How to Water Houseplants: The Ultimate Guide

Getting to grips with how to water my plants was life-changing when it came to my ability to keep them alive for more than a week. Now they actually GROW.

I oscillated wildly between being an extremely neglectful plant parent to being a chronic over waterer, and let me tell you: your plants won’t thank you for either of those things and definitely not both.

So, to my Monstera Deliciosa, Dracaena Margintata Tricolor, Yucca, and spider plant: thank you.

You’ve put up with a lot. I promise I’ve changed.

Watering was something that seemed so fundamental, and whilst it’s not exactly rocket science, my preconceptions of what plants require took a lot of overriding.

I assumed that watering every day was best practice, which I’d keep up for a fortnight and then completely forget about my plants for months. And then repeat the cycle.

That’s probably the third worst thing you can do to your plant, watering wise, after watering them every day until they die and never ever watering them.

This is a monster of a post btw. If you cba, watch the video.

Basically, it’s as simple as watering them when they’re thirsty, and not watering when they’re not. You know, like how you water yourself.

Too little water and you’ll dehydrate and eventually die.

Too much water and you’ll drown, pretty sharpish.

It’s the same with plants. 

And, like humans, it’s not as simple as setting a reminder to have a drink daily or weekly or whatever.

Many different factors influence how much water we (and plants) need. Check your soil before blindly adding water.

ok, let’s dive in.

When to water your houseplants

Water your plants when the soil is nearly dry.

Sure, there are certain plants that like to stay consistently damp, and others that like to stay dry, but most will be happy if you water them when the soil is almost dry.

I use a moisture meter to tell when to water. They’re not 100% accurate but they work for me.

In summer, I check my plant’s soil every week.

• First, I pick up the plant.

If it feels light, it probably needs watering. Water is heavy, so the difference between a thirsty plant and a hydrated one is quite significant.

It won’t take long for you to be able to tell if your plant needs water just by it’s weight.

I keep the majority of my plants in plastic nursery pots because they’re very light, so I can tell more accurately how heavy the plant is.

• Then I use my moisture meter

I check the reading, and using the information I have, decide whether or not to water. If the moisture meter reads 3 or under I water. If it reads 4 or above, I don’t.

Sometimes the pot is light but the moisture meter claims the soil is wet. In this case, I stick my finger in the pot to check. Often if the soil mix is chunky the moisture meter can’t get an accurate reading.

Trust that you know what wet feels like.

Technically humans can't determine whether something's wet or dry by touch alone but we're pretty good at determining it by other factors like temperature and, er, how much soil is sticking to our finger when we take it out of the pot.

How do I tell if my plants need watering?

The most important thing to remember is that you need to check the soil NOT the plant. If your plant is showing signs of dehydration, you’ve waited too long.

Now, waiting for plants to show signs of dehydration won’t necessarily kill them (though it could over time) BUT it weakens them and can cause them to send out stress hormones. Stress hormones attract pests.

Stressed plants also don’t grow as well or as quickly as unstressed ones, so stop looking to your plants for signs of dehydration. Check the soil. When it’s dry, water it.

A good rule of thumb is to water your plants when the top inch or so of the soil is dry. Put your finger in and test it. Moist soil will stick to your fingers more readily than dry soil.

You also need to check further down in the soil – especially if your pot doesn’t have drainage holes.

Here are some signs that your plants need watering

Bear in mind that plants only have a certain number of symptoms. A wilting plant is just as likely to be overwatered as it is underwatered.

I know it’s annoying, but it’s the way things are. I have an article on how to decide if something is over or underwatered here, but if the soil’s dry you’re probs underwatering and vice versa.

• The leaves/leaf tips have gone brown

Basically, the leaf cells have died due to lack of water. There’s no way to restore them, so chop off the brown bits and try to get there quicker next time.

You’ve left it too long if this happens.

• Wilting

A classic. The leaves will droop and look very sad and sorry for themselves. Some plants (Marble Queen pothos, I’m looking at you) are extremely dramatic about this, going from fully upright to on the floor in half an hour. Luckily, a good drink will quickly restore them. Just be sure that it’s definitely dehydration that’s causing the wilting.

Syngoniums, peace lilies and fittonia are all droopers.

• Wrinkly leaves

Hoya and cacti tend to go a bit wrinkly when they’re thirsty. Like the wilting though, they recover quickly once they’ve had a drink. This is something you have to look for closely since often the backs of the leaves look more wrinkly than the front.

• Slow growth

If you’re not giving your plant enough water to thrive, but enough to survive, it won’t die, but you won’t get much new growth. If the plant does manage to produce new leaves they might be stunted and small, or the plant may have to cast off old leaves to accommodate the newbie.

• Dry soil

For plants that store water (like cacti, succulents, and plants with tubers), dry soil isn’t an issue – at least not until they deplete their own stores*. But for plants like ferns and Calathea, completely dry soil can lead to crispy leaf tips and dehydration.

I like to keep the very top of my soil dry to deter pests, so a moisture metre is invaluable to me for making sure the soil is adequately moistened.

*They still don’t like to sit in dry soil for a long time. Check them just as often as your other plants. If they’re kept in good conditions (i.e. as close to the sun as you can manage), they’ll need water pretty often.

• Weight

A light plant pot is a great indicator that it’s time to water. If you keep your plants in their nursery pots then you’ll be surprised how quickly you’ll learn how to tell when to water just by picking it up.

I have an article here on the 9 ways you can tell if a plant needs watering.

Factors that influence how frequently you need to be watering your houseplants

I’m afraid it’s not as easy as setting a weekly reminder to water your plants. You may have the odd plant that likes a drink once a week, every week forever, but that’s the exception, not the rule.

That being said, I do set a reminder to check to see if my plants need watering every week. If a plant says 4 on the moisture meter, I’m not diligent enough to check it the following day – it has to wait until next week.

And whilst it’s common sense that some plants by design need more water than others, there are many factors that can influence your plant’s watering schedule. Also, the plant’s conditions will influence how much water it goes through. A cactus kept in bright light might need watering just as often as Calathea in medium light.

• Time of year – when it’s warm and your plant is growing, it’ll use more water than when it’s cold and not growing (like in winter).

• Size of the plant – more plant need more water

• Size of the pot – the bigger the pot, the more water the potting mix can hold, which is probably why big plants don’t need watering very often but need lots of water when they do. Small pots will go through water more quickly. This is why baby plants need so much attention

• The material of the pot – plants in terracotta pots dry out more quickly than ceramic ones because terracotta is porous and the water can evaporate through the pot. Great for chronic over waterers.

• Lifecycle – if your plant is suddenly very thirsty all the time, check to see if it’s putting out a new leaf. If it is, check it daily – you don’t want the plant to compromise a leaf (sometimes the new one, often an old one) to save water. If you can’t see a leaf growing, check that’s it not root-bound.

• The type of plant – a general rule of thumb is that plants with big, thick, or waxy leaves will be able to store more water than a plant with little thin leaves (because water is stored in the leaves). This is why ZZ plants are so hardy – their leaves are so waxy they look fake. ZZ plants can also store water in their roots. Plants have evolved to adapt to their surroundings, just like we have.

How to water your houseplants

I’m going to go through all of the various ways of watering your plants. There is no correct way. It doesn’t matter if you go round with a watering can, sit them in the bath, or drag them all outside in the rain.

As long as water is getting in the soil, the plant does not care.

Top watering

Use a watering can or something with a spout – if you just use, say a jug, the water will come out too fast and blast through the soil and out of the drainage holes without being absorbed.

I use an old teapot. I fill a 5 litre water bottle with tap water, and use that to refill the teapot. In winter, I let the water come up to room temp, in summer I use it straight from the tap.

I sit the plant on top a oven shelf laid over a stock pot. I pour the water over the soil until the soil is thoroughly damp and water is running out of the drainage holes.

Technically you shouldn’t reuse the water that collects in the pot, but I do.

Pros of top watering:

• Convenient
• Flushes away salts and potentially pests
• Ensure the plant is thoroughly moistened (ew, what a phrase)

Cons of top watering:

• Can lead to soil compaction
• The surface of the soil is dampened and will draw the attention of fungus gnats. Every glass of wine you drink will now have to be shared with a fungus gnat
• Can damage leaves – some plants like African violets don’t like getting wet leaves (you can just dry them afterwards though)
• Can lead to water marks on the leaves – not a big deal, but read this post on how to get rid of them.

Bottom watering

Simply fill a vessel with water and sit your plants in it. You can use the bath if you have plants that aren’t averse to tapwater (or you have a filter unit for your bath), the sink, or a large tray. I use an old rabbit litter tray, but oil trays for cars or potting trays work well too.

I have a few terracotta pots with multiple cacti in that are too heavy to be lugging around. Instead of using saucers, I bought white pasta bowls from Wilko that they sit in. When I water them I just fill the saucer and leave them to it.

How long you leave your plant varies. A small pot may only need a few minutes, whereas I leave some of my larger pots for a few hours or more. As a general rule of thumb, once you see the top of the soil start to glisten, that’s long enough.

I personally don’t wait until the water has reached all the way to the top, because I don’t want to encourage fungus gnats. Instead, I use a moisture probe – when the probe reads as a 6-7 a couple of inches down I remove the plants

Pros of bottom watering:

• Doesn’t cause soil compaction
• Reduces pests
• Encourages stronger root systems

Cons of bottom watering:

• It can be a bit of hassle before you establish your routine, especially if you have big plants
• Doesn’t remove mineral deposits
• It can take a while

If you’re interested in learning more about the pros and cons of top and bottom watering, I wrote a more in depth article about it – click here to read it.

Equipment needed to water houseplants

Ok, you don’t NEED any specialist equipment to water your plants.

Seriously.

For all I care you can top and bottom water them simply by running them under the tap or sitting them in the sink. Job done.

I would recommend a couple of pieces of equipment though. I use an old teapot for a watering can, and the aforementioned bunny litter tray is indispensable (I use it to collect rainwater outside as well as a plant soaking station).

But I’d give either of those up in exchange for a moisture probe. Mine was instrumental in me finally learning how to make my plants grow. Before that they were just…not dying.

They’re not expensive – you can get one for under a tenner on Amazon. You simply stick the probe in the soil (I like to take a few readings) and if the probe says the soil is dry, water it. If the probe says the soil is moist or wet, leave it alone.

The actual probe bit is also useful for breaking up the soil to avoid compaction (which can lead to root rot).

You can get all kinds of automatic watering systems and misters and water filters etc, but my plants have been just fine without them.

Misters

Misting is a subject that massively segregates the plant community. I wrote an article about it here.

I would, however, recommend some spray bottles for things like bug spray and soap for cleaning your plants.

I have some nice amber ones on my resource page.

Types of water

Ok, so there are, believe it or not, four main types of water: tap, rain, filtered and distilled.

And that’s just the most common types – there are more.

Tap water

You know, the stuff that comes out of the tap.

Tap water is fine for most common house plants.

It’s often recommended that you leave your tap water out overnight to allow some of the chlorine to evaporate away and I’m not saying that some chlorine doesn’t go, but I am saying that you’ve still basically got the same water you had before – it’s not any different chemically.

So you can’t water plants that don’t like tap water with it.

But I would recommend letting your water stand for at least an hour or so, purely because it’ll be at room temperature, which your plants will like. Apparently plants like cool water when it’s hot but room temp is best the rest of the time to reduce the chance of shocking your plant.

Do I ever water my plants with water straight from the tap?

Yes, of course I do. Though only the hardy ones I think can take it. It’s usually because of poor organisation on my part and it hasn’t killed anyone yet, but I try to avoid it if at all possible.

As I’ve mentioned, I am experimenting with adding dechlorinator to my water (just the stuff my boyfriend uses for his fish tank water). I just put in a wee bit because I’ve never heard of anyone doing it, and why not give it a go?

So far I’ve noticed no difference, but tbh what am I expecting to happen? Wildly accelerated growth and blooms as far as the eye can see?

Rainwater

Seems wildly decadent but it’s really just a question of either setting up a water butt or putting some buckets outside. I have to collect some rainwater for my calathea and carnivorous plants, and we had a fucking AWFUL week weather wise last week so I’ve got plenty for everyone.

Filtered water

Water that’s had all the nasties filtered out when it’s passed through a membrane. I have way too many plants to be arsed with this, but if you want to, or have no access to rainwater, go ahead.

Distilled water

Distilled water is water that has been boiled, the steam collected and then condensed back. Purer than filtered water but not pure as pure can be, because some chemicals like chlorine and some pesticides have a lower boiling point than water and are therefore not filtered out.

Other randoms types of water you can use:

• Fish tank water
• Pet dish water (or any drinking water that would otherwise be wasted)
• Dehumidifier water

Watering in summer vs winter

This really harks back to the one rule you mustn’t break: don’t water your plants unless they need it.

In summer, the combination of warm weather and accelerated growth means that some plants may need watering every other day.

In winter, however, your plants may go for weeks without drying out – especially if your house retains its humidity. Just make sure you check the soil before you water. If you keep the soil too moist in winter it can encourage pests, and since we tend to check our plants less in winter, infestations can soon creep up on us.

Signs of underwatering

• Your plant dies
• Wrinkly leaves
• Slow growth
• Looks a bit sad

Basically all the signs we discussed before about being able to tell when your plant needs watering. But what to do about it?

What to do if you’ve underwatered your plant

Give it some water.

No shit, Sherlock.

The water might be hydrophobic though, in which case, it needs to be rehydrated.

Remove any brown leaves. They’re dead, there’s no saving them. If only part of the leaf is brown, then just trim it – it won’t grow back but it can absorb light and help your plant to recover.

If you’re very busy and/or travel a lot, it might be worth investing in either self-watering pots or those little globe things you stick in the pot to release water.

Or that thing you do where do put one end of some string on the soil and one in a bucket of water, like a very rudimentary self-watering system. It works…medium.

You may just have the wrong plants for your lifestyle. 

Ferns and calathea look beautiful, but they're quite demanding water-wise. 

Obviously succulents and cacti are the absolute bosses when it comes to living without water, but if you like your plants a bit leafier there are plenty of options - some philodendron, hoya, and pothos are all pretty chill when it comes to watering.

Signs of overwatering

Overwatering is a bigger killer than underwatering because the symptoms are often similar to underwatering, so the plant is watered again and the problem spirals. It’s also a much quicker killer, so the plant is unrecoverable before you’ve even noticed.

Here are some signs of overwatering you should look out for:

• Yellow leaves
• Leaf loss
• Wilting plant
• Weird smell/root rot
• Pests like fungus gnats
• Edema – lesions on the plant caused by ruptured cells. A few of my plants have it, especially larger ones.

What to do if you’ve overwatered your plant

If you’re worried that your plant is past help, then take a look at the roots. Ease it out of the pot and brush the soil away GENTLY. If the roots are gross and black and smell rotten, trim ’em away.

It looks bad (it IS bad) but it might survive. Make sure you repot the plant in well draining soil – mix perlite with house plant potting mix. If you have no perlite, mix it with sand.

If there are no roots to speak of, try putting it in a jar of water (only put the base of the plant in the water) and try growing some more roots.

This works well with things like spider plants and vining plants. Cacti and succulents will NOT appreciate it.

Now we wait. And hope. And buy ourselves a moisture probe so this never happens again. A lot of people claim they’re inaccurate – in which case, buy two and split the difference.

Tips for chronic overwaterers

• Terracotta pots will help to wick some of the excess moisture from pots

• NEVER put a plant in a pot that doesn’t have drainage holes in the bottom

• Stay away from certain succulents – string of pearls will HATE you.

• Go for moisture-loving plants: carnivorous plants love to sit in water, ferns don’t like to dry out, and calathea don’t mind a bit of moisture.

• Some plants are very forgiving of overwatering, but they won’t thrive: spider plants, pothos…even aloe will take a long time to die, although they look very distressed and floppy.

My watering schedule

One thing I would recommend is to keep your most finicky plants in high traffic areas so that you don’t accidentally forget them.

Your schedule will become easier over time once you’ve learnt which plants need a lot of attention and which ones don’t.

Places like guest bedrooms and weird corners are best reserved for plants that are happy by themselves for extended periods – ZZ plants, Philodendron, big plants that retain a lot of water (either internally or in the soil).

Every week I go around all my plants with a moisture probe. I’m trying to get into the habit of doing this BEFORE I clean the house, but I inevitably don’t and even more inevitably end up with soil all over the carpet. FFS.

I think everyone’s happy.

The important part of your daily plant schedule is just looking at your plants. Not even closely (unless you think there’s a problem), just taking the time to check no one’s collapsed or been eaten or produced a bloom.

I wrote this article about how I keep on top of plant care

All plants need watering

Yep, all of them. If you want them to thrive, that is. Cacti and succulents need more water than you’d think (mine like A LOT of water every fortnight-ish) and they vary a lot from plant to plant as to their water requirements.

Some of the thinner cacti go really wrinkly and sad when they need watering, but others (often the ones that are round and really fucking spiky) won’t tell you that they’re thirsty until they’re near death.

The important thing about watering cacti is that they don’t like sitting in moisture, so try to dry the soil out as much as you can.

Some people go to the effort of drying the soil with a hairdryer, but I’ve found that by bottom watering, they can take up all the water they need but the top remains dry so they don’t rot.

And that concludes my epic poem on watering house plants. I hope it helped. Now go and buy yourself a moisture metre.