Why are all my plants dying?

[AsterMelody]

Hey, I'm new to growing plants as a whole so sorry if I have some dumb questions. I've recently started trying to grow various plants on my window-sil, to little success... Varieties of aster, mint and other herbs, vegetable sprouts, cat-grass, and more have all slowly shriveled up and died in my care and I can't figure out why!

Here's an example; I got a medium potted plant from Bunnings, I think it was a Melampodium Leucanthum. Anyways, I bought it and very carefully monitored the humidity and levels of fertilizer for a week or so. After this week, the flowers started to shrivel up and dry out at the stem, eventually leading to the stems drying out and snapping off... Worried, I flushed out the soil with new water and eventually put it out of the pot and into my garden. It eventually died, and I was quite upset.

This has happened over and over again with such a wide variety of plants and I don't understand what's going wrong!
I often worry about my plants and care too much about them so I have often over-watered them, so I changed to using a spray bottle to water when they're dry. Even then, I made sure to give them a proper water when the soil was dry.
I'm sorry for this long post, I just wanted to understand what's been happening. Maybe it's the weather where I live? Maybe I have to grow these outside? I'm not sure...

The spray bottle I used broke so I've just been giving them normal amounts of water, and keeping care to give my plants the correct amount of water. I make sure the water is drained properly and flushes through the roots well. I try to make sure that the plants get the right amount of sunlight - they sit on my window-sil and get around 5 hours of sunlight each day. Every 2 weeks, I give them some fresh air outside and flush their water properly. I've run out of fertiliser, so I haven't been using that as much as I should have been...

I got some small bench-top pots of herbs (mint and parsley) and today I noticed the leaves wilting and looking very upset, and I'm worried they're going to die like the rest of my plants...

 

[oneeye]

If you learn how to use an EC or TDS meter you will know what you are doing or whats in the soil. The difference between someone that knows what they are doing and someone that doesn't is the one that knows uses an EC meter and pH meter. I recommend to anyone wanting to learn how to grow indoor plants get them both. Makes gardening so much easier.

 

[big rockpile]

Read your post and I'm thinking over water and feed.

I am now using an Organic Fertilizer that is to be good for 12 weeks been guilty of over watering inside depends on size of pot and how warm it is. Some plants every 3 days and some once a week.

I know PH should be around 6 but I water so much I just use Tap Water it is around 8 but plants seem to do well.

All mine now are outside and doing well but it got so Hot I moved them to the shade.

Plants actually need very little Fertilizer they tend to go through picking what they need but can get too much in the soil and say the heck with this and shut down and die.

As far as water if they get too much they will actually drown. They need Oxygen.

big rockpile

 

[Tetters]

Hiya @AsterMelody. Welcome to the forums.
First of all, whereabouts are you in Australia? The weather conditions can differ hugely wherever you are. My kids in Queensland are usually rather warmer than the ones in Tasmania.
The next question is - have you got some outside space to grow in, or are you in an apartment? I wonder as you seem only to be growing things inside in pots.
Once we know these circumstances, we'll probably be able to work out the next step towards some successful growing.
Never give up - the best lessons are always learned by mistakes - we've all found that out I'm sure !