.

Al

Ok I'll switch back, I was originally using the miraclegrow for the blueberries as well, but in another thread someone suggested swapping to an acid-loving fertiliser mix, which is what the first photo supposedly is. Having a look at the nitrogen sources on the label 2/3 of the N in the acid mix comes from ammonia sources, and 1/3 from nitrate.

I have another question about urea, I understand that it only transforms into ammonia in the presence of soil bacteria. Are such bacteria likely to be present in the 5-1-1 mix?

I don't know the answer to your question, naikii, but I can say that I have good results with a fertilizer whose nitrogen is largely urea (Miracid - 27% urea/3% ammoniacal nitrogen). With regard to blueberries and nitrates, I've included a link to a thread in the Fruit forum that might interest you.

Here is a link that might be useful: Osmocote for blueberries?

Oops. It just dawned on me that I'm the one who steered you in the wrong direction with regard to your fertilizer of choice, and I apologize for that. I use MirAcid rather than the original Miracle Gro and assumed (wrongly) that that the latter includes nitrates (which it obviously doesn't). I was trying to steer you away from nitrates, and I all I did was steer you to a product with nitrates. That being said, other blueberry growers have reported good results with fertilizers that do include some nitrates (as you'll notice in the linked thread). I wonder if rabbiteyes are more sensitive? That might explain why your highbush cultivars aren't suffering the same chlorosis symptoms, which is both odd and interesting.

This post was edited by shazaam on Sun, Apr 7, 13 at 21:07

I too thought it was intesting about the rabbiteyes. I also have some southern highbush types; legacy, misty and sunshine blue, which dont really show the same problem either.

Of the southern highbush, misty has done almost nothing since I planted it 2 months ago, and the stem is going red, as is one or two of its leaves, I think it is preparing for winter, and overall hasnt done very well- but isnt showing any chloriosis.

{{gwi:24024}}

Legacy is planted in the ground, and in a slightly higher pH, I am guessing around 6. It is showing similar deficiencies to the rabbiteye, though not so pronounced, you can see in this photo taken about two weeks ago some leaves have slightly lighter colour with darker veins. This was planted into the ground about 3 months back;

{{gwi:24025}}

Sunshine blue doesnt seem to have the same discolouration, although is growing new leaves with a slightly reddish tinge, which I believe could be N related, or just how the plant grows

{{gwi:24026}}

However all the highbush types I have; Denise, Blue Rose, Brigitta and Blue Crop all have bushy bright leaves (although the latter two were only planted 2 weeks ago).

Finally there is one other difference. All the plants with chloriosis (and the under-performing Misty) were purchased online from one location, the highbush from the same local nursery, and the sunshine blues and legacy from a big hardware store.

So perhaps it is something inherently different with the plants purchased online (from a very popular, and well reveiewed online nursery in Aus)

here is an articul i read before that helped me understand why ammonium based fert is better for blueberry plants.

Nitrate fertilizers (NO3- ): Nitrogen present in these fertilizers are in nitrate form, NO3 - which are rapidly dissociated to release NO3-ions and readily absorbed by the plants. Nitrate ions highly reactive and mobile are susceptible to losses due to leaching and under water-logged conditions by denitrification. They are ALKALINE in their residual effect in soil.

Ammonium fertilizers (NH4+): Ammonium fertilizers are soluble in water and, as such, absorbed on the soil colloids and thus protected from being washed away by run off or by leaching. Some crops like rice, sugarcane, tuber crop, seedlings directly utilise ammonium form of these fertilizers. The absorbed ammonium ions on soil collections are transformed to nitrate slowly and taken up by most of the crops. They are ACIDIC in their residual effect in soil.

as you see the reason(from what i understand is )ammonium is acidic which good for blueberries and nitrates leaves an alkaline residue.

shazaam.... other blueberry growers have reported good results with fertilizers that do include some nitrate

Nitrate and Ammonium fertilizers (Nitrate, NO3- and ammonium, NH4+ ): These fertilizers contain nitrogen in both nitrate (NO3- ) and ammonium forms (NH4+ ). The nitrate nitrogen is readily available to plants for immediate need, whereas ammonium nitrogen becomes available to plants at a later stage, when it is transformed by microbiological process to nitrate. They are soluble in water and suitable for most of the crops and soils. They are ACIDIC in its residual effect. some examples are Ammonium nitrate,Calcium Ammonium Nitrate and Ammonium Sulphate Nitrate

i hope this made it easier to understand.

naikii ..good luck with your blueberry plants.next season you will have a bounty on hand.BTW what is your best tasting blueberries varieties?how about the yield?god bless you all.
Ahmed

Hey Ahmed, these are only first season plants, and so I dont have any yields from them as yet. In about 6-7 months, come spring I will let you know again! Thanks for the info

Have you checked the pH of your water after adding the vinegar? I have hard water w/ a heavy bicarbonate load and have to add at least 1/4 cup per gallon to get the pH under 6. Others get by with a tablespoon, which is what I used to do until I actually tested my water and found out that wasn't nearly enough. Also, is the chlorosis on the rabbiteyes primarily on new growth or are all of the leaves showing the symptoms? In the heat of summer (when temps are about 90 F), I occasionally see some chlorosis on new growth. Nonetheless, the plants usually work through that on their own and the symptoms abate once the weather cools down a bit. I know that you said that you were entering autumn and temps were quite cool, but I thought I'd mention it nonetheless.

I've included a link (below) to an Oregon State University newsletter that harvestman quoted in the Fruit forum thread that I mentioned above. Here are two excerpts that are especially intriguing:

Ammonium-nitrogen vs. nitrate-nitrogen. Many studies
have been conducted regarding which form of nitrogen
blueberries prefer. Studies in hydroponics and sand (I
would call this semi-hydroponics) growing systems,
blueberry plants do take up both ammonium-nitrogen and nitrate-nitrogen. However, in mineral soil production
systems (like in Oregon), blueberry plants that received
nitrate-nitrogen performed poorly compared to those
fertilized with ammonium-nitrogen. More recent studies
found that blueberry plants have limited nitrate reductase
activities, meaning the assimilation of nitrate in blueberry
plants could be limited. Therefore, blueberry plants
prefer the ammonium (NH4) form of nitrogen.

and...

The use of urea. When urea is applied in the soil, it will first break down to ammonium and carbonate by urease. This process takes one hydrogen ion away from the soil.
Then ammonium may form ammonia (NH3), so soil pH
close to the urea particles could increase markedly.
Although such a pH increase may be temporary, it could
induce iron chlorosis in blueberries. Because of the
eventual uptake of ammonium by blueberry plants, the
long-term effect of urea on soil pH will still be a
reduction in soil pH.

Since the fertilizer that you've been using doesn't include urea, the latter excerpt doesn't really apply. Nonetheless, it's interesting in that MG is urea-heavy.

One last suggestion -- you might want to try cross-posting this in the Fruit forum. Al offered good advice which could very well solve your problem, but there are a number of frequent posters over there who have a lot of experience with blueberries, which increases the odds that you'll catch the attention of someone who's seen a similar pattern in rabbiteyes, etc.

Here is a link that might be useful: Oregon Blueberry Newsletter

This post was edited by shazaam on Mon, Apr 8, 13 at 13:44

Thanks for your continued replies! I haven’t actually tested my water, however my town has a fairly high quality water supply, held in a high dam fed by rainwater. The water analysis from our water authority states average pH ranges from between 7.3-7.8, depending on one of our two dams. I haven’t added vinegar to my water each time, nor really accurately measured it, rather adopting an ‘about one good slosh to 9L’ measurement system. I suspect, with absolutely no evidence, that this drops water the pH to neutral, or a bit below, I fear burning the leaves with a too-acidic solution.

I think our weather has been cool enough that heat has not been a factor. The affected leaves are new growth, with old leaves looking largely fine. Thanks for the link, and I think I will cross post to the fruit forum in perhaps a week or so if conditions don’t seem to improve with my slight adjustments. Since I foliar fed some iron, as well as adding some to the soil, if it is an iron deficiency I would expect some improvement in about a week or so…