Please guide either its nutrient deficiency or fungicide?

[Usaf]

1) Here my Cestrum nocturnum plant purchased recently it was fine in start but as Transferred into another pot and added more soil later it started leaving its leaves and now turning brown. I think it’s a fungicide but seniors may tell better.
2) Zinnia is not getting bigger and now its leaves/branches started dying and turning brown.
3) 3 days ago i purchase marwa plants looks healthy but now its flower started drying. i have/had very bad experience from nursery purchase.
But the good thing is portulaca grandiflora which started from seed is growing well in abandoned wash basin. I called it disease plant once you sow its seed into soil and it gets double and double.

[newton]

ASA

There are several factors that could be responsible for the symptoms that your plants are showing, in order to establish a link or likely cause then please advise on the following:

What is the basic mixture of your potting soil media? (poor quality soil can produce bad results)
What if any extra fertilizers or manure have you added to your soil media? (too much or fresh manure/fertilizer can cause plant burns, young plants are particularly sensitive)
Where are your plants sited? ie in full sun, or shade, wind blown, hot or overly humid area etc (These factors or a sudden change of them can cause some plants stress and failure to thrive)
What is your watering regimen, (waterlogged pots can limit or drown plant roots and the effects are seen later above ground)
When you repotted the plants and/or added soil did you keep the plants at the same depth or not? (burying the shoots or main stems with extra soil can often cause many plants to sulk or rot the stems leading to fungicidal infections)

[Muhammad Arif Khan]

This is the time of the year when you neither purchase nor transplant your plants.

[mikhurram]

Rightly pointed out by Brig Sahib as this is the time of the year when ensuring the survival of plants is an uphill task at 45'C. It's obvious that the plant is suffering from a transplant shock.

Plants should only be transplanted either after the monsoon spell or in spring (March/April).

[drgenetix]

Hi bought Cestrum nocturnum plant 2 months back. Its only about a foot tall and does not seem to have grown since I bought it. I have kept it in a pot which is well drained and the soil quality is good. I have also used a very dilute urine compost once. I was thinking of transferring it to a bigger pot, but after reading the posts, I think it is not good time to do so. My questions:

1- Is it a slow growing plant?
2- Do I need to use any fungicide/pesticide?
3- The plant has 3 major stems growing one of which is long thin and does not bear any leaf. Should I chop it of from the bottom?
4- How often should I use compost on such small plant?