Watering Indoor & Potted Plants
If you take into account over-watering and under-watering, moisture problems are by far the biggest killer of indoor plants worldwide. This is one topic that you can’t afford to overlook if you have potted plants in your house, and this article will give you what you need to tackle this crucial part of indoor plant care.
Know Your Plant
How can you hope to care for a plant that you don’t understand?
Research every plant you bring home so you know the type of soil it likes and how much moisture to give it. Plants differ a lot in their needs, and you might find you’re watering once a day for one plant and once a month for another.
Does it need a lot of water, or only a little bit? Will it do better in a well-draining soil, a moisture retaining mixture with a lot of compost, or perhaps a bit of peat moss?
Does it require regular misting of the leaves to replicate its natural habitat?
Will it be better off beneath the air conditioner, or on a windowsill in the bathroom?
How Often To Water Houseplants
The two most common problems that houseplants experience are over-watering and under-watering.
Over-watering is usually a sign over too much love, or poor drainage. When the soil remains wet for too long, plant roots aren’t able to breathe which will eventually cause the plant to show signs of distress such as chlorosis, crispy leaves that fall or stay attached to the branch, mold and root rot.
Under-watering is a sign of neglect, or poor watering technique. Sometimes, when you’re watering from above with a watering can or a cup, the water can take a short-cut through cracks in the soil, out the bottom of the drainage holes without the plant being able to access very much of the water at all.
In this way it can dehydrate, and you’ll normally see the plant lose vitality by showing yellowing of the leaves (chlorosis), shedding leaves, showing crispy leaves, or by wilting.
Given the choice between under and over-watering, I would always choose under-watering because this condition is much easier to correct and seems to be less deadly for most plant species.
Water disappears differently under different circumstances, and there are a few forces that impact this, primarily: temperature, humidity, soil mixture, and the amount of water that the plant transpires through its leaves.
A plant that transpires a lot in sand on a hot, dry day will lose water more water quickly than a plant that transpires a little in clay on a cool, humid day.
Some plants will tell you when they’re thirsty by drooping or losing a bit of general vibrance. Once you form a relationship with your plant and have been paying attention to it for a period of time, you’ll learn to see when its thirsty.
Another method of testing the soil moisture is by sticking your finger in to the second knuckle to feel for yourself, or to use a proper moisture meter. Generally, you will water only when the soil is totally dry, but this does depend on your plant’s needs because some plants prefer to keep wet feet.
Watering based on a schedule is for noobs and you’re better than that. Go ahead and test whether your plant needs watering yourself.
Soil Is Everything
If you’ve got the wrong soil, you’re really setting yourself up for failure.
Different plants have their own preferences when it comes to the texture, pH and amount of organic matter. Knowing your plant’s needs is imperative here; what works for one plant doesn’t work so well for another, even though they may look similar to one another.
You can purchase pre-mixed soil in bags, or you can purchase ingredients and make your own mixture of sand, wood chips, perlite, potting mix, compost, worm castings and other ingredients based on your plants’ needs.
You can read more about soil via this article.
How To Water From Below
There are two ways to water plants: from above and from below.
Watering from above is done with a watering can, a glass, or a pitcher. Often, this water takes a short-cut through cracks in the soil instead of soaking the whole root ball.
Water comes out through the drainage holes in the pot, so we assume that we’ve watered the plant well, but the plant still looks unhappy. At this point it’s easy to think that they’re something wrong with our plant, so we might reach for the pesticides.
We might even assume it’s over-watered, seeing as the symptoms can be similar.
The best way to water indoor plants can be to water them from below, which is done by filling a sink or bucket (I use a clothes bin) and dunking the pot in for a few minutes. You can do it so the water reaches the very top of the soil, or you can leave a small section of the top of the soil dry if you’re concerned about the water draining quickly enough to avoid over-watering.
Watch the bubbles rise as all of the air pockets fill with water, and be satisfied knowing that your plants are actually getting a very good drink. Once the bubbles have stopped, leave your pots for a minute or so, and then let them sit on the sink or out on the grass for a few more minutes to drain before taking them back inside.
Just make sure you know your plant’s needs and you don’t over-water your plants, which is so easy to do!
What Kind Of Water Is Best?
Tap water is usually fine, but it’s not technically the best option you can use. It contains heavy metals and chemicals such as chlorine bleach. Some plants can handle this and others are more sensitive so they may show symptoms of disease.
Hard water, or water that has percolated through limestone, chalk or gypsum, contains higher amounts of minerals than is healthy for most plants. Bore water is similar, and may even contain pathogens if not tested by a lab.
The best water to use is rainwater, followed by purified water and then distilled water.
Distilled water has been de-ionised and lacks normal minerals, which slowly erodes more nutrients from the soil than the other options. A re-mineralising solution can be purchased from aquariums and pet stores that people with fish tanks use.
Does The Temperature Of Water Matter?
Yes, it does. Plants are very sensitive to temperature, and if you use refrigerated water it may get tricked into thinking that winter has come early, trhyiggering it to go dormant. It can also damage roots and leaves if it’s very cold.
On the other end of the spectrum, if the water’s too hot it stands a good chance of shocking the plant and damaging the leaves and roots as well. It’s generally best to use water that’s room temperature.
Which Pots To Use
Most plants, with some exceptions, require the soil to dry periodically between each watering. As I mentioned above, it’s very easy to over-water plants so it’s imperative that your potted plants have access to drainage.
If the potting medium holds water, such as clay, peat moss or compost, watering from the top may be best. Watering from the bottom is a good idea for mediums that water struggles to penetrate.
Drainage holes in the bottom of pots are the most common form of drainage holes. When I take a new plant home, I will re-pot into a larger plastic pot if needed (otherwise I’ll leave it in the original plastic pot) and place this pot into a larger ornamental pot that doesn’t have drainage holes. I’ve heard this being called “double potting” or “cache potting”.
The second, larger ornamental pot looks nice compared to the plain, black plastic pot held within, and excess water is retained within the ornamental pot so it doesn’t get all over the floor or the table I’ve placed the plant on.
Avoid planting directly into an ornamental pot that doesn’t have drainage holes, otherwise excess water will be trapped, making it very hard to avoid over-watering (or under-watering in an attempt to compensate the risk of over-watering).
Some ornamental pots already have a drainage hole and these are perfectly fine to plant directly into, however you just need to think about where the excess water will drain into.
There is such a thing as a self-watering pot. No, this isn’t a pot that has a hose attached to it. Rather, it’s a pot that has a reservoir beneath the root ball for excess water to drain into, similar to the 2-pot system mentioned above, where we had 1 pot inside a larger pot that acts as a reservoir for excess water.
Self-watering pots work through capillary action, whereby water is poured into the reservoir, and is pulled up through the soil like a wick drawing wax up in a candle. Capillary action is also how trees get water from their roots up to the uppermost leaves.
When you’re setting up your pot, you can help the wicking action by using strips of fabric or rope that touch the bottom of the reservoir and goes up through the soil.
Water from the top the first time to get all of the soil wet, but don’t go so far as to drown your plant, seeing as once the reservoir is full the excess water will start to flood the soil.
Because the water is never drained out the bottom, and it only ever leaves the soil through evaporation or transpiration, all of the minerals in the water are deposited into the soil. Over long periods of time, this mineral content can become an issue as plants are sensitive to high levels of certain minerals like sodium.
Try using de-mineralised water which doesn’t contain any of those minerals.
Another potential issue caused by the fact the water never really drains fully is that self-watering pots can become mosquito breeding grounds depending on your location.
They’re also not ideal for certain plants that require dry feet like succulents and orchids.
Watering House Plants Without Making A Mess
Drainage is all well and good, but we want to avoid making a mess in our house.
You can place a saucer or dish beneath the pot to catch the excess water. One of these may come with the pot, or you may need to purchase one separately. It can be hard to find a matching one, but there are clear plastic saucers available for this purpose.
I personally use the double pot system mentioned above because I fin`d this method easier to water plants from the bottom; you can simply leave the ornamental pot where it is when you take the inner potted plant to the sink or bucket. I also like the look of the ornamental pot without a saucer.
How To Water Heavy Pots
It can be hard to know what to do when watering heavy pots. Above I mentioned that the ideal way to water plants is from the bottom, but it can be very difficult to lift a heavy pot into a sink, if it even fits that is. So usually watering heavy pots from the top is the only way to go.
Sometimes, you have a plastic pot with drainage holes inside of a larger solid pot without drainage. In this case, life is good because you can just water from the top, the water will come out the drainage holes and into the larger pot, so there is still a reservoir of extra water the plant can draw upon.
If the heavy pot has drainage holes, it’s going to be more difficult for you to water because moisture will come out of the hole and make a mess on the floor, even if you use a saucer to catch it due to the large size of the pot and the amount of water needed.
Plants in large pots with drainage holes still need an adequate amount of water, even if they are situated in a spot where you want to avoid water leaking onto the floor, so you just need to work around this problem.
A couple of solutions you could try are leaving towels around the base when you water to collect the excess moisture, or alternatively you can water a smaller amount more regularly. You could try watering 5 or 6 times in a single day on days where you need to water, to allow the water to soak into the soil instead of taking a short cut through a crack in the soil and out the drainage holes.
Some plants, for example those that come from rainforests and jungles, require a certain amount of humidity in order to thrive. Their ancestors have evolved in areas that had an abundance of moisture in the air and so their internal functions have adapted to this sort of environment.
These plants don’t do well in areas with dry air, whether it’s hot or cold.
You can still keep these sorts of plants in regions they wouldn’t normally thrive by creating or utilising an existing micro climate. This means putting them in an area that has slightly different conditions than other parts of the property.
For example, the area beneath the air conditioner is the wrong micro climate for a humidity-loving plant because the air conditioner physically dries the air.
Keeping a source of open water around is an “okay” way to add humidity to a micro climate. Water sitting in saucers beneath a pot plant (and other sources of water lying around) evaporate slowly and moisten the surrounding air. The downside is that small pools of water can be a breeding ground for mosquitos, and besides this method isn’t very effective anyway.
There are room humidifying products on the market that are available if you really want to take your humidity seriously, or place them in the bathroom where it’s more humid than the rest of the house.
Check the sort of potting mixture your plants are in, and the water needs of the individual species, and adjust your watering habits accordingly. Check for signs of under or over-watering and walk that line of keeping your plants moist but not wet.
Where To From Here?
You might like to check out my post on re-potting indoor plants without killing them, just so you know when it’s time to upsize, when it isn’t time to upsize, and how to upsize your little indoor plant babies.
Or, why not learn a little bit about a few plant health problems so that you at least have some idea of what to do next time catastrophe strikes.