How to water indoor plants?
Watering is another crucial part of caring for your plants, without which the plant would dry out and whither away. However, give your plant too much water and your plant will rot and possibly even die.
So how do we know how much or little water we need to give our plants?
There are a few variables to consider which I’ll go into detail below. It looks like a lot to consider, but just bare in mind that most plants are pretty forgiving providing that it isn’t neglected too often!
Light – discussed in much more detail in our post on light (which can be found here) we need to consider how much light the plant will be getting. The more light it gets, the quicker the plant will use up the water it has, the lower the light the slower.
Soil composition – Again discussed in much more detail in our post on soil (which can be found here). The better draining the soil is, the more often and higher the dose you will need to water your plants with – the lesser draining the soil is, then the less often you will need to water your plants and in lower doses.
Temperature – the warmer the temperature the quicker the water will transpire/evaporate, the cooler it is the less this will occur.
Pot Type – What kind of pot you are using, plastic pots will retain moisture in the soil to a much greater extent than using a terracotta pot.Terracotta is very porous so will wick moisture out of the soil and therefore will dry it out at a greater rate.
Pot size – The larger the pot is and the more substrate in the pot, the longer it will retain the moisture, the smaller the pot and the lower the amount of substrate, the quicker it will dry out.
Ventilation – The more air circulating around the plant and the soil, the quicker the water will transpire/evaporate. Less air circulation means less transpiration/evaporation.
Natural habitat of the plant – Where does the plant originate from? Is it a jungle plant, therefore conditions consisting of high humidity, dappled sunlight through the forest canopy, Moist well draining organic material? Or perhaps more desert conditions where the air humidity is low and the soil dries for quite a while between heavy infrequent rainfalls. We would definitely recommend visiting your local botanical garden to get a better understanding of how your plant lives in it’s own habitat.
These aren’t all the variables, but the they are the main ones to consider and will make the strongest difference. To put these into context we will look at a couple of scenarios to make sense of this.
Scenario 1 – Picture a hot, sunny day and your jungle plant, in it’s medium sized terracotta pot and well draining substrate mix, is sat near a bright window where it is receiving dappled sunshine simulating it’s natural habitat. In these conditions, it would be transpiring/evaporating the water fairly rapidly due to the warm temperature and bright sunlight. The well draining substrate mix in the pot, wouldn’t hold onto the moisture as well, relinquishing it faster, especially when considering the terracotta pot would be wicking the moisture at the same time. We would therefore have to be more vigilant of keeping the water topped up or else the plant would dry out. To slow down the rate of moisture loss, we could change the pot to a plastic pot to prevent the moisture being wicked away – increase the pot size so that there is more substrate to retain water, or possibly even lessen the degree of drainage by adjusting the substrate composition (reducing the amount of perlite etc.) – Or reducing the amount of light the plant gets by moving it further away from the window (We wouldn’t recommend the last option – To enable your plant to grow big and healthy it needs as much light as possible without scorching the leaves).
Scenario 2 -Picture a cold, overcast day and your jungle plant, in it’s medium sized terracotta pot and well draining substrate mix, is sat on the opposite side of the room away from the window. It would transpire/evaporate it’s water at a fairly slow pace due to the low temperature and low light. Even though the substrate is a well draining mixture and the terracotta pot is slowly wicking the moisture away, the little light and warmth means that the plant isn’t actively using very much water at all. We would therefore have to be more vigilant of over watering as the plant could rot and possibly die. In this circumstance, we could reduce the amount of water retained by decreasing the size of the pot (if possible) to reduce the amount of substrate and thereby reducing the amount of moisture it can retain. We could improve the soils draining even more by increasing the ratio of perlite/orchid bark in the substrate – Or we can increase the amount of light reaching the plant by placing it nearer a window or possibly even grow lights.
So how can you tell when to water your plant?
There are several methods to use, but the following three are what we use, sometimes all 3 at the same time to ensure we are getting it right:
Testing the soil with your finger – touch the surface of the soil with your fingers, if it feels moist then it is still fine and doesn’t need water. If it feels dry, then prod your finger around 2 inches into the soil and if it still feels dry then it is definitely time to water.
Pot weight method – With experience, you’ll know whether your pot feels light or heavy, if it feels light then this is a good indication that the plant needs water, if it is heavy then it may be fine. This method is certainly the least effective so it is best to do in conjunction with the ‘finger in soil’ test.
Moisture meter – Without a shadow of a doubt, getting your hands on a moisture meter will take away the guessing game and make this whole process much simpler. Moisture meters are relatively inexpensive and very straight forward to use (you can even purchase one from us here). It has a long probe which you insert into the soil as far down as you estimate the roots to be (take care you don’t damage the roots – aim a little off to the side). The scale at the top will then give you a reading – ours has a scale of 1-10 and an indication of ‘dry / moist / wet’. The sweet spot being ‘moist’ between 3-8, either side of this is an indication that the plant is too wet or too dry.
Which water to water your plants with?
Now that we have covered the variables and the different ways to tell if your plants need watering, the next thing is to choose the water you are going to water your plants with. Below are not all the best sources of water, but the best sources that are most accessible to most people. They are listed in best to not quite as good (you got to do the best with what you can, so ultimately tap water will still do a great job!):
Rain water – if you can collect rainwater in a clean container, this will be the best source, the most clean and natural, and the cheapest – It’s free once you have the cost of the set up to collect water out of the way.
Distilled water – Distilled water is water that has been heated up and turned into a vapour, which is then cooled and then condensed back into water. This purifies the water and makes it an excellent source of water for your plants. This method is cumbersome and tricky to do yourself so you can just buy it, however this may prove to be quite an expensive method of providing water for your plants.
Filtered Water – If you can get a Brita Filter jug or some alternative, then run tap water through this and it will take out a lot of the impurities and salts that linger in your tap water. This is mostly what we use and helps prevent brown edges on leaves with some of the more sensitive variates of plants like prayer plants. The brown edges come from build up of salts derived from tap water.
Tap water – Tap water will also work fine, just bear in mind that if your tap water is especially ‘hard’ then you will likely have not so pristine leaves on some of your plants, but this doesn’t bother everyone. A quick way of seeing if you have hard water is to look at the inside of your kettle, if it is absolutely caked in lime scale, this is a good indication that you have ‘hard water’. You may be lucky and not have this problem and will mostly be fine to use this on your plants without any defects.
How to Water you plants?
So the final thing to consider is how to actually administer the water to the plant! Again there are a few different methods, you will need to factor in all the variables that we talked about earlier in this post and whether the following method is suitable for that particular plant before commencing with it, but the following methods are the ones we use:
Pouring water over the top of the soil – Pretty much the standard way of watering your plants, take a watering can or or jug etc. And carefully pour the water around the top of the pot to let the water soak and drain down through the pot. You will need to consider the amount of time it will take the soil to dry out with the quantity you are adding, over do it and the soil will stay too wet for too long, so perhaps best to go with caution and add little but often – especially in the colder, darker months!
Bottom up watering – If your pot has a drainage hole at the bottom, you can sit your pot into a few inches of water for 10-15 minutes. This will allow enough time for the roots to take the water it needs without soaking the soil too much. Only the bottom few inches will be soaked, the rest of the soil will slowly saturate to a moist level if it is allowed to sit long enough.
Showering your plants – We almost exclusively use terracotta pots with a drainage hole for our plants and very well draining soil, so would only recommend the showering method if you have a similar set up, it’s during the summer months, and the plant will be in a bright spot and will actively use the water at a faster rate. This method is a little more ‘advanced’ so would only do this after you have a better understanding of the drying out rate of the plant you want to shower. We wouldn’t want you to go and kill any of your own plants after reading how we water our plants!
So with all this in mind, put the plant in your shower and shower with Luke-warm water ensuring the water pressure isn’t too severe (don’t want to power hose the leaves off!). Shower the top and underside of the leaves and flush the pot through thoroughly. This cleans bacteria form the leaves and is good for pest prevention, plus gives your roots a deep clean of any salt build up on the roots and gives them a through drink too. This is similar to how plants usually receive their water in the wild, so is our favourite method – But can’t stress enough that this is only suitable for quick drying, well drying soil conditions.
We hope this clears up a lot of the questions you may have about watering! Unfortunately there is a learning curve with all of this and there may be a few casualties along the way… Put this down to experience and keep going, it will become second nature eventually and you’ll get so familiar with your plant you’ll ‘just know’ when the time is right.
We wish you all the best!
Little Eden Tropicals.