Whether you own a glass or plastic greenhouse it can easily overheat when the weather is too hot. To protect your plants from overheating you need to provide good ventilation and shading.
There are many ways of shading a greenhouse, but today I want to talk about the greenhouse shade cloth. Let’s start with the quick introduction to what shading is.
What is a Greenhouse Shading?
Shading is a way of keeping the greenhouse cool during the hotter months. It reduces the temperature inside by minimizing the amount of light passing to the greenhouse.
You might think that good ventilation is enough to keep the temperature to the optimal value, but you are forgetting about the radiant energy from the sun.
It easily builds up inside the greenhouse and increases the temperature which is dangerous for many plants. Of course, the growth of plants directly depends on the amount of sunlight, so keep shading to the minimum.
How the shade cloth cools the greenhouse?
As I have already mentioned the radiant energy from the sun heats the greenhouse. Particularly the infrared radiation. It is not visible to the human eye as it has longer wavelengths as those of the visible light.
For the active photosynthesis plants need blue to red range lights of the total light spectrum which are within 400-700 nm range. Anything higher than this range is damaging for the plants.
Exposure to the excessive amounts of the infrared light, particularly in the far end of the spectrum can damage the plants. It can be anything from discoloration to the to early growth spurts which impact on health, or can even lead to the death of plants.
Greenhouse shade cloth reflects the sun rays back or partially blocks them. Plants only need 1.5-2% of the transmitted sunlight for the photosynthesis.
Does shade cloth reduce heat?
Shade clothes typically reduce the light level by 75% and turn it into the heat. The temperature of the cloth raises as it acts as a solar collector.
The temp of the cloth is higher than temp of the air, so the heat energy goes up. As it goes up, the cool air draws from below in the process known as evaporative cooling.
What is a Greenhouse Shade Cloth made of?
The most common materials for the cloth are polyethylene and polypropylene. You can find a variety of shade cloths of different densities and degrees of shade ranging from 5 to 95 per cent.
Is shade cloth waterproof?
A good shade cloth should be water resistant to work well when it is raining or you are using an irrigation system to water your plants.
A waterproof shade cloth is made of the 90 per cent shade fabric treated with UV stabilized resin to make it water resistant.
Types of Shade Clothe For Greenhouse
Today, you are most likely to find two types of shade clothes on the market: knitted and woven.
Knitted is constructed from the polyethylene and it looks like one continuous yarn is looped to form something similar to the tiny rows of braids.
Woven is made from woven polypropylene and represents multiple yarns crossing each other at right angles to create the grain, like a basket. The lifespan of the woven shade cloth is from 10 to 12 years while the knitted one lasts 7-10 years.
Knitted vs woven shade cloth
The woven shade cloth is typically 30% heavier than knitted one, hence tends to be more expensive. Also, the lightweight knitted option is easier to install. Both types are UV resistant and can withstand the extreme sun exposures.
The woven shade cloth is only available in black color. Knitted ones come in the variety of colors. The main difference between the both options is that woven will unravel if cut.
This is due to the structure of the cloth. If a hole forms in the knitted shade cloth the threads running in different directions will not unravel.
Moreover, knitted option is resistant to the most of the horticultural chemicals and detergents. The knitted fabric can be stretched up to 3 per cent whilst woven can’t.
Overall, woven shade cloth has multiple applications in wind screens, pet kennels and patio shading whilst knitted shade cloth is widely used for a greenhouse shading.
What percentage shade cloth to use?
Both knitted and woven shade clothes come in different densities. The density of the shade cloth is referred to as percentage.
The percentage of the shade cloth corresponds to the amount of light which is blocked by this cloth. The shade clothes typically come in 30%, 55%, 63%, 75%, 80% and 90% options.
You need to choose a shade cloth according to the plants you are growing in your greenhouse. It is crucial to choose a cloth of the right density to allow a sufficient amount of sunlight for a healthy growth.
The reference range for most vegetables is 30-50% shade cloth. Also, for the most plants shade cloth within 30-60% is ideal.
However, there are some plants which require specific shading conditions. For example, orchids and ferns which are shade loving plants require 75% shade cloth to receive the appropriate levels of sunlight.
What is the best shade cloth for greenhouse?
The best shade cloth for greenhouse is a water resistant knitted. It will not unravel if cut ans is available in a variety of colors and percentages.
A shade cloth of 30-50% is ideal for most vegetables, however, some plants require a shade cloth of 30-60%.
How to put shade cloth on greenhouse?
Before buying a greenhouse shade cloth go ahead and measure the width and lengths of the roof using a tape measure. Ideally, the shade cloth should drape down the sides of the greenhouse from the roof.
To make sure these will be equal measure the distance from the top of the roof to up to two thirds down of the both sides.
Take into account that cloth connects to the frame of the greenhouse and is not overhanging on the sides.
Remember, you don’t need to cover the sides of the greenhouse completely (that is why you are measuring two thirds on the sides). Sunlight should still enter the greenhouse.
There is a chance that you might need to cut the cloth after you bought it during the installation. To avoid that I found an option where you can get a shade cloth customized to your desired size!
However, bear in mind that you will need to order it in advance as it takes up to one month to make and deliver the cloth.
So, if you are after an easy installation I am going to share the easiest way with you!
Step-by-step shade cloth installation guide
After you took the measurements and ordered your cloth it’s time to get ready for the installation.
Some accessories might come together with the cloth, some tools you should have at home and maybe you will need to get a couple of things.
Here is how to do it:
- Attach S-hooks to the base of the greenhouse.
- Place the hooks 2 feet apart to match the shade cloth grommets.
- Place the shade cloth over the roof of the greenhouse.
- Use bungee cords to attach the grommets to the hooks in the base.
- To secure the cloth on the frame you can use snap on claps for the PVC pipe greenhouse. If your greenhouse is made of wood or aluminum I would recommend using lock channels.
How to clean my greenhouse shade cloth?
To understand what is the best cleaning method for a shade cloth we need to learn a little bit about its composition.
As I have already mentioned the shade cloths are made of the high density polyethylene. Therefore, it is resistant to dirt, moisture and some chemicals.
This means that dirt doesn’t adhere to the single yarns of the cloth. Also, the material is durable because it doesn’t rot.
However, when exposed to the excessive amounts of dust and moisture the fabric can look grey.
That is why people think that it is molded which is not true. Actually, dirt and moisture get stuck in the knit pattern and give the fabric grey appearance.
So, the easiest way to avoid it is to clean your shade cloth regularly to prevent the build-up of moisture and dirt.
How do you wash a shade cloth?
DO NOT wash the shade in the washing machine, clothes drier or use a stiff brush, scouring pad or an abrasive cleaner!
To wash the cloth use a weak concentration of non-abrasive pH neutral detergent with warm water.
Make sure that the detergent you use doesn’t have any acidic chemicals or solvents which weaken the cloth’s resistance to UV radiation.
It is very important to let the fabric dry thoroughly after the clean, so do the cleaning on a sunny day.
Greenhouse shade cloth cleaning steps:
- Remove the shade cloth from the greenhouse and lay it flat on a smooth, clean surface;
- Apply cleaning solution described above to the fabric with a long soft bristled mop or brush;
- Work along the fabric in sections to cover the shade cloth fully;
- Rinse it well with a strong flow of fresh water from your backyard hose;
- Let your cloth to dry;
- Re-install your shade cloth on the greenhouse.
There are more shading options which you can use for your greenhouse. Please let me know if you want to know more about them. I hoped you found this information useful.
Happy growing everyone!