Monstera Thai Constellation Ultimate Care Guide (and how not to kill them)
You can now get a Monstera Thai Constellation for less than half what they used to cost just months ago. Still a pretty penny though (currently around the $400 to $500 mark in NZ), so nothing to sneeze at to be sure. But this dramatic price drop has suddenly meant many of us have been lucky enough to tick this holy grail off our wish-list.
So when you've parted with the equivalent of about 100 coffees (I like to think of big spends in coffee numbers), you might be a bit curious what to do - and not to do - with your precious arrival so you don't kill your new variegated buddy.
Easy, but not easy peasy
The good news is Monstera Thai Constellation are surprisingly easy care with a few simple considerations. Well. Simple once you know them. It's also scarily easy to kill them with kindness, or what you think is the right thing to do, especially if you haven't owned a Monstera at all before.
And no, they aren't exactly the same care as your trusty green giant Monstera Deliciosa, but they're close. Less tolerant of drying out and slower growing. My big boy Monstera is called Frank (short for Frankenstein - Monstera, Monster, Frankenstein? You get it). So if you have your own Frank you've kept happy, you're way ahead already.
Unlike the more sectoral variegation (a fancy way of saying 'big sections'), of the Albo Borsigiana - the Thai Constellation is more speckled and flecked variegation, and thankfully, has stable variegation.
That means your Thai Constellation will keep that gorgeous variegation. Bonus?What one leaf does, won't change what the next leaf does (not so with the Albo). Your Thai will not revert to fully green leaves! Believe me, the Thai really wants to be variegated.
The Thai's variegation is also more a creamy, yellowy-white than the Albo's pure bright white, so does have a definite creamy-yellow tinge to the white. More light helps it whiten and older leaves can lighten up over time too.
I've also seen some very yellow Thai Monstera pics, like this from Costa Farm's announcement that they will have Thai Constellation in 2022 (announcement here on IG which originally said 2021, but in the comments Costa said it's been delayed).
You absolutely can still get those lovely big sectoral patches on a Thai, like the Albo. Plus just because your Thai arrived with no big variegated patches does not mean it won't get them, as the variegation is in the cells, not dependent on the stem like the Albo.
I've found baby Thai leaves are more freckled and speckled, and as the leaves mature you get larger, cleaner areas of variegation and more 'spread out' less dominant speckling, but I don't have enough experience myself with multiples of them to determine if that's the case with all of them.
Light, light, light. Not sunlight. I'm talking light, free-draining soil. Do not make the mistake of planting your Thai in straight potting mix. That's a big no no. Way too dense. Talk about how to invite root rot!
Don't get caught up in the exact mix, but keep about a 70/30 ratio in mind. About 30% potting mix, and 70% free-draining for the rest. For the free-draining portion, think orchid mix, succulent mix, bark, perlite. I'm a fan of hydromix. Something like those, or a mix of them. You get the idea.
Oh, and don't fall for the myth of adding a 'drainage layer' to the bottom of the pot below the soil. I used to do that too. Turns out it actually increases water-retention, moving the water layer up closer to the roots! Who knew? You want free-draining right the way down and to use potting mesh at the bottom instead to stop soil loss when you water (more about the drainage layer and other plant myths here).
When it comes time to repot, don't. Just kidding. Repot if you really have to, but don't go overboard. And don't repot your new arrival too soon either! Rookie mistake I think we've all made. Let the poor stressed chap adjust for a while before putting it through transplant stress, on top of transport stress (I'd wait at about a month unless there's a health reason for a repot).
One reason I would repot is poor soil. If your Thai's not in suitable soil, or you spot slow release fertiliser in the mix, I'd consider repotting pretty soon, once he's settled in a couple of weeks, sooner if it's impacting his health. You don't have to pot up a size, just get rid of that soil and give him a better mix more suited to aroids, back in to the same pot if you like.
When you do pot up, only go up about a couple of cms (so from a 14cm to a 16cm for example). Too massive an increase can (at best) stop or slow stem and leaf growth while your plant diverts its energy in to root growth to fill up all that new room, or (much, much worse) lead to root rot from that big increase in soil holding far more water than the roots are used to coping with.
Back. Away. From. The. Water.
The Monstera Thai Constellation is 100% NOT the plant for you if you're an over-waterer. No helicopter parenting needed here. Time to change your watering ways. Think lightly moist, not wet.
Over-watering is far worse than under-watering for the Thai. Root rot is your enemy (and unfortunately Thai seem overly prone to it). BUT they aren't as tolerant of drying out like their green Monstera Deliciosa cousins either, so you need to find the right balance.
I'd wait till the top 5cms to quarter or so of the soil is dry before watering again. Don't let them fully dry out. If you're worried, a cheap water meter helps with peace of mind as you can push the probes down to check below the surface easily, but if budget allows, I'd seriously consider grabbing a Sustee. I've just started using them in my wish-list plants. Total game changer. A cheap investment for not stuffing up such an important element of care for these chaps.
Water hack: Get fishy
I personally use a mix of warm, nitrogen-rich water from my tropical fish tank, mixed with water straight from the tap, but I know some suggest avoiding tap water altogether for variegated plants, blaming it for browning edges and tips.
You could use distilled water, bottled water, rainwater, or just 'sit' your tap water overnight to help a some chemicals like chlorine evaporate. A trick I learned when you only have tap water available, is to add a few drops of AquaPlus (a fish tank product that takes chemicals out of water to instantly make tap water safe for fish).
I'm lucky to have a tropical fish tank. If you know of the YouTuber Kaylee Ellen, fish tank water is her go-to from her tropical tank for her plants at home too, but that's a plant hack I learned years ago from my lovely mum.
The right pot
You could go for terracotta depending on how diligent you are at watering. If you err on the side of neglect and are more of an under-waterer, stay away from terracotta as your plants will dry out too fast. Terracotta is a goodie for over-waterers though!
Personally I go for stock-standard, plastic nursery pots with drainage holes, popped neatly in a cover pot. I never water while in the cover pot, but you can. If you do, set a timer and tip out excess water after 10 to 15 minutes. Don't let your Thai sit or soak in water for long.
Thai have a deep root system, so a deeper / taller pot is a better choice than a wider / shallower pot for these guys. Whatever you choose, something with drainage holes is an absolute MUST for your Thai.
Although they can tolerate cooler and warmer temperatures short-term, aim to keep your Monstera Thai Constellation in his happy range of 20 to 30 degrees. They can tolerate cooler than 20 provided all other conditions are good and it's not a sudden temp change, but still best avoided.
Luckily that's a temperature range that's not too difficult to achieve in most kiwi homes, but do keep an eye on those temperature drops come winter, especially if you got your Thai during easier-care summer months. Vents and draughts are a no for these chaps. Sudden temp changes are also a no. Move them from the path of cool or hot airflow from your aircon or heat pump. Also consider what temperature your Thai's environment is when you're not home, and overnight.
Light is another area the Monstera Thai Constellation differs from her green Monstera Deliciosa buddy.
The more white variegation, the harder any plant needs to work to photosynthesize. Yep, that rather important 'vital for life' requirement. Since light is a biggie for photosynthesis, your Thai needs more of it than the all-green Monstera. Go for a position with plenty of bright light. Remember those white sections lack chlorophyll (otherwise they would be green), which means they can't absorb light. Low light is not recommended. Better to go for medium to bright.
Ideally that light should not be only from one direction though, as like her green cousin, she'll reach for the light and can become more leggy and less leafy. If you can't help the stronger light from one direction, quarter turn your Thai about monthly and she should be sweet.
With the main difference being that those white portions cannot absorb light, it means your Thai needs to work twice as hard as a Monstera Deliciosa to photosynthesize. Like any variegated plant, keep your Thai Monstera in bright ambient light. The brighter the better (within reason, dry, crispy edges and tips could mean you need to back off a bit).
Unlike some highly-variegated plants though, the Thai can handle some direct sunlight. Especially the greener more speckled and freckled leaves without big white patches. Those big white patches though? I'd keep clear of direct sun for fear of sunburn. Dappled, moving light is always better.
Stay clear of direct sun all together if unsure, but if the perfect spot for your Thai gets early morning sun in summer, or weaker daytime sun in winter, you should be fine. Just stay out of the sun for longer lengths of time, and no super-harsh daytime and afternoon sun direct in summer. Think gentle sun and you'll be sweet.
Monstera Thai Constellation have similar humidity requirements to their green Monstera Deliciosa fam. I'd call them 'medium' on the humidity scale. In a typical kiwi summer no extra humidity should be needed unless you like in a very dry region. It's plenty humid for our lucky tropical indoor plants in general in NZ.
In winter though - or if you have a heat pump running - or have a DVS or HRV system, or fireplace (anything that dries out the air) - best to consider running a humidifier. Look out for for crispy, dry, brown tips or edges as a sign extra humidity is required. For humidity I find a pebble tray doesn't do much, nor does misting.
The humidifier I use is one of the bigger H2O cordless ones. They hold a decent amount of water to run all day depending on the setting, the output is adjustable, and being cordless you can use them anywhere.
Tip for new arrivals: Thai Monstera typically start out in a lab environment if grown from tissue culture, then often moved to an indoor nursery with plenty of warmth and humidity, so they become used to a higher humidity environment. When you first get yours home, maintaining that warmth and higher humidity, at least for the first couple of weeks, will help your Thai settle in sooner with less stress, so less chance of disease or leaf loss - or those dreaded brown patches!
Being a slower grower than the all-green Monstera Deliciosa, the Thai rates at the lighter end of a medium to light feeder. However that doesn't mean you should starve them! Definitely do feed your Thai, just go easy. You don't want to risk fertiliser burn for the Thai even more than most.
You want a higher-nitrogen ratio food, which focuses your plant's energy on foliage (fertiliser for flowering plants tends to be lower-nitrogen, higher-phosphorus).
I'd also give anything with urea in it a big fat miss. Urea really shouldn't be in indoor plant food in my books, as being stuck in a container, excess urea can't leach away from their precious roots.
So no urea, and something complete and balanced with an NPK ratio focused on foliage. Excess minerals can otherwise build up and cause fertiliser burn. A sign of mineral salts build-up is white deposits on the top of the soil and underneath around the drainage holes.
The other thing a good food should include is calcium. It's one of the 16 essential nutrients plants need, but a lot of indoor foods lack calcium. Your Thai needs it to support big, strong leaves and strong stems.
Calcium's tricky too as it can't move around your plant like Nitrogen can, meaning a calcium deficiency in the soil when a new leaf is forming, is a deficiency for the life of that leaf (calcium deficiency can show up as smaller, stunted leaves, and deformed or curled leaves).
If the food you pick meets those needs, you're good to go. My pick of the many available is Foliage Pro which is the foliage formula made by Dyna-Gro. It's urea free. It does include calcium. It is a higher-nitrogen ratio. It's complete and balanced. Plus it's also a liquid concentrate, so easier to adjust the dose for lighter feeders (I feed 1ml per 3 litres for all my lighter feeders like my TC, and 1ml per 1.5 litres for everyone else).
What I would say, no matter what food you choose, is best not to go overboard on the DIY fertiliser. How well your Thai will grow depends on what nutrient it has the least of, not the most. Not enough of a micro-nutrient can lead to excess of a macro-nutrient. It's too easy to overdose on one nutrient when you make your own.
By all means experiment on your cheaper jungle members, and your Thai if you really want to, but for me the price tag on a Monstera Thai Constellation puts it firmly on my non-guinea-pig list. No banana skins, eggshells, milk-watering, tea, coffee grounds... (the list goes on).
Monstera Thai Constellation Pro Tips & Problem Solving
Translucent changing to brown patches, only on highly-variegated or white areas
Something like this:
This one can be a bit upsetting as it may mean you'll lose that leaf, depending how bad the browning is, and how fast it gets worse. The upside is it's unusual to lose the whole plant. You may however lose more than one leaf before it comes right.
When your Thai has a lot of highly-variegated leaves (big white sections or a mainly or all-white leaf), it simply cannot photosynthesize well enough to survive as long as greener leaves. Those leaves with big white sections are weaker. They are more delicate, more sensitive, and age faster, so turn brown and die off faster - especially when under stress (such as the move from a warm, humid nursery, to your home). A balance of at least 50/50 green to variegation is a healthier minimum for a leaf to be stable.
When a leaf starts browning like this, you can try cutting off the brown patch (not the green!), or the entire leaf, or leave it as is and hope it doesn't spread. Either way, what you do want to do is make sure conditions are good in general, check that it's not fungal or from overwatering, and that you're not contributing to your plant's stress levels.
This is unfortunately pretty common when you first take any super-variegated plant home, or get it delivered. Remember before it got to you, it likely left its cozy home in the nursery where it has been for some time (often in warm, humid, bright conditions), then got transported to the plant store - and if the store doesn't quarantine - wisked away again, shipped off to you before it can even recover after the trip from the nursery! This is a common concern with other extra-variegated plants like Super White Marble Queen also.
If your Monstera's already under stress, then you do something silly like promptly repot him, you've added transplant stress, on top of transport stress. Ouch. Big time changes for any plant, let alone those weaker extra-variegated leaves. Keep in mind repotting to a plant, is like surgery to us. Big time recovery needed.
What you can do to help, is find one, perfect spot, and leave him to settle in. Don't water too soon. Feed, but not full strength when you do water. No direct sun. No draughts. Trim off those brown patches if you're feeling brave. Wait and hope (and try not to worry!). Hopefully those lovely new leaves that will eventually replace any leaves lost, won't be so white. And if they are, won't brown early.
If your plant's had no recent stress, no change in environment, and it's starting to brown in patches, also check over-watering, fungal disease, pests, sunburn or heat stress.
Leaves turning yellow
Many things can cause yellowing leaves. You'll likely know which the cause is from this list as you can check your plants conditions and care in person. Firstly, check you're not overwatering. Yellowing can be the first sign you've overwatered. Also check your Thai is not rootbound. They generally need repotting up a size about every 2 years.
Yellowing or wilting leaves combined with dying stems can be due to root rot, which Thai Monstera seem more prone to than other cultivars. If you suspect root rot, act on it immediately. Do not wait to see if it gets worse. More about what to do to treat root rot coming up below.
Yellowing older leaves can just be due to old age, but Monstera tend to not to lose older leaves like other faster growers do, so yellowing older leaves may instead be due to a Nitrogen deficiency. Start feeding, if you don't already, and pick a food that is complete, balanced, and free of urea to avoid fertiliser burn. Nitrogen is a mobile nutrient. If your soil is deficient, your plant will steal nitrogen from older leaves and redirect it to newer leaves, leaving older leaves yellow.
Brown crispy edges
In Monstera this is typically due to either light or humidity, or food and water. Increase light levels if you suspect that's the cause. Increase humidity if your air at home is dry. Try using water without chlorine, or treat your water with a product like AquaPlus to instantly remove chlorine.
Lastly but very importantly, check what you're feeding. Avoid food that is not complete and balanced so that excess mineral salts don't build up in the soil and burn roots and leaves, and also check your food is free of urea, which can also cause fertiliser burn in indoor, potted plants.
If you notice signs of mineral salt build-up (white deposits on the soil surface or around drainage holes under your pot), then gently flush the soil with water by running the tap in at the same rate water drains out. If that's not realistic, pour a decent amount of water through a few times and let it drain well.
You can trim off the brown edges if it's only the very edge as I find it hardens up again, but if it's a bigger section I wouldn't trim entire chunks off as you may end up losing the entire leaf. Up to you based on how bad it is and if it's spreading or not.
The Thai can pop out a new leaf every month when it's really humming, or be the snail of the plant world with slow or sometimes no growth. It's not unusual to hear complaints about no growth for months after they move to their new home. Some love life and get growing again pretty fast, but in general a 3 to 6 month 'nothing to see here' hiatus is pretty normal, especially if they move home in cooler months.
Other possible causes of a growth slow-down are not enough light, cooler temperatures and nutrient deficiencies - but if your Thai is otherwise happy and healthy and conditions are good, he's not in too giant a pot, you're feeding (but just lightly), then have patience. You should get new growth when the time is right. Higher humidity can help speed up growth also.
If the whole leaf is going brown one common cause is not enough water. Check the soil. Give him a water if needed. And keep to more consistent watering going forward. Also check the other problems above and below. If only the edges are going brown, dry or crispy, it could be too much light, or fertiliser burn.
Thai Monstera are particular prone to root rot. Usually caused by overwatering. Too much water, leaves not enough oxygen for roots to breathe. Dense soil can also hold too much water, causing the same problem even when you don't overwater. Free-draining soil is a must.
Roots affected by root rot will be black and mushy. Leaves will typically be limp, wilt and go yellow. Slide your Monstera out of the pot and check the roots. It can quickly spread to infect healthy roots too, so don't delay. Deal with root rot immediately. Treating root rot as soon as possible is essential for your plant's survival.
Sometimes a fungus can be dormant in the soil and cause root rot but it's more likely to be overwatering. Either way, remove your plant from the soil and wash the roots under running water. Using clean, sharp snips, prune off damaged roots. Dispose of the soil and clean the pot (a mild bleach solution will kill any fungus in case that's the cause). Put fresh, well-draining soil in and repot in the same pot (or same size pot).
But wait, there's (probably) more...
If you have issues with your Monstera Thai Constellation that I haven't covered, by all means message me and let me know - ideally with photos - and I'll add to the guide so your experience benefits others.
Phew! That's it (for now)
This care guide just kept getting more and more 'ultimate' and further away from going live every time I thought of new tips and tricks. I've drawn a line in the sand, and hit 'go live' but no doubt will keep on adding to this over time.
If this article helped you, please consider a share. There's no income from it for me, I just really like to know it might help one more person enjoy their happy, healthy Monstera Thai Constellation :)