Gardening on balconies and terraces has been very trendy for several years. More and more people don't want to go up despite the lack of spacehome-grown vegetables and fruitdo without and look for easy-to-implement ideas for space-saving and easy-care raised beds. Today we will show you a creative and practical DIY raised bed for balconies and terraces that allows fans of urban gardening to grow many useful plants in the smallest of spaces.
How does this DIY raised bed work?
While the idea of a vertical garden isn't new, this raised bed takes the concept to a whole new level and perfects it. The secret behind it is called: compost worms! A pipe is mounted in the middle of the barrel, which serves as a composter for food waste. The worms convert food scraps into an excellent fertilizer (humus), which is the best organic fertilizer plants can receive. The pipe has enough holes all around so that the worms can crawl into the soil and thus also fertilize the plants. They allow the soil to remain fertile for a long time and prevent the need for frequent soil replacement.
In addition, during irrigation, water enters the pipe and washes out the waste products. The water flows into a vessel under the barrel and is reused for watering, returning nutrients to the soil. This means we eliminate fertilizers, save water and waste less food.
Are the compost worms really necessary?
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.
The compost worms (Eisenia foetida) belong to the earthworm family. Because of their color, they are often referred to as “red Californian earth worms”. They hate strong light and drought and cannot survive outside the barrel. Once they are filled into the pipe, they are barely visible, but their benefits are immense. The humus they produce is a wonderful substance for the soil, containing virtually everything the plant needs, including nitrogen, phosphorus and potassium (NPK).
If, despite all the advantages mentioned above, you have decided not to add the worms to the barrel, we recommend fertilizing the raised bed artificially with a little liquid fertilizer (especially if you want to grow edible vegetables). Of course, you can also just plant flowers in the bags.
How can you build this raised bed for your balcony yourself?
To build this raised bed yourself, you need a wide-mouth barrel, preferably made of food-safe polyethylene, or PE for short. Recycled barrels can also be used, for example those from the food industry that are used to transport glucose syrup. For a large vegetable garden, a barrel with a capacity of 220 liters is ideal. For a mini raised bed for the balcony you can use a 60 liter barrel.
First, the slots are drawn all around the barrel. The distance between the individual levels should be around 15 centimeters. For example, 5 – 6 levels with 8 to 10 slots each are optimal.
Holes are then drilled through the start and end points and then the slots are cut with a jigsaw. So that these can be expanded and shaped, the plastic is heated with heat. For this step it is better to work with two people. While one person holds the hot air dryer, the other can insert the wooden wedges (or another suitable object). These must remain in the hole until the plastic has cooled down.
After all the pockets have been formed, you can continue with the inner tube for the kitchen waste. For a 200 liter barrel you need a pipe with a diameter of around 190 mm and a length of around 1.5 meters. The pipe must 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 all around this pipe.
A hole is cut out in the middle of the bottom of the barrel, with the same diameter as the inner tube. To prevent the pipe 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 tube is closed with a cap. To drain the barrel, a few drainage holes are drilled all around it in the lowest places.
Does the barrel always have to be on stilts?
If the barrel is placed on the ground without feet, it may be unstable due to the pipe cap. It is therefore recommended to place the raised bed on stilts or another frame with legs.
The feet serve several purposes:
1. They make access to the barrel and plants easier.
2. They make cleaning under the barrel easier.
3. They allow the collection of runoff water, which is essentially liquid humus. This worm leach is one of the best liquid fertilizers.
4. The barrel can be moved and rotated more easily if necessary.
5. This will allow you to open the cap at the bottom of the barrel so you can remove the compost.
Where should you put the raised bed?
The right location is very important and you should consider a few factors before filling your raised bed:
Location and sunlight
A spot that can provide the plants with at least 3 hours of sun per day is ideal. This is the most important prerequisite for photosynthesis in plants. Tomatoes, peppers, zucchini and cucumbers, for example, need a lot more sun.
If your balcony is completely in the shade, fortunately there are some herbs and vegetables that can also grow there. Good crops that thrive in the shade on the north side are spinach, cress, chives and some types of lettuce.
How is the raised bed watered?
The raised bed can generally be watered with an irrigation hose or a watering can. If you are often away from home or forget to water, you can use an automatic irrigation 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 allows you to maintain your raised bed more easily.
Fill the balcony raised bed correctly
As soon as the loft bed has found its place in a well-chosen location, it can be filled.
Which 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 1:1 ratio. It is important to fill the barrel to the top with soil because the substrate will lose some of its volume when it is first watered.
Isn't the raised bed too heavy for the 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 around 100 kg and a mini raised bed weighs around 35 kg, so weight is not a problem.
The PE barrels are 100 cm high and 60 cm wide. When placed on a frame, the height is approx. 135 cm. The smaller barrel is 45cm wide and 75cm high when placed on its feet.
Initial watering
Once the barrel is filled with soil, place a container under the barrel where the irrigation debris can collect. Start watering the raised bed. When water begins to drip into the bottom of the container, you know the substrate is saturated and ready for planting.
Plant the raised bed
Now you can insert the plants into the slots. To have a better chance of success, plant young seedlings rather than seeds. Think in advance about which plants you want to put in your raised bed. The cultivation of variousVegetables and herbs from different types togetherin a raised bed has several advantages. Also take into account the requirements of the plants and their properties. Varieties that grow very large, such as kale, cherry tomatoes, peppers and eggplant, should be planted higher up. Planting the raised bed is very easy and fun. You can find more inspiration in our article:Gardening on the balcony: 10 ideas for what to plant in the raised bed
Fill the compost worms into the inner tube
Place a handful of soil into the worm tube and empty the bag of red worms into it. This is followed by a cup of leftover food and then another handful of soil.
What should you feed the worms with?
It is advisable to feed the worms soft food and preferably of high nutritional value. They prefer 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 onwards, continue with 3 cups of food per week.
The worms reach a length of approx. 5 cm. Each worm eats approximately 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: there will be no population explosion because they adapt their numbers to existing conditions: available space, amount of food, etc.
How often to water raised beds?
After planting, when the seedlings are still young, it is recommended to water each individual pocket. After about two weeks, when the roots have established themselves, the raised bed only needs to be watered from above. 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. As a result, the decomposition products of the worms (humus in a liquid state) are returned to the barrel for the benefit of the plants.
