I suppose most of you would likely have this common question to me.
What do you put in the pot that causes the roses to bloom with pretty flowers? How do you start?
Just to give you an idea, I made a simple diagram for ease of understanding.
Basically the purpose of the coconut mulch and charcoal is simply to hold the soil and prevent the soil from escaping through the drainage holes. Charcoal is good material against fungal infection.
Based on experiences so far, it is best to mix soil with grass cuttings, a ratio of 9:1 would be sufficient before you transplant your roses into the soil. The purpose of this is to improve drainage and also to kick start the microbes activities beneath the soil. The new bag of soil that you got from your gardening shop is very likely had been dormant for couple of weeks, so by mixing grass cuttings into the soil, you induced (or 'instigate') the soil bacterias into action. Grass cuttings (dried type) is excellent source of nitrogen too.
Believe me, it really does make a difference. Even if you purchased a ready pre-mixed soil, it is still more effective to add in grass cuttings (of 1/10 portion) as you transplant. It also helps to improve the soil structure, especially to counter the heavy showers of rain.
As the rose is being transplanted, you may want to loosened some of the roots from the root ball. However do not attempt to remove the soil attached in the root ball. The last time I did that, my rose 'layu' the next day. There are probably millions of micro-organism living in the root ball that aids in nourishing the plant roots. You don't want to mess with them. These micro-organism forms an unusual Symbiotic relationship with the plant roots. Both needs each other to co-exist. Removing the dirt from the root ball is not doing a favour to your plants. It suffers when you break the mutual relationships.
Lastly I want to share is the Top Soil Layer. This is the most important ingredient or recipe for good flowers. I don't think I can share everything within a single posting as I am still learning the trade. However I like to share the purpose of dividing an equal ratio of peat moss and grass cuttings. The main reason is to form better aeration at the top layer. If too much peat moss, it tends to tightened the top layer thus reduces soil aeration and increases excess moisture retention. At such a rainy season, maintaining a ratio of 1:1 (peat moss and grass cuttings) is better.
It is necessary to have sufficient peat moss too, because it aids in decomposition of organic fertilizer. I will reserve my suggestions on fertilizer mix in future postings. Having said that, it is important to note when transplanting, the root ball has to be planted at least 5 cm below the container brim. This is to allow sufficient depth for your top soil mix.
I will conclude this here. If you are considering transplanting, try this mixture. Hope it works for you!!! I believe it will!!