Choosing the Right Compost
When it comes down to choosing the right compost for indoor plants the selection on offer can be a little daunting. With so many different types on the market these days you can be forgiven for just opting for the first one you see and hoping for the best. However, if you bear a few points in mind when making your purchases, a specific compost for the job can sometimes make all the difference.
I will deal with one very specific growing medium to begin with and that is the one for orchids. There is no alternative here, you do need to buy one specially formulated for orchids. This may be a coco husk mix or possibly bark but so long as it says it is for orchids on the bag then you are ok. Ordinary peat or soil-based composts will eventually rot off the roots of orchids so avoid them at all costs.
As a rule a multi-purpose or general purpose compost will usually be ok for most houseplants but there are certain factors to bear in mind. Many composts now contain a wetting agent which is great for your baskets and tubs outdoors, that can dry out very quickly, but would be a steady death sentence to plants which need to dry out slightly in between waterings. Plants like cacti and succulents need a well-drained compost so choose a specifically formulated mix, which contains added grit for improved drainage qualities. Alternatively use a general purpose compost (without wetting agents) and mix with horticultural grit at about a 50/50 ratio.
For acid-loving plants such as azaleas and gardenias, choose a lime-free compost. Look for one that says “Ericaceous” on the bag.
Citrus plants, carnivorous plants and bonsai all have their own specific composts, specially formulated to help you to get the best from your indoors plants.