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How Long to Bottom Water Plants: The Things to Look Out for

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Bottom watering is a sure way to prevent overwatering and the problems that come with it but you can also overwater when bottom watering if you don’t remove the plant in time.

When managing your plants at home it is important that the soil is aerated and with good drainage, as well as favoring the water retention capacity so that the plant can take advantage of all the nutrients for its development.

In this article, we will explain what is the best time for bottom watering and the things that affect how long plants should be bottom watered.

What is Bottom Watering?

Bottom watering is done by placing the plant in a tray of water at approximately 1 to 2 inches high. The water is then absorbed into the soil from the bottom up after which it is allowed to drain freely leaving the soil moist and aerated.

The soil should remain moist for 3 to four days before it can be bottom watered again.

Bottom watering plants infographic

How Long to Bottom Water Plants?

Bottom watering should not take more than 20 minutes. A time frame between 15 -20 minutes is usually more than enough time for the soil to absorb the required amount of water to make the surface of the soil feel moist to the touch at the top.

The bottom watering method relies solely on the soil’s ability to absorb water from the bottom which is then distributed through the entire mass of the soil.

The length of time to leave a plan in a bottom watering tray will be determined by testing the soil either manually (by hand) or by use of a moisture meter. (we recommend the best one later in this post).

The time it takes for the bottom watering process to be completed also will depend on the type of soil in the plant pot.

Although many times the soil is generally potting mix, the age of the mix and how much it is compacted or settled in the pot will also determine the rate of capillary movement of water upwards into the soil.

The bottom watering process

See our detailed article on bottom watering.

Interested in bottom watering trays? I have found durable trays which worked well for all my plants. You can click here to see them on amazon.

10 Plant Growing Trays

When to Remove the Plant from the Tray?

Remove your plant from the tray after 15 to 20 minutes. This is generally enough time for the capillary movement of water through the soil to be exhausted, meaning that the soil cannot hold any more water.

However, It’s really important that you don’t let your roots sit in water for too long.

when the plant is removed from the tray, empty the unabsorbed water from the tray and place the plant back into the empty tray.

This allows any excess water to drain back into the tray which is good because you don’t want too much water holding in the soil for too long. This maintains healthy roots.

How to Determine Soil Moisture

Finger Test Method

Finger test method

When potted plants are watered, the key is in the moment. Press your finger into the soil between the wall of the container and the stem of the plant.

If you push down on the second finger joint and you still do not feel moist soil, it is time to water the plant.

Find a container large enough to hold the pot and fill it up to 1-2 inches high with distilled or filtered water. Tap water often has too much chlorine, which can damage the plants.

Place the pot in the container and leave it alone for 10 minutes.

Check the humidity level in the container again to see if the substrate has absorbed enough water.

If it’s still dry below the surface, keep the pot in the water for up to 10 more minutes to allow it to absorb as much water as possible. Remove excess water.

Bottom-watered plants keep the roots evenly moist, but they do not remove the salt and mineral deposits that build up on top of the soil after a while.

Stick Method

Stick testing method
  • Insert the wooden stick into the ground as far as you can. Be careful with the roots.
  • Leave the stick on the ground for 5 minutes. This will give the stick time to absorb the water from the soil.
  • Remove the stick. If the stick has a watermark or dirt stuck to it, the substrate is wet. If it is dry then there is no color change then you should bottom water the plant.
  • Sanitize up the stick and let it dry to reuse it next time.

Soil Moisture Meter

Soil Moisture Meter is an easy-to-use and accurate device for detecting soil moisture. The soil moisture meter shows you the current moisture in absolute percentage as well as the wilting point or the degree of saturation of the soil or soil.

The simplest meters are a type of hygrometer and have humidity sensors to measure soil moisture levels.

Often showing the humidity level on a color-coded scale from 1 to 10, a decimal number or a percentage value where lower numbers indicate drier soil and higher numbers indicate wet soil.

Best Moisture Meter for Measuring Soil Moisture:

XLUX Soil Moisture Meter

XLUX Soil Moisture Meter is an excellent and pocket-friendly moisture meter to know when exactly your plants need water. 

With XLUX Soil Moisture, all you need to do is stick it in your potting soil or garden soil, wait a few seconds and read the gauge to know how moist the soil is. That’s all.   

Knowing the moisture level of your soil will save you from problems like overwatering and underwatering. 

VIVOSUN Soil Tester:

With VIVOSUN Soil Tester, you can not only test the moisture level of your soil but can also control pH level and determine whether your plant is getting enough sunlight or not. 

This 3-in-1 Plant moisture sensor meter is also pocket-friendly and easy to use.

How does Soil Type Affect Watering Time?

A good Soil enriched with minerals ensures the best growth and also retains moisture better and more evenly.

In rainy summers and winters, this soil provides good drainage, avoiding waterlogging.

Sandy Soils

Loam Soil

Sandy or sandy loam soil is characterized by the presence of a large number of voids between soil particles.

Because of them, the number of capillaries in the soil is reduced, and gravitational forces prevail, under the influence of which the lateral distribution of moisture decreases and its outflow downward is observed.

Clay Soil

Characteristics of Clay Soil

Clay soil has a larger number of capillaries, which cause the movement of water to the right and left outside the distribution point.

At the same time, the gravitational indicators, leading moisture downward, are reduced. Water permeability in such soil is low, moisture remains for a long time in the root zone.

In clay soils that have been compacted, the downward outflow of moisture is even more limited.

Excessive watering on such soils can lead to stagnation of water in them and inhibition of the root system of plants.

Loam Soil

Characteristics of Sandy Soil

The most optimal characteristics of capillary movement in medium-heavy soils better known as Loam soil.

Loam soil is composed of almost equal amounts of sand and silt with a little less clay. A good ratio is 40 percent of sand and silt, and 20 percent of clay.

Best Timer for measuring time

There may be times that you may forget that you are bottom watering your plant and may need a gentle reminder.

A timer may be important in order for you not to overdo that bottom watering process. It helps to prevent overwatering from bottom watering and suffocating the plant and presenting unwanted diseases like root rot.

The best timer we have found on amazon is the Colortrak 60 Minute Wind Up Timer.

  • It is Easy To Operate,
  • Set for Short Time,
  • Sets From 0 to 60 Minutes,

The Takeaway

– Bottom watering is done by placing a container under the pot and filling it up with water until it reaches the rim of the pot.

– Bottom watering should take anywhere between 15 to 20 minutes.

– Bottom watering is best suited for plants in smaller pots up to 12 inches in diameter.

– You must wait for the soil to fully absorb the water before you remove the container.

– The time it takes to complete the bottom watering process depends on the type, age, and how compacted the soil may be.

It may become necessary to purge the soil and remove excess minerals from it, it should be water from the top once a month. Pour water over the top of the soil until the bottom drains.

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