7 Indoor Houseplant Myths That Fooled Us Too
I've got my mythbusting hat on. Not the lame click-bait myths that aren't really myths - but real, honest-to-goodness plant myths I know someone, somewhere, believes in right now. Confession? There are a few I was guilty of falling for too...
Myth #1: Pots should have a layer of stones or bark to help with drainage
Nope! This is one we totally thought was legit for years. When potting, you always add a drainage layer to the bottom of the pot of gravel, bark, or pot shards, right? Wrong!
The bottom of the soil will naturally hold water, so when you add a layer below the soil, you just move that water layer up, closer to your plant's precious roots, which increases the risk of root rot. Don't take our word for it. It's science!
This myth got busted over 100 years ago (we didn't get the memo), when some white-coated dudes demonstrated water doesn't move easily from fine layers to coarser layers, and soil has its own water level. So until the soil is totally saturated (that's a bad thing), gravitational water won't budge down.
Totally saturated water is root rot heaven, because saturated soil suffocates roots, leaving no room for oxygen. Studies since then also found a coarser layer below the soil, actually increases how much water the soil will retain! All sorts of 'no thank you very much' right there.
Drawing is from Garden Gate Magazine who covered the same myth here
What to do instead when potting plants
Keep that water layer away from your plant's roots. Fill the pot right to the bottom with soil. Just add one layer of something thin to stop soil washing out the drainage holes that still allows water to drain freely. We've used everything from a paper coffee filter to cheesecloth, but drainage mesh is even better. We've also tried chux cleaning cloths, folded newspaper, and even paper kitchen towels at a pinch although they're not as free draining as proper drainage mesh.
PS: Apply the same thinking to mixing your soil when repotting. If using bark, succulent mix, perlite or similar to create a lighter, free-draining mix, don't put it all at the bottom of the pot. Mix it in well with your potting soil to create a consistent mix throughout.
Myth #2: Bathrooms are great for plants
Actually, bathrooms can be a pretty miserable place to hang out if you're a plant. Sure, mid rubber-duckie bath, or while you're having that long, hot shower ignoring the power bill - up goes the humidity. Lovely.
But for how long? What about after you're dry and out of there, leaving your precious plants behind? Bathroom surfaces are made to drain and dry fast. Plus the bathroom can often be the coldest room in many houses. Colder air retains less humidity. Dry and cold? Not so appealing for a heat and humidity loving plant after all. Instead, consider the conditions your plant is in for majority of the day, not just 10 minutes.
What to consider instead when picking locations
An average, overall warmer air temperature in a room is more beneficial to most plants, than a temporary boost in humidity. Warm air contains more moisture. If you have a drier home, run an HRV or DVS system, run air con or a heat pump, consider investing in a humidifier instead if low humidity is a concern.
If your bathroom meets your plant's needs most of the day - not just when you're in the shower - then go for it, otherwise maybe give it a miss.
Myth #3: Misting increases humidity
We wish this was true, because misting is such an enjoyable part of owning plants, but if the only reason you're misting your plants is to increase humidity, you're not going to like this news.
It's true that misting - at least twice a day mind you - may slightly increase humidity, but by so little that your plants will barely register the difference. Misting does however keep leaves clean - important so they can absorb light and 'breathe' more easily - and you can use your mister to foliage feed too. So go ahead, keep on misting to your heart's content if it makes you happy. There certainly is benefit to your plants too - just not in the way you might think.
What to do instead for humidity
If you're worried your humidity level is too low, get a humidifier! Second best if a humidfier is out of budget, is bunching plants together and adding a pebble tray, with the water level in the tray kept low enough not to cause wet feet for your plants. Although both those don't make a huge difference like a humidifier does, they still help.
But if you're seeing signs like brown tips or dry crispy leaf edges - even though the soil moisture is fine - then that's a sign your plants might need an upgrade to a humidifier. I love the cordless H2O humidifiers range for my jungle, and also own one of those bigger Crane humidifiers (I got mine from Mighty Ape).
Myth #4: Plants grow bigger in bigger pots
Ah, nope. If you want bigger plants, most will get biggest when kept slightly rootbound. When repotting, only go up one or two pot sizes (from a 14cm to a 15cm pot for example).
Jump up too much in pot size and two things can happen. The first is the sudden increase in extra soil around the roots can cause root rot, as the soil retains a suddenly increased amount of water that your plant isn't used to. The second is your plant diverts its energy in to growing new roots to fill out the too-much bigger pot, instead of putting oomph in to growing leaves, and growth slows or stops.
What to do when moving up a pot size
Only upgrade by 1cm to 2cms in pot diameter. From a 14cm to a 15cm or 16cm pot for example. Perfect. Also, don't repot too soon. Being a bit rootbound is not a bad thing for many plants.
Don't judge when a plant is rootbound only by roots coming out the bottom. Always slide him out and check the entire root ball rather than risk repotting before a plant really needs it. Repotting puts a lot of stress on a plant - think of it like us going through surgery - and risks root rot.
Myth #5: Don't feed plants in winter
You hear a lot of talk about plants going 'dormant' in winter. That's outdoor garden talk. Most of our indoor houseplants come from tropical regions that are warm outdoors, all year round, and don't go dormant. However just because our jungle goes through cooler months than they might prefer, doesn't mean they go into hibernation, especially when kept indoors.
Instead, growth slows over cooler months. It doesn't stop. Most plants do not 'switch off' over winter or need a 'rest'. It is true that you should not feed a plant that isn't growing at all. You don't want to risk fertiliser burn from nutrients building up in the soil instead of being used by the plant (if you're worried about that, checking your fertiliser is free of urea will help).
Unless you know your plant is actually dormant - or a type that requires a 'rest' - it's important to keep up the plant food BUT simply adjust it for your plant's growth needs.
How to feed in cooler months
In spring and summer, I feed my jungle about once a week to once a fortnight. When it comes to autumn I halve that to about once every 3 to 4 weeks. Because you water less, you naturally feed less in winter, without having to change the dose. I only skip feeding in winter for plants that have genuinely gone dormant, otherwise everyone gets a feed about once a month in winter. No way I want deficiencies to develop over winter and impact that lovely spring and summer growth.
Myth #6: Plants can survive with no light
All plants need some light. If the natural light level is so low you can't easily read without flicking the light switch on, then give it a miss for plants too. Yes, there are plants that will tolerate lower light levels, but tolerate does not mean thrive!
What plants can you put in low light areas?
I'd go for a trusty ZZ plant (like this dude far right below), Peace Lily, Aspidistra 'Cast Iron Plant' or Sansevieria, but even then - if it's really low light - swap their location around at least monthly to give them a break to recharge in a brighter area.
Myth #7: Sick plants need fertiliser
When you feel a cold coming on, a lot of us reach for the vitamins. This same thinking is behind why we grab fertiliser for a sick plant, stat. In fact, we've all got our thinking backwards on this one.
A healthy plant that's busy growing, not dying, is the chap that needs the extra food. Sick plants absorb less nutrients from the soil than healthy plants. Adding fertiliser to an already sick plant might just push him over the edge by causing fertiliser burn, burning tender roots and causing leaf damage.
Fix the cause of what's causing your plant to be unwell, and save your fertiliser for your healthy, growing plants that are busy depleting the nutrients in their soil. I'd definitely consider a dose of protective silicon though (Dyna-Gro Pro-TeKt is a goodie to help sickies).
So there we go. A round-up of 7 planty myths I reckon someone, somewhere believes right now. Well, I hope they do anyway - because it makes me feel better for the ones that caught me out too ;)