Watering is a common chore for all houseplant owners- it is also one of the trickiest. Most people are familiar with the traditional way of watering, which is pouring the water on the surface of the soil allowing it to flow from top to bottom. Bottom watering (also known as reverse watering) is another watering method with its own benefits. Learn more about how to bottom water plants, how it compares to top watering, and when this method is most successful.
What is bottom watering?
Bottom watering is exactly what it sounds like- watering your plants from the bottom and letting the moisture flow up the soil. This is achieved by placing the pot in a tub of water and allowing the roots to soak up moisture absorbed through the pot’s drainage hole.
Bottom watering is suitable for potted plants with a drainage hole. Make sure the plant’s soil is not too compacted or it will be unable to absorb the water.
Find a tub or container large enough to hold the planter and fill it with water about 1 to 2 inches deep. Using filtered, room temperature water is preferable to tap water. If you have several plants that need watering, you can use a sink or bathtub to water them at the same time. If you want to fertilize your plant, mix it in now.
Then, place the pots into the water and leave them alone for 10 minutes (larger containers need more time while smaller containers need less). After that time, check the moisture level of the soil to see if enough water has been absorbed- stick a finger in the top few inches of soil. If the soil still feels dry a few inches down, keep the planter in the tub for an additional 10 minutes to soak up more water. Sandy soil or soil with a large volume of perlite takes a longer time to soak. Take out the plant once the moisture reaches just below the top soil level- soaking for too long causes root rot.
Then, drain the tub or container of water. Keep the pots in the tub so they can drain out any excess water. Do not pour this water back to the plant- if it was not soaked up, the plant does not need it.
Deciding when to bottom water your plants is similar to deciding when to top water. Push your finger into the soil. If it feels dry, it is time to bottom water. However, if the soil still feels wet, hold off on watering for a few days.
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How long should you bottom water plants?
The exact watering time depends on many factors, including: the type of plant, soil, size and type of the container, season, and how dry the plant is to begin with.
In general, smaller plants will be done faster than larger ones. Check the plant soil after 10 minutes of soaking- stick your finger in the soil and if it feels dry, allow the plant to sit for another 10 minutes.
Once the soil feels moist right below the surface, take the pots out. As you continue with this process you will gain a better idea of how long each of your plants need.
Is it better to water plants from the bottom?
Bottom watering is very effective and one of the best ways to water plants. However, this does not mean that there is anything wrong with watering from the top- it still works perfectly well.
Some pros of bottom watering include:
- Bottom watering promotes a healthier root system. Since the moisture is spread evenly throughout the soil, it allows the roots to grow stronger and deeper as they reach to cover more area.
- It is a more even method of watering. In top watering, the water often collects on top or runs down the sides of the soil, missing large areas. In bottom watering since the water is being absorbed from the drainage hole, it spreads up more evenly.
- Plants have more control over their water intake and are able to absorb what is needed. This results in a reduced risk of over watering (although it can still happen if the pot is left in the water tub for too long).
- You will not accidentally pour water on top of the leaves, avoiding any fungal infections and rot.
- The water will not stay in the top layer of the soil. Watering from the top may encourage fungi and pests. It leaves the top layer of soil moist for longer, creating a favorable environment for these pests. Keeping the top few inches of soil dry greatly helps to decrease this.
- Bottom watering ensures an even distribution of fertilizer to the all the plant’s roots.
- You do not need to worry about your drainage plate overflowing and spilling water all over the floor after you have given your plant a huge drink, creating less mess.
- Top watering causes the soil to become compact- this increases root rot since it decreases air movement around the roots.
- Bottom water is especially helpful for root bound or super dry plants (see below for more information).
When is bottom watering plants especially helpful?
Root bound plants
Some plants prefer to be root bound in their containers. Since the roots are occupying the majority of the space, watering from the top may not result in all the roots gaining enough moisture. Instead, water may run down the sides of the plant, leaving many roots dry.
However, watering from the bottom exposes the roots to moisture in a more even way. This method ensures even the tiny root hairs concentrated at the bottom of the pot receive water.
Super dry plants
For plants that are very dry, bottom watering is a great way to moisten the entire soil evenly and provide your plant with a good drink.
In addition, if you have soil that has stopped absorbing liquid poured on it (called hydrophobic soil), bottom watering can help rehydrate it.
Plants that are sensitive to their leaves being wet
If leaves remain wet for too long, it may lead to root rot or fungal infections. Some plants are especially sensitive to wet foliage, and bottom watering avoids this risk. When top watering, it is hard to avoid splashes, even if you are very careful. If you have hard water, it can cause unsightly spots on the foliage where it spills.
In particular, African violets, certain succulents, spider plants, Pothos, and Ficus are examples of plants preferring to be bottom watered.
Seedlings
Bottom watering is an effective method for watering seedlings. It prevents them from being damaged by streams of water and promotes root growth.
Should I only bottom water my plants?
There are a few downsides to bottom watering despite its many benefits.
Keep in mind, bottom watering plants does not wash away salt or mineral deposits that have accumulated on the top of the soil. This buildup can damage your plants, preventing them from absorbing the required water. To flush out these extra collected minerals, pour water over the top of the soil until it drains out of the drainage hole once every month.
Some other cons of bottom watering are:
- It is more time-consuming. Note: for a quicker way to bottom water- fill the plant’s saucer with water. Wait for 10 minutes for the saucer to empty. If the plant drinks it up completely, fill the saucer up with water again.
- If you have a very large collection of plants, they may not all fit in your bathtub at once, requiring a larger volume of water and a lengthier process.
- It does not flush out the salts and minerals that build up in the soil.
- It is easy to forget about the plants and leave them in for longer than needed- resulting in over watering.
- Larger plants take a long time to absorb water this way. It can also be difficult to constantly move plants around depending on their size and shape.
Can you bottom water all plants?
Yes, any plant potted in a container with a drainage hole can be bottom watered. However, for very large plants, this method can be quite time-consuming and not always possible. It works best for small to medium-sized plants that can be easily moved.
How to fertilize when bottom watering
Fertilizing during a plant’s growing season provides necessary nutrients and promotes optimal growth. To fertilize your plant when bottom watering, simply mix in the fertilizer in the tub of water once a month and let the plant soak it up.
In summary for should you bottom water plants…
Bottom watering works best for small to medium sized plants that can be easily lifted. For plants that are too heavy, or too tall, it may not be the best method. As long as your pot has a drainage hole, you can bottom water it.
Both bottom and top watering have their own pros and cons. Bottom watering is especially useful for dehydrated or root bound plants, or those with sensitive foliage.
Regardless of the watering method you choose, the most important thing to remember is to not let your plants sit in water for too long.
Have any additional questions about bottom watering your plants? Let me know in the comments below?
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