[pepsi100]

I have just got hold of three blueberry plants
I want to goive them the best start in life for their first year
So they will be inside in pots over the winter
I have potted them in John Innes no3 ferilizer
I have heard that I can add coffee grounds to the soil to  make it more acid
Now I dont know how true this is, but I have been adding it to my blueberries outside, okay they are only 2 years old, but seem to be doing okay
They get watered by the hose when the wife waters the grass and plants (I am trying to get her to use rainwater on the new blueberries in doors)
Well any advice for helping my new blueberry plants make it through their first year would be appreciated

[JayG]

They need to be in ericaceous compost rather than John Innes no3, which will almost certainly contain lime.

As for watering, rainwater is ideal, although if you live in a soft water area you can get away with tap water, at least in the short term.

Useful link for checking whether your supply is soft or hard: https://www.aquacure.co.uk/knowledge-base/uk-hard-water-map/

Any added fertiliser, which shouldn't be needed until next year, should be a type specified for ericaceous plants.

[pepsi100]

Thanks for your reply (and the link)

Apparantly I live in a very hard water area (I'm surprised I am still alive after reading about it)

And apologies about the John Innes, its number two I have used, so that looks fine

I have bought a 1Kg box of Sulphate of Iron fertilizer for use next year

I have got hold of a bag of coffee grounds (about 20kgs) from Costa coffee (they just throw them out and do so every day)

I was going to add them to the soil on my blueberries in the garden, I heard it helps to make the soil more acidic (if not I can just throiw it in my compost bin)

My new blueberrie plants will go outside about March/April time I reckon

[JayG]

And apologies about the John Innes, its number two I have used, so that looks fine

Afraid they won't like JI number 2 either (chalk is one of the ingredients) - there is a John Innes ericaceous compost available which is probably the best option, although any ericaceous compost would do.

[pepsi100]

Oh, dear, they arent getting off to a very good start are they ?

Well too late to do anything now, I will just hope they survive the winter and then they can go outside

I'll dig a hole and fill it with my compost and a good filling of ericaceous compost (bound to be some in the garden center at some point)

[JayG]

Coincidentally, I picked the last of my blueberries this afternoon, and the leaves are already turning red, so they are starting to shut down for winter now.

Hopefully yours are too, and won't notice what's in the compost before you change it next spring. 

[pepsi100]

The leaves on the one's outside have turned red and will probably fall over the next few days,
when the frost starts they will be under a fleece and then just hibernate until the spring

The ones indoors are still green, no signs of dropping, but its warmer in the conservatory by a good few degrees

Got two bags of that ericaceous compost ready for when they go in the garden, (homebase had a deal, buy two for a tenner)

[pepsi100]

JayG

What are your thought on adding coffee grounds to the soil for Blueberries ?

[JayG]

Organic materials produce weak acids as they decompose, but finish up more or less neutral - very few produce enough acid to make much difference to the soil pH, sphagnum peat moss being a notable exception.
(I use an annual dressing of sulphur chips to help keep the pH low in my blueberry patch.)

Seeing as you've already got them, you may as well use your spent coffee grounds as a mulch - when you get your blueberries into ericaceous compost they should be ok anyway.

[pepsi100]

As you say, I have got the coffee grounds now, so I'll just put it as a top dressing, cant see it hurting

Ive got a bag of sulphur chips in the shed somewhere

Thanks for your reply

[Grubbypaws]

JayG how much of the sulphur chips do you use per plant? Mine are in large containers and I am not sure how much to apply and when.

[pepsi100]

Grubbypaws

On the pack I got it says 30-35 grams per meter, how you work that out for a pot I have no idea
Mine are about a year old at a guesstimate

[JayG]

JayG how much of the sulphur chips do you use per plant? Mine are in large containers and I am not sure how much to apply and when.

I check the soil pH with a (cheapo) chemical test kit, and if it's around 5 I just give a light sprinkling around each plant (maybe a rounded tablespoonful) and tickle it in with a hand fork. Best to do it in spring when the soil is starting to warm up as it takes a long time for soil microbes to activate it and there's not much activity in winter.
(If it's above 5 I usually repeat the dose in mid summer.)

[pepsi100]

Where do you get these test kits?
I've never seen one

[JayG]

https://www.amazon.co.uk/Verve-Soil-pH-Tester-Garden/dp/B07MZ5JCN8/ref=sr_1_79?crid=B7IMNM7A2API&dchild=1&keywords=soil+ph+testing+kit&qid=1632836725&sprefix=soil+pH%2Caps%2C281&sr=8-79

Although the above is B&Q's Verve brand I can't actually find it on their own website, so can't guarantee you will find it at your local branch.
Lots of others available (just don't buy a cheap soil pH meter - I'm not saying none of them work but which ones actually do is impossible to say with any certainty.  )