How To Build A Brassica Cage – Garden Tips 2024

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One of the worst parts of gardening is seeing insects and pests devour your crops. One way to prevent this from happening is to use a brassica cage.

How to build a brassica cage? Start by thinking of the size of the brassica cage you want and then collect the materials you will need, such as wood for a frame, ribbing for the structure, and netting for the top of the cage. You can create a custom brassica cage to fit over any size of the garden.

What is a brassica cage?

First, what exactly is a brassica? Brassica is a genus of plants that mainly includes cabbages, cauliflower, broccoli, bok choy, and rutabaga.

Even though many vegetables fall under the category of brassica, they all attract the same type of pests which can wreak havoc on your garden. In order to protect vegetables in the brassica family, as well as other susceptible crops, you can create a cage.

A brassica cage is a small enclosure that stops pests as small as cabbage white butterflies and as large as pigeons. The cage needs to be open, however, to allow sunlight and water to reach the plants.

How does a brassica cage work?

A brassica cage works by keeping out pests. While there are different materials you can use to construct a cage, they will all have holes that are small enough to keep out pests (both birds and butterflies) but not be an enclosed structure like a greenhouse.

The structure can be permanent or temporary, depending on how often you plan on planting brassicas. If you want brassicas to be a constant in your garden, you can create a large cage with a door but if you want a more temporary structure, you can create a cage that can be moved on top of your growing area.

How to build a Brassica cage

There are many types of brassica cages but we’re going to outline a temporary structure. This is a cage that can fit over the top of your growing area and then be removed when it is time to harvest.

Gather materials

You will need to start with long pieces of treated wood that are measured to frame your growing areas. You will then need pieces of bendable pipe that will create the ribbing of the cage.

Other materials include scaffolding netting, cable ties, wood screws, angle brackets, and wood staples.

Measure your area

Start by mapping out the area you want to build in. Remember that brassica cages can be used for other crops, so it may be easier to enclose an entire garden bed.

Once you have your measurements, you can cut your wooden pieces to length so you create a wooden frame around the garden. Use the metal brackets and screws to secure the frame together.

Add the piping

An easy way to create a brassica cage is by bending tubes into arches and attaching them to your wooden base. You will need a drill bit the same diameter as your tubing.

Drill holes about two feet apart along each side of the wooden frame and insert your tubing. To make this part more secure, you can use wood glue.

Cover with netting

Now that you have the outline of your structure, you can add the netting. Cut it to size and use a stapler to attach it to the wooden frame.

Depending on the size of the netting, you may need to use multiple pieces along the structure. Just make sure the netting is tight and overlaps these pieces so there are no gaps.

You can use the ties to secure the netting better into place around the tubing.

How big is a brassica cage?

As there are many variations of brassica cages, there is no set size for one. Indeed, the benefit of making your own brassica cage means you can decide on the dimensions.

For permanent brassica cages that have posts set into the ground, it’s better to have a larger cage that encompasses your entire garden. However, portable cages should be small enough that you can easily lift them up when you need access to your garden.

Most brassica cages end up being about 2 feet by 4 feet. This size is large enough to cover a garden bed and won’t be too bulky so that you can lift it up by yourself and not worry about wrecking your garden.

Height-wise, you want your brassica cage to be at least 4 feet tall. Many crops in this family, including cabbages, can grow to be quite tall, so you don’t want to limit their growth.

How do I protect my brassicas?

Vegetables in the brassica family, including cabbage, broccoli, cauliflower, and turnips, are attractive to a lot of pests. This is why they need to be protected.

Aphids are especially attracted to crops in the Brassica family, as are white butterflies. As for larger pests, pigeons will fly over and eat the crop, as wild deer.

Pollination is not needed for brassicas to develop as you will harvest the vegetables before they flower. As a result, you can cover your crop with a tight netting that keeps all insects out, including beneficial ones.

Netting is perhaps the best way to protect your brassicas. Ensure there are no gaps in the netting and that it reaches all the way to the ground so crawling insects can’t get in.

Cover your crops soon after you plant to avoid insects laying their eggs. As long as sunlight and water can penetrate through your cage, you can keep it in place until it is time to harvest.

Can I purchase a brassica cage?

If you aren’t sure about your DIY skills or simply don’t have the time, you can purchase a pre-built brassica cage. These can be bulky, however, so another option is a kit that includes all your materials.

There are many similar structures that work just like a brassica cage but go by different names, such as fruit cages. These can all be used, as long as the netting area is tall enough and the net holes aren’t too large.


Don’t let all your hard gardening work be destroyed by pests. Use a brassica cage to protect your cabbage, cauliflower, and broccoli from common pests.

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