Turning pink hydrangeas into blue with a coffee trick.
Found out from @gardendujour that you can dye pink hydrangea's blue with coffee grounds and not have it negatively effect the wildlife, has anyone else tried this? If it actually works I'd love to try it out in my garden.
Some hydrangea varieties will produce blue or purple flowers when grown in acidic soil, and pink or red flowers on alkaline soils. Adding coffee grinds to your soil will increase the acidity, so there’s a chance the flowers will turn blue. You’re not dyeing the flowers – they’re just responding to soil conditions.
Hilltoptree
Yes it works.
For me it didn’t kill the hydrangea even if you put a lot in. (I am talking about 2-3cm deep covering the surface in a 40cm dia pot).
So i had run a little lack of control test this year.
I had only one pot without coffee grounds.
But they all got the acid treatment.
Different pots get a weekly equal spoon of Citric acid (because it was cheap) and Aluminium sulphate (More
Expensive).
So the results was
aluminium sulphate+coffee the blue was more intense. Almost too blue.
Citric acid +coffee gave blue but some seems to be pale.
Citric acid+ zero coffee grounds and got pink.
I also insomniac read a journal paper explain the chemistry/physics of it…it’s the acidic environment triggering something allowing the aluminium ions already naturally in the flower turning on the blue switch.
It even said an acid spray on the flower can turn pink to blue.
AdPale5633
I didn’t know about coffee! I have a pink hydrangea, but for two years running I have the same random blue flower in the middle.
anodos999
There are so many gatekeeper butterflies this year!
stuntedmonk
You can put iron around it to change colours too. A classic is old nails
5 Comments
Some hydrangea varieties will produce blue or purple flowers when grown in acidic soil, and pink or red flowers on alkaline soils. Adding coffee grinds to your soil will increase the acidity, so there’s a chance the flowers will turn blue. You’re not dyeing the flowers – they’re just responding to soil conditions.
Yes it works.
For me it didn’t kill the hydrangea even if you put a lot in. (I am talking about 2-3cm deep covering the surface in a 40cm dia pot).
So i had run a little lack of control test this year.
I had only one pot without coffee grounds.
But they all got the acid treatment.
Different pots get a weekly equal spoon of Citric acid (because it was cheap) and Aluminium sulphate (More
Expensive).
So the results was
aluminium sulphate+coffee the blue was more intense. Almost too blue.
Citric acid +coffee gave blue but some seems to be pale.
Citric acid+ zero coffee grounds and got pink.
I also insomniac read a journal paper explain the chemistry/physics of it…it’s the acidic environment triggering something allowing the aluminium ions already naturally in the flower turning on the blue switch.
It even said an acid spray on the flower can turn pink to blue.
I didn’t know about coffee! I have a pink hydrangea, but for two years running I have the same random blue flower in the middle.
There are so many gatekeeper butterflies this year!
You can put iron around it to change colours too. A classic is old nails