Blueberries - Having some problems

[pparham2010]

Hello,

About 9 years (or more) ago we planting a Highbush Blueberry in our back yard (typical beginner error - did not do any research on what they needed). It has been going strong producing what we thought was a good yield every year (6 - 10 pounds of berries). About 3 years ago i realized i had not been pruning the bush properly (or at all) and gave it a nice trim which cut back on the harvest the next 2 years. This year it was back in full bloom and my wife decided to add 2 more Highbush (1 on either side of the original) to expand our gardens.

The new bushes have been planted for about 2 months at this point and we started noticing some issues with the 1 new one (having some die off on a section of the bush (for lack of a better description - crispy leaves with dried/brown edges), the original bush has the leaves turning yellow/veiny, and the 3rd looks like it's starting to have the same issue with yellow/veiny leaves.

After a little research I, of course, found that it could be about 50 different things depending on who you talk to or what video/webpage you visit.

The location the Blueberries are planted in is fairly dense clay (typical of suburban lawns in Central Maryland).

I started with the basic soil test using a Rapidtest kit for NPK and pH. I tested the soil just below the surface and then again at about 8 inches deep. I know the Rapidtest can result in some inaccurate results but i have not been able to get any Soil testing places to actually send me out a test kit to get good lab results as of yet.

The Rapidtest results are as follows:

Surface: pH 6.0 - N High - P High - K High
8" Deep: pH 6.5 - N Low - P Medium - K Medium

Based on those results it seems like the pH is way too high in the area they are planted and gets worst the deeper it goes and the fact that the soil is junk clay probably doesn't help.

I know it would be best to get an actual lab test done and am currently waiting on the University of Delaware Extension to send my their testing kit. I would really like to wait for a solid test before i start messing with things too much but was trying to figure out if there was anything i could/should do to help the Blueberries. I have saved an amount of the existing soil from the area for the Lab test to get a baseline.

I am considering amending the soil around the root balls of the plants as a start (so i don't have to dig them up and disturb the roots) to a depth of about 10" - 12". Based on what I've seen online, I am thinking about using 50% existing soil with 40% peat and 10% compost to break up the Clay and get more organic matter into the area. I do not plan on adding any sulfur until i get the lab results but thought the peat could help to start bringing the pH down some. I would use the lab results/Rapidtest results from the existing soil to see what would be needed after the initial peat/compost addition.

Any helpful comments would be appreciated. Thanks.

Paul

 

[YumYum]

Surface: pH 6.0
8" Deep: pH 6.5

PH is too high. I bet your leaves look like this right? Yes that means the pH is too high causing an iron deficiency. Rapidtest may not be a precise test but close enough in this case.

Watering with city or well water (in most cases) will cause the pH to rise back to neutral levels in time. Skip the peat moss stuff and use elemental sulfur immediately. It only works by bacteria converting it to sulfuric acid which lowers the pH but bacteria are slow in Winter times. You can use other things to lower the pH faster but it can be more toxic.

 

[pparham2010]

Yes, the leaves on the original plant and the one new plant look like that.

The other new plant looks more like this.

Would Espoma Organic Soil Acidifier be a good choice for the sulfur? Ive had good results with their other products for my gardens.

Thanks again

 

[YumYum]

Yes that would work but if you don't need calcium in the soil then I'd look for a plain elemental sulfur product. I don't see one on Espomas website.

Dont feed blueberries nitrates as it is toxic to them. Use ammonium or urea types of nitrogen.

 

[Mystic Moon Tree]

If it crept from a new unquarunteened plant to another one it could be a root rot, so keep that in mind. You also increased the demand on the planter with the extra plants so yes you likely need to amend the soil & plant companion plants. As far as I know clay is not a huge detriment to blueberries. If their leaves got touched with any foliars spray or a regular plant's fertalizer they will do that real quick. So yes that Ph is too high. I would immediately sprinkle a 1/4th cup of lemon juice around each bush's roots & brew a pot of coffee. When it cools to room temp water all 3 bushes with it and add the coffee grounds from the filter into their soil as well. Sulfur I hear works too, but you don't want to use too much. I preffer the natural options. If it is a disease the sulfur may kill it off too. So I would add these companion plants depending on where you live & your climate: borrage, strawberry, false strawberry, lemon, orange, coffee, or other citrus. I do have clover near mine, but you have to keep it from overgrowing & choking things with periodic mowing & pruning. I just plant mine in a G&B blue ribbon potting mix after amending with citrus compost, lemon juice & coffee grounds. I mulch with their own leaf litter. They do like to be thinned of cross branches & dead sticks. You trim the dead sticks into small pieces and add that to the top mulch. They do tollerate oak leaf mulch piles as an insullator in the winter. They will die quickly if fertalized with any normal plant folliars spray treatment maneur, or compost. Their leaves are very sensitive to basic things being sprayed on them.

 

[pparham2010]

Yes that would work but if you don't need calcium in the soil then I'd look for a plain elemental sulfur product. I don't see one on Espomas website.

Dont feed blueberries nitrates as it is toxic to them. Use ammonium or urea types of nitrogen.

I thought i would give an update on the Soil Test results from the University of Delaware for the Blueberry bed.

Soil Lead came in at 44ppm

Looks like another case of Rapid Tests not really hitting the mark too well... RapidTest pH was 6.5(ish), lab test 5.4. I should probably pick up a better pH test kit for the quick checks.

I already amended the soil around the root balls with a mix of Peat Moss (50%), Leafgro Soil Conditioner (10%) and native clay soil (40%) to get more organic material into the clay and improve drainage. I also added some Elemental Sulfur (about half the bag recommendations) worked into the top few inches of the amended soil.

Time to address the Phosphorus and Potassium.

Thanks again for your help in this.

Paul

 

[YumYum]

You may already know this but see the buffer pH at 7.5. That means your soils pH level will want to rise back up in time even though you add acid to the soil. Just something to keep in mind for the blueberries.

 

[pparham2010]

What i found strange was the pH results from the lab at 5.4 for the original unamended clay soil. Based on the rapid tests i would have expected it to be higher in the 6-6.5 range which is what i was using to base my initial amendments on. Hopefully the added sulfur will just help to hold the pH in that low to mid 5 range which i can live with considering the close to 10lbs of blueberries we got from the bush this year. I was mainly worried about the leaves browning and yellowing cause it looked like there was a big issue... I did follow the labs recommendations and amended the soil with Triple Phosphate and Urea, I did not add any lime yet but i plan on picking that up over the weekend.

Thanks again for your input with this, the learning curve has been interesting this year lol

 

[YumYum]

With blueberries when the pH starts getting too high, the first sign is iron chlorosis. It could also mean a shortage of iron but usually the pH is too high for the plant to uptake the iron in the soil.

Iron chlorosis: