Bottom watering allows plants to absorb water from the bottom up through capillary movement throughout the soil when placed in a watering tray. The plant is then removed from the tray after 15 to 20 minutes and the excess water is allowed to drain freely from the soil.
The soil remains moist for 3 to 4 days before it can be bottom watered again.
In this article, we will outline how bottom watering works as well as the steps you can take to bottom water your plants with total success based on our years of experience. So have a read and learn how bottom watering can benefit your plants.
What is Bottom Watering
Bottom watering is applying water to plants from the bottom up. The flow of water is opposite to the conventional watering method and is pulled up into and throughout the soil by capillary movement.
Plants are placed in a bottom watering tray and allowed to sit for 15 to 20 minutes.
This method of watering proves to be effective from our experience as it gives the water enough time to move into and fill the entire root structure.
The roots are now exposed to more nutrient availability from the surrounding soil. In turn, this has resulted in healthier plants with lush green leaves.
Interested in bottom watering trays? I have found some cost-effective and durable trays which worked well for all my plants. You can find them by clicking here.
How Bottom Watering Works
Bottom watering works by the soil’s ability to absorb water through upwards capillary movement.
A point to note is that not all soils will have the same rate of absorption.
The rate of absorption is dependent on the soil’s structure and the type and quantity of amendments in the soil.
However, there are a couple of things that can prevent the bottom watering process from not working and the quality of soil is one of them.
Bottom Watering tips
- Bottom water plants that are easy to handle
- Ensure that the plant pot has holes at the bottom
- Water until the top of the soil is moist
- Have a separate container to place the plant after bottom watering to drain out excess water
- Use a dedicated flat container larger than the size of the plant
- Consider adding fertilizer when bottom watering depending on the plants nutrient requirements
- If you have a lot of plants like myself, rotate the bottom watering schedule for different plants so it doesn’t seem like a burden.
How to Bottom water plants
Step 1: Fill your tray or container with water so that it will reach 1 inch from the bottom of the soil in your planter.
Note: Different types of soil will absorb the water differently especially if there are rocks at the bottom of the planter, which has to be compensated for by adding enough water so that it reaches 1 inch higher than the rocks.
Step 2: Place your plants in the tray which contains the water.
In my experience, with smaller plants that have really dried out soil, when placed into the water the plant and soil can come straight out floating. Don’t worry just leave it there and it will eventually soak and settle back into the container. Now may be a good time to consider repotting the plant as I have done.
Step 3: Let the plants sit in their bath for about 15 to 20 minutes before you check the moisture content of the soil.
What I have found is that when the top of the soil is moist to the touch then you can remove the plant from the watering tray.
If the top of the soil isn’t moist after the time has passed you can simply add some water to the top and allow that to drain so that the total mass of the soil is moist.
Step 4: Drain the water out of your sink and let the plants hang out for a few minutes to drain.
As the water is absorbed into the soil the water level will drop in the watering container. This is perfectly fine. If all the water has been used from the container and the top of the soil does not feel moist to the touch then you will have to top up additional water into the container.
From watering my many plants using bottom watering, I have found that most of them would take up the water straight up to the top of the soil and very few may not.
This is not a cause for great concern, however, there could be something going on with that soil and you should look into it.
Most times, repotting the plant with new soil and soil amendments will help a lot!
Additionally, there are some places that make bottom watering fun and easy and can help prevent any mess caused by spilled water such as sinks, the bathroom, and even outside.
Bottom watering can be done on –
- Terracotta Pots
- Fabric Planters
- Ceramic Pots
- Plastic Pots
- Concrete Pots
- Metal Pots
Plants that Bottom Watering Works Best with
Bottom watering is an excellent technique used for small and medium-sized plants. The method is not suitable for heavy and tall plants.
For example, if you have African violets and apply water from the top, they will develop discolored leaves.
Some root-bound plants do not allow the soil to soak enough moisture, but you can avoid this problem through bottom watering.
Likewise, if you have watermelon peperomia, you can use the bottom watering technique because they do not like wet leaves such as piggyback plants.
Plants that Like Bottom Watering.
- Dragon tree
- Fiddle leaf fig
- Spider plant
Bottom watering also works great with seedlings and we have written a detailed article on how to effectively do it. See the Article here.
Can you Bottom Water Succulents?
Yes. You can bottom water succulents.
Bottom watering succulents ensure that the plant is not overwatered by providing the ideal amount of water to the soil. The soil takes up only the water that it can hold, after which, it drains freely leaving the soil adequately moist. Bottom watering succulents prevent soft and mushy leaves associated with overwatering.
Advantages of Bottom Watering Plants
The advantages of bottom watering mainly come from the growth of the plant roots promoted by the even distribution of water through the soil. As the entire soil structure becomes moist it stimulates the plant root to spread and access all the nutrients the soil can provide.
Bottom watering allows the soil to remain moist for a period of time which enables plants and seedlings to get only the amount of water that is required for proper growth and development.
I have seen that the plants that I have watered using this method grow consistently well without worrying about them being overwatered.
By using a simple touch test you can determine when to remove the plant from the tray. We have found this time period to usually be between 15 to 20 minutes for most plants.
Helps plants develop Stronger roots
As the entire soil mass is exposed to water through the wicking action of the water from the bottom to the top, roots tend to grow more healthy as they receive only the required amount of water that they need.
There is no avenue for water to crowd the air spaces to stifle the roots of oxygen which can lead to root rot and other fungal diseases.
Roots spread Evenly throughout the Soil
When plants are watered from the bottom the roots of the plant spreads evenly through the soil’s mass which in turn provides better support for the plant both physically and nutritionally.
The nutritional benefit of this is that when the roots spread evenly through the soil they can maximize the uptake of nutrients to the plant by accessing all the nutrients the soil has to offer.
This results in healthy plant growth.
Reduces Plant Pests and Fungal diseases
Bottom watering keeps the surface moist for a short period, allowing the leaves to flourish by decreasing pests’ development.
Fungus gnats are small flies that infest soil. Their larvae primarily feed on fungi and organic matter in the soil, but also chew roots which can be a problem. These flies love overwatered soil because the moisture provides the ideal environment for them to reproduce.
Bottom watering prevents gnats from infesting the plant’s soil by not allowing water to accumulate at the surface for prolonged periods.
Additionally, by preventing overwatering also prevents the onset of root rot which is caused when water overcrowds the roots and prevents them from absorbing oxygen from the surrounding air spaces.
Disadvantages of Bottom Watering
There are several downsides of bottom watering besides its many benefits.
Bottom watering can lead to the accumulation of minerals and salts in the soil, weakening the roots and causing root burns.
It is easy to use tap water to bottom water plants and for good reason, it is most readily available and is, in most cases, safe for plants. I, myself, use tap water.
But continual use of tap water to bottom water plants can eventually lead to salt and mineral build-up on the roots which can prevent them from absorbing nutrients.
This leads to burning of root tips, stunt growth, and rotting. Plant cells have membranes, which allow water to enter while keeping larger salts out.
What I do suggest is that once in a while you switch it up. Water the plant from the top with some distilled water or rainwater which will remove any build-up of minerals from around the roots.
Bottom Watering Larger Pots
Bottom watering is somewhat problematic for larger plants. If you have larger plants at home, they will take a lot of time to absorb enough moisture.
The problem worsens if your plants are in terracotta pots. That’s why you have to create the right balance between the bottom and top watering your large plants.
Larger plants can also be very heavy to handle and any mishaps can lead to damage to both you and the plant.
Additionally, there are bottom watering systems that allow for plants especially in larger pots to be bottom watered with a built-in water reservoir that waters the plant when filled.
Now it’s sad to say, but I find myself finding it hard to keep a routine of bottom watering all my plants.
Apart from some of them being so heavy to handle, I really don’t want to strain myself by lifting 20 plus heavy plants to bottom water every few days.
Honestly, it can become a burden even from a plant lover like myself.
What I do suggest is that you selectively bottom water your plants if you have a lot.
Rotate the watering regime so that it doesn’t seem like it’s draining the life from you. This really helped me with my many plants.
What also helped is these watering trays that I have found to be really durable and easy to handle.
How Often Should you Bottom Water Plants?
Bottom watering follows the same methodology for watering plants which ensures that the plant is receiving only the required amount of water.
Plats should be bottom watered twice on a weekly schedule. Bottom watering provides the soil’s mass with enough water to last between 3 to 4 days. The soil will start to dry out from top towards the bottom which gives the roots enough time to absorb the required amount of water before it can be watered again.
For a more detailed account of when to bottom water plants and the factors that affect the process, you can see our detailed article on how often to bottom water plants.
When to Bottom Water Plants?
The best time to bottom water plants is during early mornings, late evenings, and at night. Bottom watering during the day (between 10 am to 4 pm) can reduce the time it takes for the water to soak into the soil. Bottom watering should be done when the soil is dry for best results.
However, there are surrounding conditions that can affect how well bottom watering works which dive fully into in our article when to bottom water plants.
Best Water for Bottom Watering
The best type of water for bottom watering plants is rainwater. The quality of water influences the growth of the plant. Different types of water such as tap water, pool water, well water, mineral water have different minerals and nutrients values and not all types are ideal for bottom watering plants.
Tap water or municipal water is supplied through a tap, a water dispenser valve. It comes from a treatment plant that removes contaminants and purifies the water before it is pumped out and eventually reaches our homes.
According to the Centers for Disease Control and Prevention (CDC), the United States has one of the world’s safest drinking water supplies (Source).
For me, if it is safe to drink then it is safe to water plants. And rightfully so, I have watered my plants with tap water for years and haven’t seen any side effects when it comes to plant ailments.
However, depending on your location and environmental conditions the water in the tap may have contaminants and if you suspect that it does then you should consider other more viable water options for the health of yourself and your plants.
As previously discussed, tap water can have some downsides with respect to minerals and their deposition on the roots over time.
Rainwater is the best water you can use to bottom water your plants. Rainwater contains a small amount of minerals which include calcium, magnesium, and iron. In addition, it is slightly acidic with a pH ranging between 5.5 to 6.5. The slight acidity promotes nutrient availability for the plant.
While it is relatively low in mineral content, it is also free of toxins, such as fluoride and chlorine.
I have tried bottom watering with rainwater and it never failed.
The only thing is that it might be a bit tricky setting up a viable method for collecting the water.
However, in some states, the collection of rainwater may be illegal. Colorado and Utah are the only states that are currently heavily regulated to keep homeowners from harvesting and using the rain that falls on their property.
Well-water is groundwater that is untreated. The well is drilled down into an aquifer, which is an underground layer of permeable rock containing water.
Apart from tap water, well water is one of the cheapest water which may be available for plants.
The water filtration through rocks that ends up in the well can contain many essential nutrients for plants including potassium, calcium, iron, and magnesium.
However, in some cases, it has been found that through this same filtration, pollutants such as mercury and high nitrogen levels may also be present in the water which can severely affect your plant’s health as well as yours.
Distilled water is a type of purified water that has had both contaminants and minerals removed.
The distillation process boils the water and then condenses the steam back into a liquid to remove impurities and minerals.
By far this is the cleanest form of water you can provide for your plants but it has some work as well as an added cost of boiling the water.
This water also adds no minerals to the soil so I would suggest that you stick to your fertilization schedule to ensure your plants are getting the required minerals that they need.
Can you Overwater from Bottom Watering?
No. Bottom watering plants will not lead to overwatering because the soil will only hold a certain amount of water-based on the bonds between the water molecules and the soil as it opposes gravity. Any additional water will not be absorbed into and held in the soil during bottom watering.
The water supply will be used up to an extent that the soil cannot hold anymore. Excess water in the soil will drain out when the plant is removed from the bottom watering tray or sink.
Essentially, bottom watering prevents overwatering by allowing the water which was absorbed into the soil to drain freely out the soil through the same way it entered.
Can Bottom Watering Affect Soil?
A good bottom watering soil should have good aeration and spaces for the water to be properly absorbed when the plant is being bottom watered.
The effect bottom watering has on soil is that it moistens the soil and allows stale air to be pushed out by the water during the process and fresh air to be drawn back in when the water is drained.
Bottom watering affects soil in a positive way such that the soil is well moistened after watering which allows the mineral ions within the soil to become available for the plant to use in a well-oxygenated (aerated) environment.
The benefits bottom watering has on soil are:
- A Healthy Microorganisms Population
- Improved aeration
- Improved mineral availability for plants
- Prevents soil compaction
Adding Fertilizer when Bottom Watering
Bottom watering stimulates root growth and adding fertilizer when doing so, can help boost plant growth at the same time.
Fertilizer can be added when bottom watering. Bottom watering allows the fertilizer to move with the water up into the soil. This allows the nutrients from the fertilizer to be available to the plant’s entire root system.
When bottom watering, a water-soluble fertilizer should be added with the water once a month during the growing season.
Adding the fertilizer with the water allows the nutrient to travel upwards and soak into the soil during the normal watering regime.
We have written a more detailed article based on our experience with adding fertilizer while bottom watering.
Bottom Watering vs Top Watering
Bottom watering plants keep the soil uniformly moist so the entire root structure gets watered, however, the downside to this is salt build up over time.
Top watering encourages the presence of fungus and gnats while the water can be channeled out of the soil, not being able to reach the entire root structure.
However, using them together can eliminate these problems.
We have written a detailed article on Bottom watering Vs Top watering.
|Bottom Watering||Top Watering|
|Prevents Overwatering||Can can overwatering|
|Prevents Pests||Can cause leaf fungus|
|Promotes Better Root growth||Cause root rot from overwatering|
|Waters the entire soil||Water can channel out easily|
Bottom watering is an easy way to allow plants to absorb only the water that they need. It involves placing the plant in a watering tray and allowing the water to travel upwards into the soil via capillary movement.
There are many advantages to bottom watering and the overall benefit is that it promotes healthy root growth and results in healthy plant growth.
It also pays to switch things up sometimes or have a rotation schedule if you have many plants so that minerals in the water being used would not build-up to the roots and cause harm to your plant.
From our plant watering journey to yours, Happy bottom watering! We hope you found this article helpful.