how to calculate sulphur requirements to lower pH

Good afternoon all. Does anyone know a formula for working out how much weight of sulphur chips I'll need to buy if I want to take a patch of soil of given surface area and depth from pH 7 down to pH5?

I know soil type matters in such calculations, so mine is mostly clay/loam.

I have blueberries in containers, but I went to set them loose.

 

Sorry C1, dunno the answer, although I have seen rates posted on the web.

I will be very interested to hear if you manage to get Blueberries growing in your soil by just adjusting acidity with Sulphur, 'coz I'd definitely be up for trying that

 

I use aluminium sulphate.
The dosage is on the box.

Are sulphur chips not inert?

 

After reading many and varied articles, I came to the conclusion that nobody really knows a reliable formula, but consolidating everything I read, I calculated that I would need somewhere between 1lb and 5lb for the 28 square foot patch I want to take from pH7 to pH5. So I order 2.5kg, which is just over 5lb. I figured that as there's 50p difference between the price of the 1kg bag and the 2.5kg bag from the same supplier, I may as well go for the larger measure.

It apparently takes several months to work, which makes sense as you have to allow time for the moisture in the ground to react with the chips to make sulphuric acid, so I figured on doing it now with a view to taking readings in late winter, and planting out in spring.

There were several options, aluminium sulphate, some salt of iron (can't remember its name), sulphur chips and sulphur powder. From everything I read, sulphur seemed to be the most popular option, partly due to cost, and partly for reliability (other options seemed to come with risks of causing deficiencies of other nutrients by binding with other chemicals in the soil).

So sulphur it was going to be, which then came down to chips vs powder. It is claimed that powder works faster, which again makes sense as the greater surface area will speed up the reaction, but I also figured there was an extra risk that I didn't like. Powder blows on the breeze, and as sulphur reacts with water to make a very nasty acid, and water occurs naturally in our digestive tracts and the surface of our eyes, and I have two young kids, I figured I'd accept the slower reaction of chips, which are big enough and heavy enough to not blow on the breeze or be inhaled. They will be worked into the top 1ft or so of soil in the bed in question. Rain water will naturally carry the resulting acid deeper, which in theory will benefit the blueberries which already have good rootballs in their large containers.

I am aware that there is a risk to the plants if I get the pH wrong, so I have a plan for that. After taking several pH readings prior to planting, as an extra precaution I plan to dig their holes a lot bigger than they need, and then line the holes with ordinary ericaceous compost to serve as a buffer zone between existing roots and potentially too potent (or not potent enough) acid soil.

Of course there is a chance that the whole project could fail miserably, but is that not part of the excitement of science?

 

Sounds like a sound plan C1 ... good luck, and look forward to hearing how it goes.

 

I use sulphur quite a lot around certain plants, mostly powder, I've run out of chips.
I usually apply it during winter when its wet.

I trhink you need to keep adding it at a slow rate, to build up the acidity slowly, its not a fast process.
I still use chelated iron in spring should the plants start to look sick.
This works much faster, but is short term.

I'm a bit unsure that you will get a true ph reading by the spring, the chips take quite a while to break down.

 

@clueless1

It's iron sulphate.
Powdered sulphur works quicker than chips due to the greater surface area. Sulphur is pretty harmless and I wouldn't be overly worried about ill effects. It was used medicinally for skin conditions and my father was regularly dosed with sulphur and treacle as a child. In the soil it is slowly oxidised by bacteria to sulphuric acid, which is why it works quicker in warm weather.
This link has some useful information about action and amounts, although on a much larger scale, http://blueberries.msu.edu/uploads/files/Lowering_Soil_pH_with_Sulfur.pdf
I would steer clear of aluminium sulphate due to the possible build up of aluminium in the soil.

 

Just been out there and noticed that the sulphur chips I put down have already disintegrated. That patch of ground now has a light covering of greeny yellow dust. I didn't think it would happen that quickly. I'm just going to dig the lot in now and see what happens.