Working out the right soil mix for your plants seems like an overwhelming decision, with lots of conflicting advice online.
But once you get to know what your plants need, and stock up on a few ingredients, it’s easy to put your own together.
Any potting mix needs three things:
Bulk + Drainage + Nutrients
You can vary each bit to create perfect mixes for your plants, but the basic formula stays the same, and a lot of off the shelf products tick boxes for you
The basic soil I use is pretty much whatever I can get hold of for a decent price, but I’m trying to go peat free for sustainability reasons.
Dalefoot Wool Compost holds water well, and is rich in nutrients, so is especially suited for moisture loving plants like ferns and calatheas – but can be adapted for all kinds of houseplants. It’s brilliantly sustainable, using wool and bracken by-products and is made here in the UK. It’s a little pricey, but worth it if you bundle items together, and can be used indoors and outdoors.
Coco coir is a good, somewhat sustainable alternative. Best of all it often comes in space-saving bricks, which expand in water – so ideal for anyone who has limited storage space. And it’s great for padding out pots if you’re potting up lots of plants at the same time. However it has no nutrient value so you’ll need to add something in (see below).
Generally you can look out for other pre-made potting mixes brands like Westland Houseplant Potting Mix which is cheap and cheerful, and is often stocked in B&Q. Or there are plenty of other brands available in garden centres and homeware stores. However the vast majority of these contain peat, which is a non renewable resource with big environmental impact – see more from Jane Perrone here.
Even products labelled as houseplant mixes usually need some additional drainage to make sure it doesn’t hold too much water.
Depending on the type of plant, I throw in some extra materials I have bought for drainage. It does feel a little like mixing up a recipe, but one that I’m never that strict about! Here is what I add to the soil depending on the type of plant:
Leafy foliage plants like peace lilies and tradescantia – a handful of pumice or perlite
Epiphytic and vining plants like monstera, philodendron and epripremnum – some orchid bark or clay chunks
Succulents – pumice, perlite and/or horticultural grit
Tangent: a layer of leca
When potting all plants, I usually add a layer of clay pebbles at the bottom of the inner plastic pot. I find this makes it slightly harder to kill plants through overwatering (hands up who’s made that mistake!).
The layer means that if any water drains through and sits in the outer pot, the plant’s roots aren’t sitting in the water. And any excess can be wicked back up over time, saturating the soil (a mini version of ‘bottom watering’). Read more on watering.
The final thing to remember is that plants need nutrients, ideally through organic compost material.
In the wild that would be replenished through dying plant material being composted and mixed into the soil by bacteria, worms and the like. Unfortunately most indoor environments don’t have this natural cycle, so we have to find a fix.
Any fresh potting soil such as the Dalefoot or Westland mixes above will have this natural goodness in it, though this will be exhausted within months.
After this point, during the summer growing months, you’ll need to fertilise your plants with a fertiliser of your choice.
The same goes for coco coir, which has little nutritional value, so should be mixed in with something with high nutrients to start with, like worm compost.
Where to get your ingredients
So there we have it, three things to think about when you’re potting up your plants: Bulk + Drainage + Nutrients
I’ve included a list of suggested suppliers below:
- Peat free soil is available from Dalefoot composts, Moorland Gold and other British companies
- Pre-made soil mixes for different plants in small bags can be bought from Soil Ninja online or the Rose Clover shop in Southsea (if you’re not in Portsmouth, why not ask your local houseplant shop if they’d consider supplying small bags of soil mix?)
- Pumice and orchid bark can be bought from Soil Ninja online
- Perlite is widely available in homeware stores and garden centres like Stewarts, B&Q and Wilko
- Leca clay pebbles are available from IKEA or are often stocked in garden centres like B&M
Onwards to repotting! ✋
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