Updated at: 20-09-2022 - By: Sienna Lewis

A greenhouse’s irrigation and ebb and flow systems are critical to understanding how water reaches plants. Because water is a limited ingredient in photosynthesis, if you don’t supply your plants with enough of it, their development and health will suffer. The greenhouse’s ability to provide limitless support for your plants relies heavily on the presence of water.

A wide range of factors can affect how much water you use in the greenhouse. There may be rules and regulations to consider based on where you live. According to a report from the University of Massachusetts Amherst, greenhouse owners should also keep in mind the possibility of drought conditions.

Regardless, this article should provide you with a basic understanding of how water is delivered to your greenhouse plants. You may then use this information as a reference to better organize your greenhouse and have a productive garden without problems with irrigation.

How Does Water Get To Plants In A Greenhouse: Two Common Ways

Irrigation systems

Irrigation systems are the most prevalent means of obtaining water in a greenhouse. Drippy irrigation is one type, while water trays or saucers are another, and there is no runoff or sub-irrigation in between. What is the finest irrigation system for a greenhouse, assuming you must make such a decision?

Greenhouses contend with the climate to keep plants growing

You may control the amount of water you apply with drip and sub-irrigation systems recommended by the Center for Agriculture, Food and the Environment at UMass.

Drip vs subirrigation

When opposed to using overhead sprinklers or incorrect hand watering, these solutions avoid damp foliage that can lead to illness and damage. Overhead sprinkler systems, on the other hand, deliver only 20% of the water they’re supposed to to the soil. An in-pot drip system will ensure that all of the water is delivered to the soil.

Use a timer and flow gauge to make sure your plants are getting the right quantity of moisture. Isn’t sub-irrigation an option? In place of hand-watering, sub-irrigation can be as basic as capillary matting.

You may place them under your plant pots, which have holes in the bottom that allow water to flow back to the roots. Overwatering can be alleviated with this idea, as can rot, which is a typical cause of fungal disease.

Ebb and flood systems

Ebb and flood systems are an efficient method of conserving water and delivering it to greenhouse plants. When a table has an intake for water, the water might flow at a lower rate than the fill rate. As a result, the water can be channeled to the drainage system, where it can be used to irrigate additional drip lines in the greenhouse.

Ebb and flood systems can alternatively be referred to as “ebb and flow” or “flood and drain,” and these terms are interchangeable. Let the water flow to your growth areas and let it drain back to the reservoir is the simple notion. A flood is called a flow because of this.

What To Consider When Watering In The Greenhouse


The greenhouse’s watering schedule will be determined by the time of year, temperature, and amount of light. Compared to rainy and foggy days, hotter days can dry out the soil more quickly. This is why, in cold and wet weather, it’s best to water during the day so that the plants remain dry at night and mildew doesn’t form.

Adding more water to the plants’ needs is a smart idea when the sun is out for long periods of time. In fact, in the winter, you may not even need to water or irrigate your plants.

When to water

It’s critical to avoid over- and under-watering, regardless of the time of year. As soon as you see that the medium surface is lighter than normal, you know it’s time to water. If the soil or medium crumbles or feels dry when you squeeze it, that’s a good sign that it’s ready for planting.

How much water is need

If a plant isn’t getting enough water, it’s going to reveal its dehydration symptoms. You can also avoid flooding the medium by applying little amounts of water periodically in the greenhouse. It is also customary to saturate the medium with water and then let it do the rest.

Both methods necessitate that the medium dry out completely between waterings. It’s important to keep in mind that some plants will dry up faster than others, so keep an eye out for any signs of overwatering.

How is Greenhouse Watering Different From Outdoors?

When you cultivate veggies or other plants in a greenhouse, you’re able to provide them with more personalized attention. Having all of the plants in the same place allows you to better handle their needs than if they were spread out across the landscape.

However, there is a price to pay for having more power. Because they are effectively being grown indoors, your plants do not have access to natural rainfall.

Your first reaction may be to dismiss this as a nonissue. As if planting a container garden indoors was any different, right?

Gardening indoors and in a greenhouse are two different things. Crops cultivated in greenhouses, like those grown indoors, lack access to rain. The only difference is that they are kept at a significantly higher temperature than plants produced indoors. Even if they aren’t subject to the drying effects of wind, plants grown inside receive a great deal of heat and light.

Keeping your plants in a greenhouse means they’ll dry out more quickly.

How Often Should You Water Plants in a Greenhouse?

When it comes to watering a greenhouse plant, it’s important to consider the type of plant you’re growing, as well as the climate outside.

Too much watering might promote root rot in your plants, so avoid doing it as much as possible. When the first few inches of soil are dry, only water. Unless you’re watering seedlings, avoid watering shallowly. In a short period of time, the earth will become extremely dry.

In general, deep, thorough watering is preferable. Depending on the crop, you may be able to get away with watering every other day or only a few times a week if you’re planting in the spring or fall (or even winter). During the hottest months of the year, it may be required to water the plants daily or even twice a day.

What is the Best Time to Water a Greenhouse?

As with plants in the yard, the optimum time to water a greenhouse is first thing in the morning. The plants will have time to dry out. In order to prevent evaporation, you can water your plants in the evening. However, this may mean that your plants aren’t completely dry before the sun sets.

How to Keep Plants Watered Without Damaging Them?

If you’re growing plants in a greenhouse, one of the finest advice is to avoid using water that is too cold. In this respect, plants and people are very similar. Think about it: Do you enjoy taking a shower at 50 degrees Fahrenheit?

When you use really cold water on plants, they can also get spooked. In order to control the temperature of the water, a plate heat exchanger may be an option for you. Your plants will be shocked if you use water that is too chilly. It can also wreak havoc with the delicate ecosystem of microorganisms that feeds your plants.

How Does Water Get To Plants In A Greenhouse - Krostrade

When watering your plants, you may also wish to use a more gentle misting nozzle. For germination or the establishment of new seedlings, sprinkle the soil with a fine mist. It’s unlikely that your plants can withstand a strong burst of water because their roots aren’t fully developed. You should not spray them at maximum intensity even if they do.

Hanging hooks may be necessary if your greenhouse watering is done by hand and you don’t use drip lines or overhead irrigation. While standing at the door of your greenhouse, you will be unable to reach all of your plants.

A hose running across the entire greenhouse is a tripping hazard, and it increases the risk of crushing your delicate plants in the process.

Additionally, it’s just a nuisance to deal with!

How to Water a Greenhouse While on Holiday?

Plants grown in greenhouses are more prone to drying up and dying from lack of water than those cultivated in a garden because of the absence of sunlight. For a trip, you’ll need to be more aware of the flora in this environment.

It may be possible to lower the temperature by wetting the ground and then mulching it. Consider installing some shade netting to keep your plants from overheating.

If you’re planning a vacation, a drip irrigation system on a timer is a smart option for watering your plants.

How often should I water my plants in the greenhouse?

  • You’ll have to factor in the specific requirements of the plants you intend to grow.
  • As long as the greenhouse does not get too hot, it is necessary to water the herbs every few days.
  • When the weather is hot and sunny, container plants need to be watered frequently. Mature bushes, on the other hand, may only require watering in times of extreme drought.
  • Wait until the first few inches of soil are dry before watering.

How to water greenhouse plants?

  • Water and hosepipe limitations come into effect when the weather is hot and sunny in the summer.
  • Both fungi, such as mildew, and insects, such as slugs, are discouraged by morning watering of plants.
  • Watering in the morning causes the compost and plants to dry out faster. Even in the midst of sweltering temperatures, it is possible to overwater plants.
  • Plants with leaf adaptations, such as silvery leaves, should be checked out first. As a result, they won’t need to be watered as frequently.
  • Look for signs of withering or swelling on any of the plants. Yes, they will require watering.
  • In addition, if the compost dries out, it means the plant needs water.
  • Avoid getting the leaves of a greenhouse plant wet when watering it at the roots.
  • Keeping a plant well-watered reduces the frequency with which it has to be watered.
  • Give plants 10% of their container volume in water (for example, 12 Lt for a 5 Lt container).
  • Slowly pour the water into the compost rather than letting the water go over the top of the pot, so that the compost can absorb the water.
  • Serve as a reservoir for the plant’s absorption by placing saucers underneath containers.
  • Drying the compost between waterings is preferable to keeping it damp and spongy.

Seven factors that affect water usage in a greenhouse

A greenhouse’s water usage might be affected in one of seven different ways.

1. Solar radiation.

In greenhouses, the rate of transpiration is lowered, resulting in a 40% reduction in the amount of radiation that reaches the plants.

2. Shading.

Reduced radiation levels can be achieved by covering both the greenhouse’s inside and exterior with a layer of shady material.

The evapotranspiration of moisture and the water requirements of plants both reduce when shade is supplied.

3. Air movement.

Fan ventilation and horizontal airflow systems increase evapotranspiration.

Up to 20% of evapotranspiration can be boosted by a breeze of five mph or less.

Evapotranspiration can be influenced by the greenhouse’s location.

4. Size and types of plants.

Compared to a fully established crop, little potted plants and seedlings use less water. Heavy leaf canopy plants, on the other hand, necessitate more water.

5. Types of irrigation systems.

An overhead sprinkler system delivers only 20% of the water to a potted plant crop with a lot of leaves.

In hydroponics and flooded flooring, excess water is reused or recycled, hence conserving water.

6. Leaching.

It is advised that at least 10% of the water sprayed to greenhouse plants be allowed to be drained out of the plants. Increased water use is caused by the removal of fertilizer salts through leaching.

The amount of water a plant can hold and how often it has to be watered are both influenced by the growing medium.

7. Other factors that affect water usage.

Water is also utilized for pesticide application, evaporative cooling, and clean-up in addition to plant demands.

How Often To Water Plants in Greenhouse? & Techniques

Eight questions about greenhouse plants and water usage

1. How often should I mist my greenhouse?

One to fourteen times a day is a common setting for electronic timers in most misting systems. The duration of a misting session might vary from a few seconds to up to twenty-four hours. Shorter but more frequent spraying can be achieved with some misting systems. Brass or plastic are the most common materials used to construct misting system nozzles.

2. What is the best time to water a greenhouse?

Watering a greenhouse plant early dawn is ideal since it gives the plants time to dry out before the next watering.

Evaporation will be reduced if you water your plants in the evening. However, if you water your plants in the late afternoon, they won’t be completely dry by the time the sun sets.

3. How much water does a greenhouse use?

On a hot day, a greenhouse’s peak water demand is between 0.3 and 0.4 gallons per square foot.

A greenhouse with a bench area of 2400 square feet, for example, would have a maximum daily water consumption of 720-960 gallons.

4. How long can plants go without water in a greenhouse?

The majority of houseplants can go two to three weeks without water.

You should be aware that the amount of water your plants require will vary based on their variety and the weather.

5. What are the most reliable methods of watering greenhouse plants?

  • Drip tubing is the best irrigation method for medium-sized structures, such as hobby greenhouses.
  • Each potted plant should have a drip tube inserted into it and connected to the main water supply.
  • Turn on the main water supply and fill the tubes when the plants require watering.
  • Spraying the pot’s dirt is done when the tubes are full.

6. Do plants grow faster in a greenhouse?

There are two reasons why plants in a greenhouse grow quicker than those outside.

  • Greenhouses allow you to manage the temperature of the environment.
  • In addition, a greenhouse’s carbon dioxide concentration is higher than that found in nature.

As a result, greenhouse plants develop more quickly because of these two variables.

7. Should I water my greenhouse every day?

  • Every plant has varied demands, thus there is no rule dictating how often it must be watered in a greenhouse.
  • Some plants may require daily watering, while others may not need it at all.
  • Please conduct some study on the water requirements of the plant you intend to grow. The only way you can go wrong is if you do this.

8. Why are my plants wilting in the greenhouse?

  • Leaf wilting or yellowing can occur due to a lack of sunlight or plant disease.
  • Plants will wilt if the greenhouse is exposed to the sun for long periods of time and watering schedules are not followed.
  • Inadequate drainage and excessive fertilization can lead to wilting in greenhouse plants.
  • If a greenhouse plant isn’t getting enough light, it will wilt.
  • Plants will wilt if they receive too much water.
  • Insufficient drainage causes wilting in overfed plants.

Professional Greenhouse Watering Tips

When it comes to watering your greenhouse, there are a few pointers to keep in mind. As a first step, you’ll need to determine whether you like automated or manual watering.

Be sure to keep in mind the specific requirements of your plants. Drip irrigation in greenhouses is effective. Using a flow meter and a timer, you may control how much water your plants receive. This is a low-cost and simple-to-maintain option.

For greenhouses with a wide variety of plants, overhead watering is a great option. There are a variety of capillary mats that can be used in place of flats and pots as well. They use a technique called sub-irrigation to carefully move water through the system. As a result, the evaporation rate is reduced and the risk of overwatering is reduced.

1. Group Plants with Similar Water Requirements Together

If you’re going to be growing a variety of plants in the same greenhouse, it’s best to group plants with comparable watering requirements together. Cucumbers, on the other hand, should be planted separately from peppers and tomatoes.

So even if you’re hand-watering, you can better tailor your approach and avoid over- or under-watering the entire garden.

2. Mind Your Spacing

Even in a greenhouse, the importance of proper spacing cannot be overstated. With little room to maneuver, watering plants that are tightly packed in a greenhouse will be difficult, and you run the risk of accidentally pulling one out of the ground with your hose.

In addition, because of the reduced air circulation in a greenhouse, plants that are packed too closely together are more likely to contract fungus illnesses.

3. Overhead Watering Systems for Greenhouses

In a greenhouse, overhead watering methods might be costly. The work is worthwhile, however. Watering your plants will be easier to schedule, and you’ll have more control over how much water they receive.

It’s inefficient to use an overhead watering system if you have a variety of plants with various watering requirements. The needs of each plant will have to be taken into consideration. As a result, you’ll have more control over how often and how long you need to irrigate.

While some plants may be over-watered, others may be under-watered, due to overhead irrigation. If you have a wide variety of plants in your greenhouse, you may want to explore hand-watering.

4. Watch for Excessive Moisture

Plants do need to be well-watered, but too much moisture might harm them. Wet soil is not ideal for plants. Fungal illnesses can be caused by excess moisture in the greenhouse. Fungal diseases are just as prevalent in greenhouses as they are in the field. This is because there isn’t enough air movement.

Consequently, you’ll have to keep an eye on how quickly your plants are drying out. Install ventilation systems if at all practicable. In this way, you won’t have to worry about your plants becoming infected by fungal disease.

On cloudy days, remember that your plants’ water requirements are significantly lower than on sunny ones. On a rainy or overcast day, you may find that you don’t need to water as frequently.

5. Install a Collection Tank

Installing an outside collection tank may be an option if you live in a dry climate. Allows you to save and reuse rainwater for your greenhouse’s watering needs In many cases, these can be connected to the greenhouse’s drip or overhead irrigation systems.

Make sure to keep these ideas in mind when you’re designing your new greenhouse. Your plants will be happy and healthy thanks to our mistakes, and you won’t have to go through the same agonizing process yourself.

Final thoughts on – do greenhouse plants need more water?

  • Plants in greenhouses might consume less water if they are properly cared for.
  • The gardener has more control over water use in a greenhouse because it is a controlled environment.
  • An irrigation system for the greenhouse might help you save water.
  • Don’t forget that overwatering and excessive moisture can cause fungal illnesses and create an environment where some pests can flourish.
  • Water-demanding plants should be kept together.
  • If you have a variety of plants in your greenhouse, avoid using an overhead watering system. Instead, you can save money on water expenditures by putting up a tank to collect water that has already been used.
  • Use a drip irrigation system for tiny and hobby greenhouses. Each day, drip systems deliver the exact amount of water that is needed, regardless of the season.
  • Not all plants demand equal amounts of moisture.