We have got all sorts of spare plants kicking around at the moment .. from seedlings to small plants. Tomatoes, sweet peppers, geraniums, chilli plants etc .. more than likely we will compost the lot fairly soon, as we have sufficient planted out.
The one thing they all have in common is you can put two fingers either side of the stem and turn the pots upside down, then remove the pot. All of them are bone dry on the surface, but only the lower roots are moist.
The compost should stay held together by the roots, if it crumbles or collapses, it is too wet.
When you are spraying the Aphids on the stems, just mist the surface of the soil, don't saturate it ..
It is much easier to add water than it is to remove it !
This is what your soil should look like .. just a spare geranium.
https://ibb.co/DVZdXVB