As I was doing a bit of last-minute repotting over the weekend before Autumn properly sets in, I thought I would turn the camera away from my plants for a minute + chat a little bit about the potting mix I tend to make up for my houseplants, because it’s a question I get asked a lot! This is intended to be a shorter + more snappy post than my longer form plant care content. It will address the topic of soil mix which I know can sometimes be a little intimidating if you are new to houseplants.
At this time of year, a heavy soil mix, lower levels of light + colder weather can be a headache-inducing combination, especially if you are a bit heavy handed with the watering can. If you want to read in more detail about cold weather plant care, then here’s the link. In terms of soil, if your potting mix is too heavy, root rot can become a very real problem because the compost will be taking too long to dry out. A very dense mix can prevent the roots getting enough oxygen which can put them under considerable stress + cause them to rot. If the roots rot, your plant will start to deteriorate + unless caught early enough, the plant will die. I prefer to keep the majority of my houseplants in a free-draining potting mix year round because I’ve figured out a tailored blend of compost + soil amendments that have been keeping my plants not just happy but thriving too.
I have a general houseplant potting mix that I make up when I’m doing a repotting session which I can tweak + adapt to suit the plants that are on my potting table. I generally try to re-pot plants with similar needs at the same time (but only when they need it!). If you were wondering about the mix I use for specific plants, have a look through my repotting diaries posts; I address some of the particular plant needs in these posts — they are all linked here!
At HPH, I like to keep a stash of a few failsafe components that I know work well. These are all items I have sold in my shop + I know my customers like too. My potting mix + soil amendments kit consists of:
- Houseplant focus compost by Growth technology (I get the peat-free version)
- Orchid bark
- Horticultural grit (or pumice if I can get hold of it – grit is easier to find)
Some ‘extras’ I have for specific tasks (or plants) include:
- sphagnum moss
- chunky coco coir
- activated charcoal (carbon)
- worm castings
- cacti + succulent potting mix
It’s true that these things are perhaps the ‘boring’ purchases that are often the unseen elements of houseplant care — potting mix is not pretty like plants… but it is a necessity! Before you splurge all your cash on plants, I really would recommend making sure you have some quality ‘potting arsenal’. Even if you have to pass on buying plants for a month or two, it will be worth it + your plants will thank you! In suitable mix, they will cause you much less stress in the long-term + it can make a big difference to their health + growth. PS. If you are going to the nursery for these items, consider making a bee-line for them before getting distracted by plants!
If I was to suggest 3 purchases as a ‘starter kit’ I would recommend a bag of houseplant compost, orchid bark + some perlite. You can build up some of the other items over time as you need them. Store everything in a cool dry place.
For most of my houseplants, it looks a little something like in the photo below. I don’t measure anything out + find it better to work by eye, but for reference, I’ll start with something like equal parts houseplant potting mix + orchid bark + perlite with a half measure of pumice for that part. The photo above with the component parts laid out on white is reflective of the approximately the ratio I use, with less or more pumice depending on the specific plant in question.
Finally, to go back to the issue of watering, if you have been used to heavier compost + this is the first time using a mix like this you will notice that you will probably need to alter your watering habits. As this is a lighter + more airy mix, the water will run through + not sit on the surface which is much better for your houseplants. This also means the mix will dry out quicker, so bear this in mind.
The type of pots you use will also play a part in combination with your potting mix — terracotta dries out much quicker than other pots + pots without drainage can be hard to judge so I tend to avoid them, or drill my own hole. Most of my houseplants are in nursery pots inside cache pots + my succulents + cacti are usually in terracotta.
Be mindful that with the onset of cooler temperatures, your watering routines will also need to adapt. To ensure you aren’t overwatering, you might consider using a moisture monitor/hygrometer, with your houseplants — especially if you tend to over water. Here’s the one I use, I got it a few years ago as a Christmas present + it’s still going strong:
With lower light levels + colder temperatures, some of your houseplants will stop growing + enter dormancy whereas other plants will just slow their growth right down. This means less watering + stopping feeding until Spring rolls around again. Lastly, as I said in my Autumn plant prep post, it’s a good idea to lay-off repotting over Autumn + Winter, unless any of your plants are really struggling. But if you have any last minute repotting to do, or you have any specific plants you want to get in some free-draining potting mix before Winter then I hope this post has been useful. You can refer back to this post at any time under the houseplant basics tab.
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