How to Correctly Mist Plants: Misting and Humidity Explained


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Misting is the act of temporarily increasing the humidity around a plant by applying water in the form of tiny droplets from spray bottles or canisters.

Mist should be applied both to the top and underside of plant leaves during early mornings between 7 am and 9 am and on evenings after 5pm. This is because during these times the stomata are open which allows water to readily absorb into the plant. 

When it comes to misting, having an understanding of what misting does and how plants use the fine water droplets, will help us provide the right conditions for our plants.

Plants actually use only a very small amount of the applied water for the transport of nutrients and minerals and also photosynthesis. 

The rest of the water (approximately 95%) is lost through transpiration via the stomata on the underside of the leaf.

Most tropical plants hold water in their leaves and misting acts like a direct and easy top-up when water is needed.

The Science Behind Misting

Transpiration

The leaf of the plant contains various openings, plant cells and transport systems. They all work together in producing and transporting food for the plant to maintain healthy growth.

Misting can provide benefits such as cooling, plant hydration through humidity, and soil hydration. Cooling occurs similarly to when the plant leaves sweat. See our article on what causes plant leaves to sweat.. Cooling occurs similarly to when plant leaves sweat. See our article on what causes plant leaves to sweat..

We are going to explain the science behind these cool misting facts and how they benefit your plants.

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Cooling

The water provides an avenue for the plant to get some degree of cooling as the water evaporates from the surface of the leaf. 

Cooling occurs as the water changes state from a liquid to a vapor. In order to do this the water molecules require energy (heat) which is absorbed from the surface of the leaf, hence cooling the leaf as it evaporates.

This cooling effect is extended to the entire plant via the movement of fluids in the xylem and phloem throughout the plant.

Therefore misting is very important during hot days in order to reduce plant stress caused by heat.

Increases Humidity

Misting increases the humidity around the plant. Although some argue that this is for a short period of time. The overall effect of humidity around a plant is to allow water to be absorbed by the plant.

On average tropical plants are subjected to a humidity of 88% in their natural environments, whereas the average houseplant will require a humidity that ranges somewhere between 30% and 40%. 

Additionally, indoor humidity can be affected by other factors such as seasonal conditions, wind, and appliances such as air conditions, radiators and fans.

What does humidity actually mean according to the National geographic encyclopedia?

Humidity is the amount of water vapor in the air. If there is a lot of water vapor in the air, the humidity will be high. The higher the humidity, the wetter it feels outside.

Humidity is usually explained as relative humidity. Relative humidity is the amount of water vapor actually in the air, expressed as a percentage (%) of the maximum amount of water vapor the air can hold at the same temperature.

It’s not practical to mimic the full tropical conditions for plants as such high humidity can cause mold and fungus growth within our homes which can cause health problems.

However, we can temporarily increase the humidity around the plant by misting or using a humidifier which we will explain later.

Additionally, by grouping plants together in the house you can increase the humidity around the plants themselves. 

This is because as plants transpire the lost water that enters the air will increase the humidity which can be beneficial for other plants in close proximity. 

Increases Soil Moisture 

An experiment done by The National Center for Biotechnology Information showed that when the humidity of the surroundings is high the water-absorbing abilities of the plant is primarily done by the leaves which are transported to the soil. 

As a result, it directly increases the moisture content of the soil in which the plants were planted. This is shown in the following table.

Soil TypeMoisture Equivalent % moisture after 24 Hours% moisture after 48 Hours
Light Soil12.518.520.2
Medium Soil22.725.027.0
Heavy Soil36.839.547.2

If you are interested in how to better manage your soil moisture, We have done a well researched article on this topic here

Misting the Underside of the Leaf is Important

Water is required for plants for the process of photosynthesis, which is the method by which plants make their food.

When we mist, we often spray the plants on the top of the leaves. This misting action only allows the water to coat the surface. 

misting can amazon

On the underside of leaves, unveils a new dimension when it comes to plants and how fluids and gases are exchanged. This is facilitated by small openings called the stomata.

The stomata opens and closes with the aid of guard cells, to allow water and carbon dioxide in and out of the leaf depending on how much it needs. 

For this reason, it is recommended, in addition to misting the top, that misting the underside of the leaf will help the plant in absorbing the moisture it needs more efficiently.

Plant Care

Should you Mist the Soil?

Misting the soil will not add beneficial water to the plant as the water will not be able to reach the roots for the absorption process to take place. Therefore it should not be a practice to adopt.

The mist would merely wet the surface of the soil which would stay moist for a short period of time before the water evaporates the atmosphere.

Apart from providing water for the plant from root absorption, water in the soil is needed to help minerals dissociate or break up and dissolve. 

The dissolved minerals are then absorbed into the plant via the roots which are transported to different parts of the plant where it is needed for growth.

How do Plants Absorb Water from the Leaves?

Water is absorbed from the leaves into the plant via the stomata when the leaf-water potential is high, that is, the moisture in the air is higher than the moisture within the leaf. 

An experiment [Google Scholar] conducted in 2009 showed that – 

Leaf wetness may increase plant hydration in two ways, either by providing a direct water subsidy accessible through foliar uptake that increases tissue water content or by suppressing leaf water loss to the atmosphere and thereby facilitating more efficient foliar hydration with stem xylem water from the rooting zone.

The increase in leaf-water Differential increases the foliar water intake

Water absorption in plants (2)

Do Plants Absorb Water Faster through Roots or Leaves?

Yes! Plants will easily absorb water through the roots than the leaves. This is because the roots contain specialized hairs along their length which increases their surface area and makes absorption of water, minerals, and nutrients easy. 

However, the rate at which water is absorbed by the roots is also dependent on osmotic pressure but not as pronounced as that of the leaf and its leaf-water differential.

The absorption of water via the leaves as previously explained depends on the leaf-water differential such that the water in the leaf is less than that of the atmosphere around it.

This differential in water concentration is caused by the deficit of water both in the plant leaves and in the soil.

Therefore if you haven’t watered your houseplant for some time and it shows signs of dehydration, misting will provide a good means of water for the plant.

However, you should not wait for your plants to start showing signs of dehydration such as limp leaves or wilting before you start misting or even watering.

A more routine application of mist would prevent any detrimental effects of underwatering and would therefore save the plant’s life.

Leaf Water Absorption

Can you over mist a plant?

You cannot over mist a plant because the plant will only absorb the water that it needs.

The stomata will open to absorb the required amount of water for the plant to function properly.

Where over-misting is concerned, plants will like the additional water which will drip onto the soil where the roots will have access to it.

On the human side of things, you will have to consider the effects of the increased humidity on nearby furniture.

Over-misting will damage flooring and furniture that are not tolerant to high moisture.

Additionally, a lot of mist in one area can bring other issues such as moss, mold, and fungus on walls and surroundings.

On the contrary, if you take too long to mist your plant, you should consider watering via the soil to help speed up the water absorption process.

This is because if the plant is stressed by an extreme water deficit, as a natural reaction, the stomata will close to prevent any water loss and as a result will not react fast when foliar mist is applied.

Watering through the soil will be a faster fix to the dehydration problem and should be considered even if your plant is normally watered via misting. 

Once the plant has returned to its normal and happy state, you can resume your routine misting.

The Geniani portable humidifier from amazon provides the ideal environmental humidity for healthy plant growth. You can find it by clicking here.

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Houseplants that Should be Misted

Here is a table showing houseplants that should and shouldn’t be misted

PlantShould be MistedShould not be Misted
Orchidscorrect
Arrowhead plantcorrect
Fiddle leaf figs correct
Indoor palmscorrect
Zebra plantcorrect
Pothoscorrect
African violetcorrect
Spider plantscorrect
Peace lilycorrect
Succulentscorrect
Philodendroncorrect

On the contrary, there are some plants that should not be misted, such as those with fuzzy leaves.

Those are –

  • African violets
  • Piggyback plants (Tolmiea)

The mist can settle on top of the leaf and cause unwanted growth of mold and fungus which can damage the leaves.

Best Time to Mist Plants

Misting can be done throughout the day especially during hot days when the humidity can get very low. 

However, considering that most people may have a busy schedule and other commitments such as work or school, providing continual misting may not be feasible during the day. 

Stemming from research by which plants readily absorb fertilizer better during early mornings and late evenings. 

The best time to mist plants is

  • On mornings between 7am and 9am
  • On late evenings after 5pm
Plant on a window ledge

Placing the Plant in the right space

Bathroom

Placing the plant in the Bathroom is a great idea if you only have a few plants that can be easily moved. 

The steam from the shower will increase the humidity and provide the right conditions for the plant to survive especially during winter periods. 

The overall effect would allow for less misting where plant hydration is concerned. 

Corners or in a closed room

Having the plant in a corner of a well-lit area or even close to a window will help with water retention as the conditions will not allow for moisture to be reduced easily.

Where not to place the plant

Front doors

Having the plant situated in an area of high airflow such as close to a front door can significantly reduce humidity and its effects. 

The plant and soil will dry out quickly even if it’s misted on a routine basis. 

Radiators, heaters, Air Conditioners and fans

Radiators and heaters can significantly reduce the humidity around a plant due to the increase in temperature. 

Having plants close to these appliances will increase the rate of evapotranspiration, drying out the plant very quickly. 

Evapotranspiration is the combined effect of transpiration and evaporation. Where water or moisture is lost both through the leaves and the soil. 

Should you Mist and Water at the Same Time?

Misting and watering at the same time should be done at least once a week.

Here’s why –

Misting is one way to rehydrate plants and should be done routinely to ensure the plant does not suffer from dehydration. 

Watering the soil, however, directly adds water to the roots which can absorb both the water and dissolved nutrients from the soil. 

Soil watering is done less frequently and allows water to hold for some time within the soil. The plants can take up the water they require over a longer period of time. 

Therefore less attention is needed when only applying water to the soil. 

An application of water once a week to the soil and once or even twice daily via foliar means will provide the plant with all the hydration it needs. 

Additionally, daily attention to the plants while misting will create a closer bond between you and your plant and can also help with early detection of pests and nutrient deficiencies. 

Cross Section of a Root (3)

Misting vs Soil Watering

MistingSoil watering
Has to be done more frequently Can be done once a week
Fast absorption from the leavesAllows nutrients to be absorbed from the soil
More attention is needed
detection
Less attention is required  
Can help in early pestLess attention means later pest detection
Over misting can cause mold and fungus growth Overwatering can cause root rot and yellowing of leaves
You can clean the leaves of dust Leaves get neglected and dust can build up if not cleaned manually
Requires misting bottleRequires a watering can

Should you add fertilizer while misting 

Soluble fertilizers can be added to misting mix when nutrients are required by the plant suffering from a certain type of deficiency. 

Potted plants will require Nutrients to be added on a scheduled basis as being confined to a plant pot will only provide a certain amount of nutrients for a finite period of time. 

When adding foliar fertilizer you should take into consideration the time of day. 

Foliar fertilizer should be applied during early mornings between 7am and 9am or late evenings after 5 pm. 

During these times the stomata located on the underside of the leaf open and readily absorb nutrients into the leaf. 

Therefore it is recommended when applying foliar fertilizer you should spray mainly on the underside of the leaves. 

Research conducted by the Atomic Energy Commission in the late 40’s and 50’s, showed that fertilizer applied to the foliage of the plant was absorbed 8 to 10 times faster than traditional methods. 

One factor that must be considered when using foliar fertilizer is that the spray bottle doesn’t get clogged. 

Small undissolved particles can easily get stuck in the holes of the nozzle, blocking the outward flow. 

There are misters that are made with this in mind and there is a removable strainer installed so that pluggage would not be a problem. 

Misters

Types of misters –

Squeeze nozzle Misters

These are containers that can be filled with tap or rainwater which are then applied to the plants as a mist by squeezing a trigger at the top of the container. 

Apart from purchasing a dedicated mist bottle, you can reuse any detergent spray bottle you may have laying around. 

Caution must be taken when using these bottles as they should be cleaned thoroughly before use. 

Additionally, the first few sprays should be done in a sink to properly clear the straw and nozzle of any chemical residue before using it on the plant. 

Pressurized Misters

These misters can be pressurized both electronically or manually. 

The manually pressurized bottle comes with a pump handle that is used to increase the pressure within the bottle. 

The bottle is made of thick food-grade material and a relief valve to remove additional pressure when it is not in use. 

When pressurized the nozzle can spray up to half the contents of the bottle before repressuring. 

With the electrically pressured bottle, it takes the manual work out of the equation which makes it even easier for you to mist your plants. 

As you spray, a small air pump increases the pressure within the bottle allowing you to use the entire contents of the container by just pressing a button. 

Another viable option when it comes to misting is a humidifier. 

Plant Humidifier

Humidifier (Misting Alternative)

This comes in handy if you don’t have a spray bottle or mister.

Misting and humidity goes hand in hand and having a humidifier for your plants can definitely be beneficial when it comes to providing care when you are not around. 

One way this can be done is by connecting the humidifier on a timer switch which can be turned on remotely via an app or based on a set schedule. 

In the event that you don’t have this misting equipment, you can adopt the practice of placing the plant in the bathroom as explained above.

The Geniani portable humidifier from amazon provides the ideal environmental humidity for healthy plant growth. You can find it by clicking here.

geniani portable humidifier

Summary

Although misting provides a good way of providing water for plants, it should be done on a routine basis to prevent any plant-related ailments associated with underwatering.

Misting provides a temporary hydration fix for plants since the water can also evaporate quickly from the leaves if there is low humidity.

Therefore misting in addition to soil watering should be done if you are leaving your plant for more than a day before misting again. 

The soil water will not evaporate as fast and will provide lasting moisture until you can water again.

JayLea

JayLea has a passion for plants and has been gardening since 2015. He has valuable knowledge about gardening and houseplant care and can answer everyday practical questions that every plant owner has.

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