Bottom Watering Seedlings: A Complete Guide

A fantastic approach to make sure seedlings are receiving the necessary amount of water to grow healthily is to bottom water them. Because you can overwater once done correctly, it eliminates the guesswork in determining how much to water.

By enabling the entire root system to utilize the applied water that has been evenly dispersed throughout the soil, bottom-watering seedlings encourage vigorous and healthy plant growth. The prevention of overwatering and the accompanying pests and diseases is another advantage of bottom watering seedlings.

Watering seedlings from the bottom can be challenging, but it is well worth the trouble. Water is necessary for seedlings to flourish, yet improper watering might eventually cause them to perish.

You may learn how to water your seedlings effectively so that they have the best chance of surviving and developing by reading this article.

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What is Bottom Watering?

The practice of watering plants and seedlings from the base of the plant is known as bottom watering. Because water can be supplied directly to plants with minimum waste, bottom watering is a simple and economical method of growing plants.

When seedlings are irrigated from the bottom, capillary action causes the water to move upward through the soil.

In order to provide all the roots with an equal amount of water, the water is then able to distribute equally throughout the soil structure of the seedlings.

Water is prevented from accumulating in one spot for an extended period of time by gravity.

Any extra water that was hung up is then allowed to freely drain away from the soil after being removed from the bottom watering tray, leaving only the water that the soil has absorbed during the watering interval.

In addition to avoiding overwatering, this method of watering avoids giving the plant an excessive amount of moisture.

The roots of seedlings can rot due to an excessive amount of water. A simple solution to this issue is to water from the bottom.

How to Bottom Water Seedlings?

In order to avoid the negative effects of overwatering, bottom watering requires a little bit more time than traditional top watering.

In light of this, seedlings are at a particularly vulnerable point in their life cycles, and any kind of stress might result in unintended catastrophe.

This is why we advise bottom watering and have provided a step-by-step tutorial on how to do it properly so that your seedlings grow into strong, healthy plants.

Steps for Bottom watering seedlings –

  1. A flat, open tray that is bigger than the seedling tray should be obtained.
  2. Set your seedling tray on the open, flat surface of the container for bottom irrigation.
  3. 1 inch of water should be put in the container.
  4. Get rid of the seedling tray after 15 to 20 minutes.
  5. From the flat container, drain any extra water.
  6. After 10 minutes, put the seedling tray back into the empty container and let any remaining water drain out.
  7. Take away the planter tray

Note: The amount of time needed to bottom water the plant should be sufficient to allow the water to reach the soil’s surface. When the top of the soil feels damp to the touch, the bottom watering operation is finished.

What to Look out for

Depending on the proportion of organics and additions in the soil, different types of soil mixes would absorb water and nutrients at varying rates.

You should check the seedling soil to evaluate how well it would absorb water because different plant species would have different soil needs. But that is only a visual.

The best test would be to use the bottom watering technique and track how quickly or effectively the soil absorbs water. By doing so, you can estimate how long the seedlings should be kept in the watering tray.

The Benefits of Bottom Watering Seedlings

Bottom watering seedlings has the general advantage of ensuring that they leave this fragile stage as healthily as possible.

Additional advantages of bottom-watering seedlings include:

Promotes Healthy Root and Plant Growth

The roots of the seedlings spread more uniformly throughout the structure as a result of the water being applied to the bottom of the soil system.

When this occurs, the seedling’s roots will have easier access to more nutrients in the surrounding soil.

This ultimately results in a seedling plant that is more robust and healthy. When they are mature enough, putting them in an open garden area significantly improves their chance of survival.

Prevents Overwatering

Bottom watering solely uses capillary movement to apply the necessary amount of water to the soil, as was previously discussed.

The extra water is washed away by gravity after the soil absorbs what it requires. The soil around the seedling roots can now be used to absorb nutrients and water.

Prevents Root Rot

As you may know, overwatering situations, where all the air spaces between the soil are filled to the brim with water, are what cause root rot.

This extra water suffocates the plant’s roots with oxygen. Dark brown to black roots are indicative of root rot since there isn’t enough oxygen present.

Plants become weaker, yellow and stunted; they may also wilt or die back and lose some leaves. Both water and fertilizer have no effect on them.

Bottom watering addresses this issue by giving just the right amount of water.

Prevents Pest and Fungus Growth

Bottom watering seedlings slows the environment that would typically favor the growth of fungi and pests like fungus gnats by minimizing excessively wet and overwatered circumstances.

When fungi are in good health, they draw the tiny, fungus-eating gnats that resemble flies. The gnats enjoy moist environments as well, and they will eat the seedlings’ roots until they die.

Regulates Humidity

When seedlings are watered from the bottom, there is less moisture around the plant, but it is the ideal amount for the plant to thrive.

A moisture-loving fungus may establish itself as a result of high humidity, which will negatively impact the health and growth of the seedlings.

Bottom Watering Vs Top Watering

Top watering fosters the growth of fungus and gnats while the water might be diverted out of the soil, not being able to reach the complete root system. Bottom watering plants keep the soil consistently moist so the entire root structure receives water.

According to experts, a garden should receive around one inch of water every seven days, and strong soil structure is essential for plants to successfully absorb water.

Ground WateringBest Watering
Stop overwatering.fails to stop overwatering
The soil receives uniform water application.You can channel water (not reaching all the roots)
can aid with humidity management.does not significantly reduce humidity
stops soil from spilling aroundcan lead to soil splashing
prevents the infestation of pests and fungican spray water on leaves to prevent the growth of fungus
prevents the occurrence of root rotcan result in root rot if overwatered

When to Bottom Water Seedlings?

It will be wise to think about the time of day to administer water from the bottom while bottom-watering seedlings.

The optimum times of day to bottom-water your seedlings are in the early morning between 6 and 9 am and in the late evening between 5 and 6 pm.

This is because less water is lost to the atmosphere over time at this time due to reduced humidity levels in the air and surrounding area.

For seedlings that did not germinate under a humidity dome, these advised times are given.

Although using a humidity dome for seedlings is a common practice, it is not necessary. The seeds will still grow into plants.

A humidity dome, on the other hand, increases the rate of germination while keeping the soil moist for a longer period of time.

With this exception, bottom watering can be carried out at any time of day while employing a humidity dome.

How often to Bottom Water Seedlings?

When the ambient humidity is higher, such as in the morning or the evening, seedlings can be bottom-watered once per day.

However, how dry the growing media is is the best sign that your seeds or seedlings need water. The dirt shouldn’t feel too wet or too dry when you touch it. It should feel more like a wet sponge.

You can water the seedlings again the same day if you watered them in the morning and discovered that the soil was dry.

Keep the soil moist is the general rule.

As previously said, using a humidity dome helps minimize the issue of the soil drying out too rapidly by prolonging the humidity in the area around the seedling.

Best water for seedlings when Bottom Watering?

Distilled water or rainwater work best for seedlings.

Since all the minerals have been boiled out of distillate water, it is essentially the purest type of water. After the steam condenses and turns into condensation, the clean water is collected in a flask.

The best form of water you can give your plants is rain, without a doubt. Your plants will grow bigger and healthier with this water than with any other because it is rich in minerals that are essential for plant growth.

A pH of 5 to 5.5 describes how mildly acidic rainwater also is. Due to the soil’s ability to mobilize nutrients quickly as a result of this little acidity, seedlings will receive more nutrients more quickly, which will result in faster growth.

The quality of the water in your location will determine if you should use tap water as an alternative.

The majority of tap water should be suitable for your indoor plants, unless it has been softened. This is because salts in tap water can accumulate in the soil over time and eventually lead to issues.

Most houseplants can utilize chlorinated water without harm, but if you have a filtering system, your plants can benefit even more.

Applying fertilizer when bottom watering

Depending on the plant variety and the required nutrients, seedlings may need to be nourished.

The seedling can more effectively absorb the nutrients that are applied if fertilizer is added when bottom watering since the entire root system will have access to the fertilizer’s nutrients.

This method of applying fertilizer necessitates the use of a water-soluble fertilizer. Before adding the fertilizer to the watering tray, it is first completely dissolved in the water.

The same watering time is then followed using the aforementioned technique.

To learn how to bottom water with fertilizer, see our more in-depth post.

The Takeaway

Your seedlings will benefit most from bottom watering.

Without putting them at risk from bacterial or fungal growth, it gives them the constant supply of nutrients and water they require as their roots grow.

Bottom watering has many advantages over the more common top watering technique. One of them is the virtually impossible possibility of overwatering your seedling, which can encourage the growth of numerous pests and diseases.

You now possess all the knowledge necessary to successfully transplant your seedlings into your garden, including when, how frequently, and how to add fertilizer.


Do you water seeds from the top or bottom?


Should you bottom water seeds?

By enabling the entire root system to utilize the applied water that has been evenly dispersed throughout the soil, bottom watering seedlings encourage vigorous and healthy plant growth. The prevention of overwatering and the accompanying pests and diseases is another advantage of bottom watering seedlings.

How do you water the bottom of a seedling?

How often should you water a seedling tray?

Because seedlings can’t hold water for very long, they require consistently moist soil. Depending on how rapidly they dry out, this calls for watering them several times per day. With the tip of your finger, probe the soil of your seedlings down approximately an inch. Water is required by your seedling if the soil is dry.