Blueberries fertilizing during fruiting?

All the berries we harvested from our yard taste much sourer and sweet after-taste. They were ripe and purple and blue in color. They are also much firmer.

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Quite ordinary in taste, but I like ‘Sunshine Blue’…easy to grow, tolerates clay and higher pH soils…simi-evergreen with a blue-green leaf color like some of the Rabbiteye plants.

I’ll look for a reply later, I need to log off and do some work. :smile:

I fertilize with Milorganite works better than anything else! Cheap too! I’m all about that.
Well I know how to spend in excess too!
I’m all about flavor and most of my blueberries are really good. I’m willing to sacrifice production for flavor. I tried to grow Sweetcrisp here as it is exceptional. All I managed was to keep it barely alive. It finally died. It wants to go way too early for my zone. Many big berried types out there, all are pretty good too. I have Chandler, I like it. It got better with age. KaBluey the silly named one, is excellent as is Cara’s Choice. As are so many others too.
This winter in store from Chile, the blueberries we got were very good. A lot of locals grow them, it’s one of our main crops so most commercial blueberries here are awesome.
I don’t fertilize heavy, but when they are slow to grow I do give them more. Seems to me they need pushing. I have not had good results just using organics. I have with other plants, just not blueberries.

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What I do is 1-2 small applications of Elemental Sulfur (if pH needs to be lowered) and 3-4 apps of Ammonium Sulfate

My schedule is like this:

  • Shortly before or after bud break test soil pH, if pH needs to be lowered apply Elemental Sulfur and then apply Ammonium Sulfate (~1tbsp / plant - age dependent) - I just sprinkle the dissolvable granules wide around the base
  • Do 2-3 more Amm. Sulfate applications, evenly spread out through the growing season stopping before late summer
  • Also in late summer, if you think you need to further lower pH you can test soil pH and apply Elemental Sulfur again

When I used it Holly Tone appeared to basically be Milorganite (or similar organic fert) mixed with a small amount of Elemental Sulfur, kind of a ripoff IMO.

You might find this also find this post / thread useful:

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We all do things somehow differently. I guess we all can find the justifications for such.

I have one+ acre lawn area. My neighbor hires full time landscaper and they spend like $4,000 or so each year. I guess their lawn looks better, not many dandelions as ours. The have no children and only a dog in their fenced area. They do not play with their dog in the backyard. So the lawn is mostly for the looking.

I used to fertilize my lawn by myself. Maybe $1,000 each year. I stopped doing it quite a few years ago since I know I’m fighting the mother nature on the weeds etc. Weeds do not bother me any more and I find that more natural looking. I still mow the lawn on a regular basis, but mainly a naturally looking lawn. I thought about returning some of the lawn area to meadowland. But all the woody plants made me pause that plan.

As for the blueberries, wife just bought two bags of 25 lbs of Holly-tone. $15 each to a total of $30. I think that is pretty much all I need for the season for all my blueberry, fig, and other fruit trees. I sprinkle about one cup on the base in late spring like now. And one more time over summer after fruiting. Similar with fig plants, one in spring and one over summer. I do not like fruiting plants to have lush and robust growth. So I control the N.

Sure I can get Milogranite, urea or bone meal, blood meal and feather meal to mix my own organic fertilizer. Worth the hassles to do that? Probably not for me. So I would not say that Holy-tome is a rip-off.

Certainly for the people who are doing commercial farming, or need bulk fertilizers, all those “organic” things would not make sense. But as a hobbyist and for own consumption, I’m happy to spend $30 to $50 a year. It saves time too. So I do not need to carry all the ingredients to next year, or ruined by the cold, moisture and by the animals seeking shelter in my shed.


To clarify, I wasn’t suggesting you mix your own Holly-tone. I believe I was previously buying the small bags of the Espoma 6 lb. Organic Soil Acidifier for like $10 which isn’t worth it. IMO if your soil acidity is fine (and it really doesn’t have to be that low) you can get away with just doing small applications of Ammonium Sulfate for blueberries.

What I use now is Elemental Sulfur Pellets (2 LB for $10) to lower acidity, Hi-Yield Ammonium Sulfate (4 LB for $15) which gives you your nitrogen (N) and then you optionally need some source of phosphorus ( P) and potassium (K). The Sulfur and Sulfate I have only used up like 70% of in two years for 5 medium bushes - it really goes a long way.

For everything else in my yard I use FLORIKAN 18-5-12 NPK PLUS, 140-DAY FORMULA. Its more so designed for potted plants but because its so easy to use I have used it for everything from starting seedlings to fertilizing flowers and fruit trees (which probably don’t need it). It was around $100 with shipping but one bag has lasted me 3 years now.

At the end of the day if you’re getting good results without too much effort it doesn’t matter if you are spending +/- $100 per year. There’s definitely a point of diminishing returns with fertilizer.

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Ammonium Sulfate is the perfect Blueberry fertilizer for my area until PH gets too low. Works great in drip irrigation too. It’s cheap at my local farm supply store that blends fertilizer too. A small amount produces growth on the plants quickly especially with fertigation.

After using it for a number of years my PH fell to 4.0 so I shifted to a 17/17/17 blended fertilizer.


On recommendations from forum members here, I have a choice of a bunch of fertilizer to bring my 6 plants up to speed. When you are new with growing blueberry you go out of your way to do whatever it takes to get success.
My citrus collection requires Peters 25 / 5 /15 HP (acidic) that’s what I going to try. Still use Cottonseed meal. Cover all with pine needles mulch. Last year my small plants didn’t do nothing, this spring they all survive and growing good.

That may be okay,but it’s a little high in the Nitrate part of the Nitrogen.I use their 21-7-7 Acid.They also make one,that was developed for Blueberries,but is suppose to work for most berry plants,Berry Special 25-9-17.

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Brady, I bought a 25 lb bag of Peters, it’s will last a while. Got to use that with a light dose.

I sort of agree. Hollytone, for instance, doesn’t cause them to thrive. But it does help them survive. Fertilizer that contains lots of nitrogen isn’t good for the berries during fruiting (and too much doesn’t seem to be good for the plants anytime). Adding
P and K and Fe and other nutrients in moderation should not impact fruits much.

I’d like to make leafmold, but I am afraid it will include pathogen infected leaves.

It seems to me that people do not utilize the huge amount of information put out by the state extension services. That is the first place I search for information on fruit trees. A search of “fertilizing blueberry plants .edu” gives a huge amount of results. It looks like Duck-Duck Go gives better search results than Google in this case.

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I fertilize mine with hollytone early spring at bud swell or just before.

Then again as soon as last fruit harvested. I dont have any late varieties… so that is mid july for me.

I just started the 2x a year a couple years ago and i am seeing good growth and berry crops.

My 7 ft tall tifblue… got frosted mid march… two nights back to back… lost about 1/3 berry crop.

My two climax bushes are loaded… just a few starting to turn blue now.

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I fertilize my blueberry bushes according to the recommendations of AgriService BC:

Field age of plants N (g/plant) 21-0-0 (g/plant) 1/3 of Previous ml
1 6 28.8 9.6 8.8
2 8.5 40.8 13.6 12.5
3 14 67.2 22.4 20.6
4 23 110.4 36.8 33.8
5 28 134.4 44.8 41.2
6 31 148.8 49.6 45.6
7 40 192 64 58.9
8* 45 216 72 66.2

Plants older than 8 years may require up to 61 g/plant (293 g of 21-0-0 per plant). Note that the recommendations only covered the first 2 columns of the table; I calculated the last 3 columns (ml is the amount in milliliters to apply at each monthly application.

As recommended by an Oregon agriculture website, I apply the recommended nitrogen three times a year, in April around blooming time, May, and June. No fertilizer should be applied after June.


What do people think of giving blueberries Epsom Salt. My brother told me he is using Epsom Salt for his fruit trees, so I bought some, I now want to get rid of it because I don’t have a lot of storage.

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A small dose isn’t going to hurt anything…but a soil test is in order if thinking of using it in a big way. Sulphur is the best option to lower pH…but sandy soils do often leach out their magnesium, but it’s a guessing game if no soil test has been performed.

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I’m too lazy or cheap to do the soil test. I have clay soil, but maybe I’ll sprinkle a bit at a time to get rid of the bag. I want to get to a stage where fertilizing my fruit trees is simpler. I think I bought a bunch of fertilizers for trying them out, but now I found an easier way.Howver, I don’t want to throw them away other.

Many blueberries don’t like clay. So good luck.

*Adding organic matter helps of course.
And I’ve found Sunshine Blue to be pretty tolerant of clay and also higher pH than most.


I’m going to add more Sunshine Blueberry. I do add a lot of garden soil from Costco and that seems to help.

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