Why Are Hay Bales Wrapped In Different Colours?

Bales wrapped in plastic are commonly referred to as Silage Bales. These Silage bales are often wrapped in colourful plastic. We are often asked if these different colours of wrap mean anything?

Hay Bales or Silage Bales wrapped in different colours has no real meaning. The different colours are just what the bailing contractor has on hand at the time. There are times when bales might be wrapped in a colour to represent a special time of the year or bring awareness to a special cause.

If you’re eager to learn why some hay bales are wrapped in pink plastic versus yellow or purple, you’ve come to the right place. By the time you’re done reading, you’ll know what each hay bale colour represents so you can wrap your own hay in the appropriate hue!


Hay bales wrapped in green
Green is the standard colour for wrapping


Why Are Hay Bales Wrapped in Pink?

You’re trying to determine which color plastic would be best to wrap your freshly baled hay. You’ve heard of other farmers using pink plastic, but you’re not sure why.

You’re only likely to see pink hay bales throughout October for Breast Cancer Awareness Month.

Pink has been associated with Breast Cancer Awareness Month for a long time.

Most of the time, you’ll see people wearing pink ribbons for Breast Cancer Awareness Month, which is to support the doctors and medical teams working for a cure for breast cancer.

The ribbons are also to honor those who have unfortunately succumbed to the disease as well as current breast cancer fighters and survivors.

Sure, a farmer could wear a pink ribbon, but not when they’re working. By baling hay in pink plastic, it’s a much more overt symbol of support than a ribbon. The bright pink hue of the hay bales is impossible to miss, especially if it’s a larger bale.

Obtaining pink plastic for hay bales usually doesn’t cost more money than buying the plastic in other hues, so there’s no reason not to decorate your hay bales pink for the month of October!


Why Are Some Cotton Bales Wrapped in Different Colours?

Pink is not the only colour you will see other farmers use when wrapping cotton bales in plastic. Yellow, purple, and green are other popular hues as well. Do these colours have their own respective meanings?

For the most part, they do, so let’s go over those meanings now.



In Australia, New Zealand, Portugal, the United Kingdom, and Ireland, purple hay bales are popping up on farms more and more often.

Like pink hay bales are for Breast Cancer Awareness Month, purple bales could be in honour of the Children’s Medical & Research Foundation.

If you enwrap your cotton bales in purple, then you’re doing a great thing for kids!  



We’ll talk momentarily about what black and white plastic for cotton bales means, but as an alternative to black, some farmers will use green plastic instead.

Like yellow wrap, green plastic doesn’t have any particular meaning. Rather, green plastic is the standard for wrapping bales of hay, more commonly referred to as Silage. 


Why Are Hay Bales Wrapped in Black?

Dark color absorbs sunlight. If you’ve ever worn dark-colored clothing on a hot summer’s day, you know this all too well. That’s why you’re typically advised to wear lighter hues in the heat, as black will only make you hotter.

When black plastic-wrapped hay bales sit out in the sun, the temperature of the bale will rise quickly. This makes the plastic film’s permeability go up. In other words, the black film becomes even more porous than it was originally.


Hay bales wrapped in black
Silage bales wrapped in black plastic

Now oxygen can pass through the plastic at a much higher rate than usual, at least six times the average rate when the temperature is 50 degrees Celsius (122 degrees Fahrenheit).

When the temperature is only 15 degrees Celsius (59 degrees Fahrenheit), the rate of oxygen permeating the black plastic is much less.

What impact do the elevated temperatures and increased oxygen have on the hay bales? Butyric acid levels increase, which means the hay has more bacteria.

The bacteria can cause the hay to take a serious hit in quality. In some instances, you might not even be able to sell the hay because the feed losses were that significant.

Keep in mind that this effect extends not only to black plastic, but cotton bales wrapped in other dark hues such as navy blue or even purple.

If you must use these colors for baled hay, then you should do your best to keep the hay out of the sun.

Storing the hay in a temperature-controlled environment (provided your company can afford such a thing) will also prevent the temperature increases that make the plastic more permeable.


Studies On Black Wrap Film

Back in 2002, a study conducted at the Reading University UK / CEDAR (Centre of Dairy Research) drew a comparison with the effects of differing silage wrap colours.

Bales wrapped in black with less layers had significantly more nutrient and fodder loss than bales wrapped in Green.


Why Are Hay Bales Wrapped in White Plastic?

White plastic-wrapped hay bales are a very common sight on farms. Unlike black, which absorbs heat, white reflects it.

If a bale of hay wrapped in white plastic was sitting in the same conditions as a bale of hay wrapped in black plastic, the black plastic would absorb heat while the white plastic doesn’t.

The white plastic-wrapped hay bale would maintain its temperature for a lot longer. As a result, the film doesn’t become more permeable, which means oxygen can’t enter at nearly as high of a rate as it does for hay that’s wrapped in black plastic.


Should You Wrap Your Hay Bales in Different Colours?

You may be debating if the additional expense of wrapping your hay bales in plastic is worthwhile to your company’s bottom line. We say yes, as using plastic has many benefits. Let’s talk about them now.


Less Risk of Weather Damage

Since plastic wrap encompasses nearly the entire hay bale when you cover the stuff in film, the hay almost becomes weatherproof. It’s still a good idea to safeguard your hay in a barn, shed, or another overhead structure.

However, if the hay were to get wet, the plastic film would take the brunt of the damage, so to speak, not the hay.

This is critical, as hay is not supposed to get too wet.

When the moisture levels increase, so too do bacteria as well as fungi. The presence of bacteria and fungi can cause the internal temperature of the hay to increase, putting the hay at risk of spontaneous combustion.

This can lead to significant financial losses for your operation!


Increased Leaf Retention

Potentially because enwrapping hay bales maintains more of the original structure, using plastic wrap can retain the leaves in your bale. The greater the number of leaves, the more nutrients the hay contains and the more easily digestible it is.

You can charge more money for this higher-quality hay.



Silage bales are generally wrapped in various colours due to what is on hand at the time although Green coloured wrap is the most common one used throughout Australia.