This happened quite a few years ago and it's definitely not as colourful as someone else's story on here and I'm really sceptical about all things ghostly and think that's why I've settled with some sort of a rational explanation to this.
I've heard of and read about plenty of stories about things/plants being affected by a person ('s life). And apparenty it's quite common but one thing that happened was when my step grandfather died. The clock at home stopped exactly at the same minute as he died in the hospital. I was too little to remember anything else from that time. But I was about 17 when my grandmother passed away. We had a cactus. It wasn't your typical "thorny piece of plant". It had sort of leaves with prickles. And it blossomed quite frequently. Well, at least when my grandmother was alive. Long story short, the vitality of the cactus corresponded to my grandmother's health. When she went to hospital the cactus was drying.
Eventually, when my grandmother got really sick and died, so did the cactus. There was nothing we could do to revive the flower. It just died with my grandmother. I can't say we're a spiritual family or even emotional family but things got a bit out of balance after the death. And strange things started happening. My mother blamed it on the weather. My grandmother died on the 12th of December, in winter. So everything that happened at home my mother said it was cause of the weather, that it was really cold out. Maybe, maybe not, but stuff like this never happened before nor after the death and that time.
All sorts of electrical equipment started acting up. We had two TVs at the time, they both broke. My stereo broke about three times. My VCR broke. The bulbs in my lamp broke several times and lamps in other rooms, especially in the kitchen and in the bathroom started flickering.
It only lasted for a short period of time. It didn't last all winter. But it started after my grandmother died. And one day it all just stopped. Well, I count the end of the flickering lights the end of it all. Maybe it was the cold winter, but as I said we've had colder weather after the death and nothing has broken down like that, nor have the lights flickered.
And I remember at the time I was really paranoid that it might be my grandmother's ghost behind it all. I was really scared at night and I stayed up really late so that when I turned off the light I'd fall asleep straight away.
I remember one night I was very nervous and I kept waking up. So this one time before I closed my eyes, I was just looking at the table and armchair in front of my bed and fell asleep. Now, I don't know if it was a psychological thing or paranormal but a very realistic dream occured (I was definitely fast asleep, not awake and it definitely wasn't sleep paralysis even though I had a few of those at the time but it was definitely because of nerves). Anyway, I dreamed I was still in my bed, looking at the table and the armchair, except in my dream my grandmother was in the armchair. She looked sort of angry, then she told me, in a warning tone, to start going to bed earlier not to mess up my health. Next second I woke up.
I was sort of relieved but scared at the same time since I didn't know if it was really my grandmother talking to me or if it was just my imagination looking for a way to calm down. I started going to bed at decent hour.
Funny thing is... When my grandmother was still alive we used to joke about her haunting. We just kept saying whatever happens don't come to haunt us cause it'll freak us out.
You didn't mention if your grandmother lived with your family. If she did -
Is it possible she had a special plant food she gave the cactus? We inherited my partner's grandmother's African Violet a couple years ago. We were told it was a fussy little plant. I looked up a couple things online, and it's flourished... Maybe your grandmother knew something about cactuses you don't?
The lights - she also might have changed the bulbs when they went out, and once she was gone, you noticed they needed changing more.
*shrug* That's all I've got.