Yes we added sulfur after the soil test came back slightly higher than 7 in the planting holes where plant growth of blueberries was anemic. We never used rotten sawdust in pots or potting holes again.
We only use the soil conditioner product now. The SHB in the field got Pete moss, soil conditioner and sulfur. The SHB for resale in containers are planted in 100% soil conditioner and fertilized with Ammonium Sulfate. Growth is good and we have never tested the PH in the pots.
Horticulture provides lots of unexplainable surprises for me. It keeps it interesting. I’ve never evaluated the pH of rotten wood though. Maybe it changes to more acidic as it decomposes. Where I’ve seen sawdust used for blueberries it was always from a lumberyard that mostly cuts soft (conifer) wood.
quite strange indeed, if soil and water are acidic, rotten organic material should result in a dip of pH or at the least keep the status quo, but never increase pH. It will only increase the pH if the rotten material actually has higher pH than both the soil and the water( possible but not probable, unless you are situated in certain regions of brazil or a peat-rich swamp).
if you have litmus paper, you can check the pH of the decomposing sawdust you are using, regardless of whether or not it is hardwood, it should be less than 7.
anything that has sweets in it(cellulose/starch/etc) should end up sour as they get metabolized by microbes.
my soil here runs at 6 and i have been mulching with strait hardwood sawdust from a firewood seller for 6yrs. here. ph has remained the same so i add a sprinkle of pelletized sulfur, about 1/4 c. per bush and ph stays around 5 so far . never amended w/ sand in my heavy clay but did add quite a bit of strait peat to the soil before planting my blueberries. they were planted on mounds but over the last 4 yrs the mounds are now slight depressions as the peat broke down. every spring i add a couple in. of peat w/ a little suffer and mulch w/ 3in. of fresh sawdust. my blueberries /lingonberries are happy.
Were your Lingonberries planted and if so,how long did they take to fruit?
I’ve had the variety,Koralle,for a number of years,first in the ground,where they were getting overcome by grass.I moved them to a wide,fairly shallow,plastic container,that fit on a half whiskey barrel.
Flowers only,so far.bb
The extension agent was surprised too since he suggested the rotten sawdust. He tested the soil at the base of some of the 1200 blueberry plants that were doing poor. This was out first attempt at commercial growing and we got off to a bad start. It took a while for the sulfur to work but by the next spring the plants looked better and started to grow properly
Used to have a lot of local sawmills where rotten sawdust was plentiful but they are gone and so is the sawdust so we never used the rotten sawdust in the planting holes again.
mine are 3 years old but i fertilized them too much last spring and got a lot of growth/flowers but no fruit. read after the fact that they rarely need fertilizer. hopefully i get some next year. i have 6 koralle, magenta and red pearl.
My understanding is that they are fairly heavy feeders on nitrogen, and often require it for good fruit production. Overfeeding them with N., according to this guide, leads to stunting growth, not to excessive vegetative growth- not saying you are wrong, but this is another opinion.
I feed my blueberries a lot of my urine in the spring and they are always very productive plants.
Where I live blueberries grow wild, frequently beneath mixed pine/oak forest as an understory bush. No brush fires for a while, so its just a very deep layer of leaves and needles and branches slowly decomposing. The container mixes you posted seem to be appropriately rich in organic matter, so that shouldn’t be a huge issue. I’d definitely mix in pine, or mulch with it. I think they really love more acidic soil?
Maine is known for its wild low bush blueberries, blueberry barrens and black acidic soil. all our evergreens produce this type of soil so when i planted my blueberries and lingonberries i incorporated composted needle mulch into my soil before planting. keeps the ph around 5 and the weeds can’t compete . i then mulch with 3in. of spruce sawdust