The number one question we get asked here at Greener House Nursery is “When should I be watering my plants?” As over-watering is the number one killer of all indoor plants, we figured we’d better set the record straight. There are quite a few variables in finding the answer to this question, so in this article we will give a general guide to help you get started and hopefully dispel any misinformation that is out there.
The second part to this watering question, that often gets forgotten, is how you should be watering. The technique you use to water will greatly affect the plant’s health and the frequency that you water. I generally group indoor plants into two distinct groups when it comes to watering technique.
Group One: Water a lot, but not very often
This group encompasses the majority of indoor plants. The key is to water a huge amount but not very often. This method allows the soil to fluctuate between wet and dry. As you’re starting to collect a few plants it is important to remember that they are not the same as cut flowers. They do not want to be sitting in water and are very well-adapted to drawing moisture out of their surroundings and storing it for later.
For this method, we take the plant in question and soak it for at least an hour or even overnight. By partially submerging the pot, the water is able to wick up through the soil and achieve an evenly distributed amount of moisture throughout the soil. This takes TIME to happen. Soil can become hydrophobic and needs time to sit with the water to properly re-hydrate.
The amount of water that the plant is soaking in should be enough to cover the drainage holes in the base of the pot (about 2cm deep). More water is okay but if it’s too high, very dry soil can tend to float. If your plant has a deep tray or water reservoir in the base you can fill these. If not, you can partially fill up a sink or bucket. I fill my laundry sink up and water several plants at once. Usually the water comes up to about halfway up my pots. I soak them overnight and then let them drain in the same sink before putting them back.
Water the plant from above at the same time. If you can wet down the leaves and stems this can help to clean them and kill any pests. Use a wet cloth to wipe off any persistent dust. I usually start with this to avoid any overflow as much of the water will run through the soil and out the bottom.
I usually water about once a month in Winter and once every one to two weeks in Summer for mid sized plants. I am waiting for roughly the top third of soil to be totally dry before even considering watering as a minimum. For most plants you can allow more of the soil to dry out without any damage to the plant. Many plants will start to wilt if they stay dry for too long, at this point it is best to water but in many cases you still have up to a month before that plant will be damaged. This is why I always tell new plant collectors that if they are unsure if it is time to water, then DON’T! The plant will visibly tell you when it is time and after a while you will begin to gauge how much water your plant needs better. However if you water too often your plant will very quickly be damaged, and will take a long time to repair.
In summary, we are watering the soil from above, below, and washing down the leaves with a large amount of water so that the soil becomes 100% saturated. This means that the plant can make use of all hydrated soil and can form a healthy and robust root system. Solely watering from above will usually result in huge dry patches forming underneath the top layers of soil. The plant has less soil to work with and will need more regular watering to survive.
Group two: Water regularly, but not much
This group of plants generally includes ferns, palms, and calatheas. The goal with this watering technique is to maintain a more constant level of moisture with regular small waterings. When soil is kept moist it will take up and distribute the added water quite easily, and often not that much will end up draining out.
Once the top 1-2cm of soil is starting to dry out I will add a jog of water to the pot. This is roughly about once a week in Summer and once every two weeks in Winter. Some plants are happy to stay a little bit more moist and some like to dry out a bit more but this is a good rule of thumb to get started.
I will usually try to pair up plants in this group with a tray to make the more regular waterings a bit easier. Remember that the goal is to have the soil moist, but not wet.
Certain variables will change the rate at which your soil will dry out. Some of these include:
- Light levels
- Air flow
- Inside vs. outside
- Pot size
- Plant type
- Soil type
Self watering pots and trays
The marketing around self-watering pots makes them sounds like a huge time saver but they are usually the reason your plant is dying. You must empty the water reservoir, and you cannot use the self watering function otherwise the soil will stay saturated and kill your plant. The inbuilt tray is mostly there to protect your furniture. Once the plant has finished soaking up as much water as possible, empty out the excess. Do the same with any trays that you keep under your plants. If they are still full after 24 hours, you should definitely tip them out.
There are only a select group of plants that actually like to use the self watering function, such as maidenhair ferns which love to be soaking wet all the time.
A lot of the plants will benefit from misting but only a handful actually require it. Try to mist in the morning so that the leaves can gradually dry out during the day. Misting at night may result in water sitting on the leaves and causing damage.
Try to focus on misting the newest leaves as they are usually the most susceptible to damage from low humidity. Avoid rewetting the soil.
Plants that commonly require a humidity boost include Fiddle Figs (Ficus lyrata) and Calatheas (Maranta/prayer plants).
Keeping the plant in its original plastic pot is totally fine, if not preferable, in many situations. If you decide to re-pot, the new pot should have at least one drainage hole. Keep in mind that a lot of the common indoor plants actually like to be in cramped pots and putting them in a huge pot may kill them, partially because all the extra soil stays too wet for too long.
If your plant is re-potted directly into a vessel that has no drainage then it will die. It may not happen immediately but it will happen. Many companies sell pots with no drainage, which are just meant to be used to cover the plastic nursery pot. This is totally fine! Simply place your new plant inside the decorative pot. This cover pot can be used essentially as a tray making watering nice and easy, just make sure to empty out the excess water after a few hours.
Too much water in the soil may result in numerous problems occurring including fungi, bacteria, and insects may be able to infest the soil, the plant roots will not be able to able to access oxygen, take up nutrients and may rot. Leaf tips will often blacken, leaves can wilt, and also die off completely. Damage from over-watering can take a long time to recover from.
Generally too dry will not kill your plant but too wet will. Look to the plants natural habitat for a more accurate understanding of what they actually want. Make sure to speak with your local nursery before you make your purchase to get lots of information, and if they don’t know what to do then that probably means they aren’t taking great care of the plants they have in stock. When you shop with a small business you are dealing with the people who are there everyday and know what every plant has been through. Shop local.
Disclaimer: This article is for beginners. It is meant to give a general sense of how to water and help new plant collectors to keep their plants alive. If you are looking for more in depth information check out one of our plant care guides.