The most basic and common task for any plant parent is to water their houseplants. Each individual plant has different needs that determine how much water they need.
You don't want to give too little water or too much. But what exactly is "too much water"? Why does the pot size matter and what's the best time of the day to use the watering can? Can you use hard water, and what are the golden rules for doing it correctly?
So many questions! It's easy to feel this is a complex subject to grasp. But I promise that it's really not. Yes, things can go wrong, but this guide will help steer you in the right direction.
Some houseplants will need frequent watering, others will need less water, it all depends on the type of plant - Photo By Cottonbro
The first thing to remember is that as a general rule, most houseplant owners starting out will either overwater their plants or underwater them. Not surprisingly these are the two biggest reasons plants fail in people's homes.
It's a fine balancing act to get it spot on. But it's easy to learn the skills needed to pull it off successfully. All you need is to remember the basic principles and this guide will help you understand how to get it right.
There are three main ways to water your plants. Sometimes it's about what is most convenient for you, other times it's simply about preference. However it's almost always best to water heavily once, then wait until the soil starts to dry out rather than little and often.
Probably the most commonly used method for watering plants. And the most obvious. You just drench the soil surface from the top and allow the water to filter through the pot by gravity.
Although it's quick, it's less accurate than the other methods below and so it's always best to have the pot sitting in a container or drip tray to catch any water that comes out of the drainage holes at the bottom of the pot.
If your container has no drainage holes for excess water to escape, you have to be so careful you don't overdo it as water sitting around the potting medium will result in wet or soggy soil that can lead to root rot.
The plant pot sits in a container like a drip tray or a bowl of water and you just fill the container up. Eventually the water will be sucked up into the dry root ball.
If the container is relatively small, you may need to do this a few times until you can see that no more water is being drawn up. Be sure to tip any excess water that is still in the tray away after half an hour to prevent potential root rot.
READ MORE - Is it better to bottom water or top water plants?
Potting soil will normally absorb water like a sponge. But brand new sponges won't absorb water until you've submerged it and squeezed it a few times to force the air out. The same thing happens with most potting soils if the growing medium is allowed to dry out fully.
If your plant's soil is no longer absorbing any water, and you notice water running through the plant pot and out the bottom in seconds, then it has lost the ability to absorb moisture. The Immersion Trick will solve this though.
Tip
This watering method carries a risk of spreading diseases or pests if treating multiple plants in the same water. Ensure your plants are healthy, or ensure the "sick" one goes in last.
All you need to do is fill a large container, like a washing up bowl, with room temperature water and then lower your plant pot into it, just so the water level reaches the top of the pot.
The pot may try and float, if this happens hold it in place.
Bubbles will rise to the the surface, and when they stop (after a few minutes) the root ball will be fully saturated with water and you can remove the pot from the water.
Lots of people swear by the Ice Cube watering hack. This might be a good way to water your plants in certain circumstances. If you want to learn more, we explore this topic and give our personal experience and recommendations over in this article.
Hi, I'm Tom!
If you're like me and enjoy the challenge of growing houseplants and getting them to thrive, then Ourhouseplants can help. This website shares my knowledge and years of growing plants and provides (hopefully) helpful advice on properly caring for your indoor plant friends.
The best water you can use is rainwater or bottled water because they're the most natural and have the correct PH for most houseplants.
However both of these options can be impractical or expensive in the long term, so tap water is the most commonly used type of water.
In most situations, tap water does not cause any problems; however, if fluorine or chlorine is added to your tap water, some plants like Spider Plants or Dracaenas can be susceptible to this. Certain fussy tropical plants can also look sickly over time.
I personally water my Spider Plants and Dracaenas with tap water and have done so for many years without any issues. My country does mandate fluorine being added to tap water but potentially it's less than in other countries. So I'd advise watching for issues and switching to something else if problems occur.
If you live in a soft water area you need to carry out an occasional step to avoid issues once every four months or so.
This is because soft water contains sodium, also known as salt, that will build up in the soil, which will eventually disrupt the natural transfer of minerals and water into the roots and the long term health of your plant.
Top Tip
When flushing the soil, you're washing out everything, good and bad.
Be sure to provide fertiliser as you will also wash out nutrients in addition to the salt by doing this.
To avoid this happening "flush" the pot. All you need to do is pour water into the pot from the top for a minute to wash the salt build up out of the drainage holes at the bottom.
If you live in a hard water area like me, this will generally contain minerals like limestone. I pretty much always use tap water with no problems.
Occasionally, with plants I've not repotted for several years, you can see a build up of limescale on the inside of the rim of the pot or on the soil surface. You can remove the top layer of soil whenever you repot your plants if you get this too.
Clay pots can also show harmless white deposits when you use hard water or even softened water. They won't harm your plant, but can look unattractive. You can wash the pots to help remove the white marks and some people will even use linseed oil.
The answer to this usually comes down to experience and practice. There isn't a hard and fast rule to follow, it's a simple case of observing your plant, and interacting with it.
Houseplant's are not keen on a strict routine.
You may hear your neighbour saying she waters all her plants heavily every Sunday morning without fail.
Such watering schedule are often unlikely to work long term and are only setting you up for problems later on.
Each plant has their own likes and dislikes when it comes to watering, even two plants of the same type could have differences. For example their location and size will vary and affect how much water they need.
By "interacting" we mean either looking at or touching the soil surface and just below that to see if it is moist or dry. If the soil surface and the first inch below is dry, it's likely time to water your houseplant. If the soil surface is still damp, no more water is needed.
If your plant's not too big or heavy you can also pick it up; a pot or container which is heavily saturated with water will be much heavier than a pot that has completely dried out. The weight of the pot can help gage the overall moisture level and indicate if more water is needed.
Helpful instruments, like a moisture meter, can be brought that indicate, beep or light up when it's time to water again. Here's an example on Amazon with positive reviews. (Affiliate link).
There are several other important factors and signs that will tell you it's time to water your houseplants. This article will give you the full breakdown.
READ MORE - How often should you water houseplants? - Photo by Kaufmann Mercantile
If you make watering mistakes, your plant will normally tell you something is wrong. It's a good idea to look out for any of these on a regular basis to help prevent more serious issues later on.
Under-watering and over-watering cause very similar warning signs in houseplants
If you've carefully read the two lists above, you might think I've made a mistake and copied the same signs into each. Unfortunately, it's no mistake, frequent underwatering and overwatering cause very similar warning signs in houseplants.
It's not all doom and gloom though, if you ever see any of the symptoms listed above you will just need to rely on other methods to judge (such as pot weight / touching the soil / common sense etc) and make an educated decision as to which type of watering mistake is causing the problem, and adjust accordingly.
Further reading -
Am I Overwatering my houseplants? - 8 Clear signs to look out for
Many houseplants don't mind if you water them in the morning, afternoon or evening. However as a general rule, its best to avoid watering any plant in the evening when it involves wetting their crowns or exposed stems.
Is it OK to water houseplants at night?
Yes!
The idea behind this is that if you do late in the day, the water will sit on the plant and when the temperature drops at night it can encourage plant rot or fungal diseases.
If you watered that plant in the morning, the water should have subsided or evaporated from the crowns / exposed stems by nightfall. However unless it's the middle of winter or your plant has been put in a spot that gets very cold during the night, watering late in the day is unlikely to be a problem.
Although it's an important task, watering is usually a quick and painless process, but sometimes there is something wrong with the soil which causes issues:
This is caused by a very dry surface soil. You don't typically get this unless your potting mix contains high levels of clay, for example if you have used garden soil instead of potting compost. Or the soil is completely bone dry.
The solution is straight forward however, just prick the surface with a fork or small trowel to break it up a little, then try watering again.
A watering can with a long spout can help you aim when watering the top of the soil of a potted plant - Photo by Kaufmann Mercantile
This is almost always caused because the soil has dried out completely. This results in soil pulling away from the edges of the container creating a clear channel for the water to drain through. The soil therefore does not have a chance to grab any of the water that is quickly passing by.
The solution is to follow the Immersion watering method above, if that isn't practical you can try Bottom watering.
Over the last 20 years, Tom has successfully owned hundreds of houseplants and is always happy to share knowledge and lend his horticulture skills to those in need. He is the leading content writer for the Ourhouseplants Team.
