Skip to content

Grow up to 60 crops on your balcony with this DIY raised bed!

Gardening on balconies and terraces has been the latest trend for several years. More and more people do not want to do without home-grown vegetables and fruit despite the lack of space and are looking for easy-to-implement ideas for space-saving and low-maintenance raised beds. Today we will show you a creative and practical DIY raised bed for balcony and terrace, which allows fans of urban gardening to grow many useful plants in a very small area.

How does this DIY raised bed work?

Raised bed and compost in one with compost worms

The idea of a vertical garden is not new, but this raised bed takes the concept to a whole new level and perfects it. The secret behind it is called: compost worms! A tube is mounted in the center of the barrel that serves as a composter for food waste. The worms turn food scraps into an excellent fertilizer (humus), which is the best organic fertilizer plants can get. The tube has enough holes all around to allow the worms to crawl into the soil and thus fertilize the plants. They allow the soil to remain fertile for a long time and prevent the need for frequent soil replacement.

raised bed for balcony and terrace for herbs and lettuce

Also, during irrigation, water enters the pipe and washes out the waste products. The water flows into a container under the barrel and is reused for watering, returning nutrients to the soil. Thus, we eliminate fertilizers, save water and waste less food.

Are the compost worms really necessary?

space saving raised bed for balcony and terrace

Yes, the worms are the internal engine of the raised bed that makes the plants grow insanely. And anyone who is afraid of them should know that they never come out of the barrel and have no contact with the edible parts of the plants.

Compost worms (Eisenia foetida) belong to the earthworm family. They are often called red californian earth worms because of their color. They hate strong light and drought and cannot survive outside the barrel. After they are stuffed into the barrel, they are barely visible, but their benefits are immense. The humus they produce is a wonderful substance for the soil, and contains virtually everything the plant needs, including nitrogen, phosphorus and potassium (NPK).

Mini raised bed for herbs and flowers for terrace

If, despite all the above advantages, you decided not to put the worms in the barrel, we recommend artificially fertilize the raised bed with a little liquid fertilizer (especially if you want to grow edible vegetables). Of course, you can just plant flowers in the pockets.

How to build this raised bed for balcony yourself?

DIY raised garden bed from PE barrel

To build this raised bed yourself, you will need a wide-necked barrel, preferably made of food-grade polyethylene, or PE for short. Recycled barrels can also be used, for example, those from the food industry, which are used to transport glucose syrup. For a large vegetable garden, a barrel with a capacity of 220 liters is most suitable. For a mini raised bed for balcony, you can use a 60-liter barrel.

How to build a raised bed from a plastic barrel

First, draw the slots all around the barrel. The distance between the levels should be about 15 centimeters. For example, 5 – 6 levels with 8 to 10 slots each are optimal.

Then holes are drilled through the starting and ending points, and then the slots are cut with a jigsaw. In order for them to be expanded and shaped, the plastic is heated with heat. For this step, it is better to work in pairs. While one holds the hot air gun, the other can insert the wooden wedges (or other suitable object). These must remain in the hole until the plastic has cooled.

Make bags for planting

After all the pockets are formed, you can move on to the inner tube for the kitchen scraps. For a 200-liter drum, you will need a pipe with a diameter of about 190 mm and a length of about 1.5 meters. The pipe should not be too small, so that there is enough space for the compost. Holes with a diameter of at least 20 mm are then drilled into this pipe all around.

Raised bed for balcony with herbs and flowers

At the bottom of the barrel in the middle, another hole is cut out, with the same diameter as the inner pipe. To prevent the tube from slipping through the hole in the bottom of the barrel, it is sealed around it with silicone or hot glue. Last but not least, the open pipe is closed with a cap. To drain the barrel, drill a few drainage holes around it at the deepest points.

Does the barrel always have to stand on stilts?

Raised bed for strawberries from plastic barrel

If the barrel is placed on the ground without feet, it may be unstable because of the pipe cap. Therefore, it is recommended to place the raised bed on stilts or another frame with legs.

The legs serve several purposes:
1. they facilitate access to the barrel and plants.
2. they facilitate cleaning under the barrel.
3. they allow the collection of the water that runs off, which is basically liquid humus. This worm leaching is one of the best liquid fertilizers.
4.The barrel can be moved and rotated more easily when needed.
5.This allows you to open the cap at the bottom of the barrel so you can remove the compost.

Where should you put the raised bed?

Grow lettuce in a DIY raised bed on balcony

The right location is very important and you should consider a few factors before filling your raised bed:

Location and sunlight
The ideal place is one that can offer the plants at least 3 hours of sun a day. This is the most important condition for photosynthesis of plants. Tomatoes, peppers, zucchini and cucumbers, for example, need much more sun.

Raised bed for strawberries without soil contact

Fortunately, if your balcony is entirely in the shade, there are some herbs and vegetables that can thrive there as well. Good crops that are comfortable in the shade on the north side are spinach, cress, chives and some varieties of lettuce.

How to build a raised bed without contact with the ground

How is the raised bed watered?

Basically, the raised bed can be watered with an irrigation hose or watering can. If you are often away from home or forget to water, you can use an automatic watering system. The hoses curl inside the barrel and water the plants with a precise drip directly to the roots.

Whether you use an irrigation system or not, being close to a water source will allow you to more easily maintain your raised bed.

Fill the balcony raised bed properly.

Mini raised bed for balcony with herbs and flowers

Once the raised bed has found its place in a well-chosen location, it is ready to be filled.

What soil for the raised bed?

The soil in the raised bed should be light, well-drained, nutritious and water-retaining. It is recommended to mix garden soil and compost soil in a ratio of 1:1. It is important to fill the barrel with soil to the top, because the substrate loses some of its volume when it is first watered.

Isn’t the raised bed too heavy for the balcony?

Raised bed with lettuce and herbs on balcony

For a standard balcony, the maximum load is 250 kg per square meter. When filled, a raised bed in a 200-liter barrel weighs about 100 kg and a mini raised bed weighs about 35 kg, so the weight is not a problem.

The PE barrels are 100 cm high and 60 cm wide. When placed on a rack, the height is about 135 cm. The smaller barrel is 45 cm wide and 75 cm high when placed on its feet.

Initial watering

Raised bed in barrel watering

Once the barrel is filled with soil, place a container under the barrel where irrigation residue can collect. Begin watering the raised bed. When the water begins to drip into the bottom of the container, you know the substrate is saturated and ready for planting.

Plant the raised bed

Planting raised bed with flowers and herbs

Now you can insert the plants into the slots. To have a better chance of success, plant young seedlings rather than seeds. Consider in advance which plants you want to put in your raised bed. Growing different vegetables and herbs from different species together in a raised bed has several advantages. Also consider the plants’ requirements and their characteristics. Varieties that grow very large, such as kale, cherry tomatoes, peppers and eggplants, should be planted more on top. Planting the raised bed is very easy and fun. For more inspiration, check out our article: Gardening on the balcony: 10 ideas of what to plant in the raised bed.

Fill the compost worms into the inner tube.

With what to feed compost worms in raised bed

Add a handful of soil to the worm tube and empty the bag of red worms inside. This is followed by a cup of food scraps and then another handful of soil.

What should you feed the worms with?

Compost worms like banana peels

It is recommended to feed the worms with soft food and preferably of high nutritional value. They like best foods with a high sugar content, such as sweet and soft fruits, banana peels, mango, pumpkin, apples, peaches, etc. (can be given whole and with seeds). You can also feed coffee grounds to compost worms. They also digest bread, rice, pasta and other vegetables. It is advisable to avoid foods that are too spicy or fatty, as well as meat, dairy products, eggs, and acidic foods such as tomatoes and citrus fruits.

The compost worms should be fed gradually:

In the first month – one cup of food per week.
In the second month – two cups of food per week
In the third month – three cups of food per week
From the third month, continue with 3 cups of food per week.

The worms reach a length of about 5 cm. Each worm eats about half of its body weight per day and digests one kilogram of waste per year! They reproduce every 40 days under ideal conditions, but don’t worry: a population explosion will not occur because they adapt their numbers to existing conditions: available space, amount of food, etc.

Raised bed how often to water?

Raised bed with worm compost functionality

After planting, when the seedlings are still young, it is recommended to water each bag. After about two weeks, when the roots are established, the raised bed only needs watering from the top. Check the soil moisture with your finger and water when the soil is dry.

For watering, use the excess water that accumulates in the container under the barrel. It is still called worm tea. This will return the decomposition products of worms (humus in liquid state) to the barrel for the benefit of plants.

vertical raised bed with flowers for balcony and terrace