Soil Mistakes - Don't Choose the wrong dirt!
When starting out in this hobby, it’s easy to feel overwhelmed by all the options, different advice and guesswork involved in caring for houseplants. Here at Soil.Ninja, we’ve always loved sharing what we’ve learnt and helping to make this hobby as easy as possible. The more you learn, the fewer mistakes you make, and the more plants you can keep from kicking the bucket.
Although losing a few houseplants along the way whilst you’re learning is completely normal - We’d love to help you avoid some of those common mistakes. We’ve lost plants along the way, too, and we wish we’d had an educational resource to turn to that could have helped us save some of the plants we once loved. RIP to all of our OG Alocasias in particular.
So let’s talk about those soil mix mistakes…
Garden Compost
Using garden compost is a common mistake many of us make when starting out in the hobby. You’ve got some leftover outdoor soil in the shed and a new plant to pot up – seems pretty straightforward, right? Not so fast! We wouldn’t recommend using garden compost as a soil mix for your indoor plants!
Garden/outdoor compost aren’t designed for growing tropical houseplants indoors. They will compact over time, restricting airflow around the roots, and may even introduce pests, pathogens and diseases.
Garden compost lacks the structure and aeration needed for indoor growing, meaning it will retain moisture for much longer than your plants need. This can leave roots sitting in overly wet conditions, increasing the risk of root rot.
It also has the potential for a build-up of soluble salts and excess nutrients. Outdoors, rainfall helps flush these through the soil over time, whereas indoor plants rely on us for watering and have limited opportunities for these substances to leach away. This can lead to salt accumulation, which may cause root burn.
Overall, garden compost isn’t our recommended choice for a soil mix for your indoor tropical plants, and we wouldn’t recommend trying to amend it either – there are better options!
Outdoor Clay Compost
The negative side of outdoor clay compost is similar to typical garden compost, which we discussed previously. However, clay compost will compact more quickly, restricting airflow around the roots and increasing the risk of root suffocation and root rot.
Once the clay eventually dries out, it will shrink, compact and pull away from the edges of the pot. When you go to water your plant again, water will run down the gaps between the compost and the pot rather than soaking into the whole soil system. This means the roots may not receive the moisture they need, even when you’re watering regularly.
Clay compost also carries the risk of introducing pests, pathogens, harmful bacteria and diseases into your indoor growing environment. For these reasons, we’d strongly recommend avoiding outdoor clay compost in your indoor plant pots.
Straight from the Ground
A free option sounds pretty good, right? But I hate to say it, my friend, it’s not one we’d recommend. Sorry to be a negative Nelly! Soil dug straight from the ground outside your home isn’t something your tropical houseplants will be too keen on.
The quality and composition of outdoor soil across the UK vary massively depending on where you live. Different regions have different soil types, each with their own properties, so you never quite know what you’re digging up and putting into your plant pots.
Garden soil taken straight from the ground will offer poor drainage and aeration, compact over time and introduce unwanted pests, pathogens and other nasties. It simply isn’t designed to provide the conditions tropical houseplants need to thrive within your home.
The one benefit we have to be honest about? You might find an earthworm or two! And here at Soil.Ninja, we bloody love worms and their poops. But you can get those benefits much more easily by adding worm castings to a suitable soil mix, without bringing all the potential downsides of outdoor soil into your home.
Big Box Store Soil Mixes
We’ve spoken about this a few times, and if you’re familiar with our small business, you’ll know we like to mix our substrates to order. This helps us provide fresh mixes containing components and amendments to support healthy root growth, aeration and drainage.
However, when it comes to big box brands, their soil mixes are often produced well in advance and may sit outdoors for extended periods. The bags tend to have tiny holes that provide an opportunity for unwanted visitors, such as fungus gnats, to find their way inside.
Some cheaper mixes may also lack the range of amendments and nutrients your tropical houseplants need to thrive. Depending on the product, you may find larger amounts of low-cost organic materials, such as wood chips, which can temporarily tie up nitrogen as they decompose. This can affect nutrient availability and potentially contribute to plant health issues. It's also worth checking the pH, as some mixes may be too acidic for more sensitive plants.
These mixes won’t necessarily kill your plants; however, the quality, consistency and suitability of the ingredients can vary considerably.
Our advice? Always do your research, check the ingredients and choose a substrate you feel confident using. Your plants will thank you for it!
Peat Moss
We love peat moss, but only when it stays where it belongs! Peatlands are incredibly important natural habitats, supporting wildlife, plants and entire ecosystems. Harvesting peat damages these habitats and releases carbon that would otherwise remain stored in the ground. Thankfully, there are alternatives that allow us to grow happy, healthy plants without relying on peat.
Carnivorous plants are a little different. We're still exploring the best peat-free alternatives for these sensitive plants, as they can struggle in other growing mediums, including coco coir, due to factors such as salt content. However, many tropical houseplants grow perfectly well in a coco coir-based mix, with the right amendments, so peat moss isn't necessary.
Peat moss also has its downsides when it comes to growing houseplants. It's naturally low in nutrients, can become hydrophobic (repelling water when it dries out), and may compact over time, reducing airflow and oxygen around the roots. It's also acidic, which suits some plants but isn't ideal for every species.
Commercial and greenhouse growers often rely on it because it provides consistent growing conditions that help plants grow quickly and predictably, ready for sale. But what works best for large-scale production isn't necessarily the only, or most sustainable, option for growing plants at home.
We'd also encourage you to look beyond the labels. Some brands use “peat-free” claims that can be misleading, relying on greenwashing tactics rather than offering genuine transparency about their ingredients. It's worth checking what's actually in your growing medium, rather than taking the label at face value.
Standalone Coco Coir
We wouldn’t necessarily call coco coir a mistake, as it’s a fantastic base for houseplants and has plenty of benefits! If you’re new to the hobby, using it as a standalone growing medium can do a decent job, depending on your home environment, watering habits and the plants you’re growing.
However, elevating coco coir with amendments such as perlite, pumice, bark or lava rock can make your mix more reliable and forgiving. These additions can help improve aeration, drainage and structure, giving your plants a little more breathing room if you accidentally water too soon or your home is cooler than ideal, causing the medium to hold onto moisture for longer.
Soil Ninja Soil Mixes
Okay, so we might be a little biased, but using Soil.Ninja is far from a soil mix mistake. In fact, it might just be one of the best choices you can make! ;)
All our mixes are formulated with your plants in mind, as well as the conditions we have in our homes. We want our blends to be forgiving, giving you a little more wiggle room as you learn. Honestly, we wish we’d had these mixes at the start of our plant journeys, but Soil.Ninja is really the result of everything we’ve learnt along the way.
Our blends bring together nutrients, bioactivity, aeration amendments and suitable pH levels to help create a growing environment your plants can thrive in.
And we don't just leave you with a bag of soil and wish you luck! Our mixes come with plenty of helpful information, and our website is packed with blogs and growing advice to guide you along the way.
So, if you feel like you've made a mistake with your potting medium, don't panic! It's completely normal to experiment, adapt and change how you grow as you learn more about this beautiful hobby. And if you ever have questions, we're always just a message away!