Let’s Go Farming


Vertical/Sack Vegetable Gardens

Vertical/sack gardening offers an excellent solution for people living in the cities who don’t have much outdoor space. Last week, one of my organic gardening mentors introduced me to vertical vegetable gardening – and immediately I bought a potting mix and used the whole sack for vegetable sack gardening. I will also introduce same to my school gardening students.

This type of vegetable gardening enables the maximum use of ground space by using all sides and top of the bag for cultivation.

How to start a vertical/sack-garden:

To make your sack garden, you will require the following:

  1. One or more woven burlap sacks or plastic bags depending on how much space you have, but they must be 50-90kg sacks
  2. Enough soil – preferably potting mix, or dirt mixed with compost or animal manure – to fill the bag. You can also add fertiliser or liquid feed to the soil.
  3. Enough small stones or pebbles to use for the watering system.
  4. Seedlings for the crops to be planted. Crops that have been found to do well in sacks include tomatoes, onions, spinach, kale, lettuce, amaranth or African nightshade. Select seedlings according to their productivity, resistance, maturation length, compatibility with local conditions, etc. Consider planting leafy vegetables that keep on growing even after the leaves have been harvested like kale, spinach, leafy onions, etc. A device capable of cutting through the bag is also required.
  5. Water is a necessity because the bag garden needs to be watered every day.
  6. Sacks with central stone wells are better than sacks with horizontal layers of stones and soil, because the first ones allow growing plants on the sides of sacks, too, consequently increasing the sack’s productivity.
  7. Ensure that you position the sack in its final position while planting, as moving a sack full of wet soil, pebbles and plants is cumbersome. Preferably, it should be positioned in a spot where it will receive as much sunlight as possible.

How to prepare a sack garden

  • Step 1: Assemble all the materials needed for this project. You will need a big sack (50-90kg), stones/pebbles for drainage, planting soil & manure (or just use potting mix) and seedlings.
  • Step 2: Create the watering system. You can use a hollow tin or a long and wide pipe to create the drainage system. Fill the hollow tin with ballast and the space between the tin and the Sack with the soil and manure mixture. Remove the tin and place it on the new level and repeat the process until you get to the top of the sack.
  • Step 3: The next step is planting. Make small holes on the bag wall using a sharp stick or knife. Leave about 15 cm between each hole. Ensure the holes are not in the same vertical line to prevent blocking each other from getting direct sunlight. Carefully plant the seedlings in the holes so as not to damage the roots. Press the soil around the seedlings using your fingers to make it firm.
  • Step 4: Water your plants through the watering column that you created for the plants to thrive. Water more frequently in very hot weather, making sure not to get the leaves wet.
  • Step 5: Feed with liquid fertiliser or liquid seaweed once a week when plants are ‘fruiting’.
  • Step 6: Sack gardens can be recycled for the next growing season. When the plants die, the dead plants and roots should be taken out of the dirt. When the growing season is over, the sacks used should be emptied – with the stones and any dead roots taken out of the dirt.

Advantages of Sack Gardening

  • Sack gardens do not need agricultural land or much water, as they can do well even in areas where there is a high population density that prevents traditional gardening.
  • Gardening in sacks gives you the advantage of mobility, making it a more stable investment as you can move and put it wherever you want.
  • They are easy to prepare, as they do not require any specific technical knowledge or expertise. Sack gardens use simple and inexpensive materials such as sacks, stones, soil and manure
  • Where there is little ground-level sunlight to grow vegetables, Sack gardening helps as the plants are planted vertically, so they can get enough sunlight.
  • It helps in areas where the soil is contaminated.
  • Where there is a high chance of natural disasters, such as floods or mudslides, sack gardening is ideal.
  • Sack gardening is also beneficial in drought-prone areas or where water very limited.
  • It allows for diversifying diets, and as a result addresses micronutrient deficiencies

Disadvantages of Sack Gardening

  • One of the biggest challenges in sack gardening is plant pests and diseases, as crops in a sack are planted close together – hence it’s very easy to spread pests and disease to other plants in the sack if pest and disease control is not done properly.
  • Apart from the flat top of the sack, plants cannot grow from seeds in a sack garden. This is because of the limited nature of the garden, whereby the sack contains the soil, and plants growing in the soil only penetrate through specific predetermined holes. Some plants growing from a seed may not grow through one of these holes and instead be stuck inside the bag – where without sunlight it cannot grow. The best way to ensure that plants will grow is to transplant seedlings into said holes, so that they’ve already escaped the sacks and are exposed to the outside environment.
  • Eventually, the sack will require disposal if it is made of oil-based plastic. This is after usage or when damaged.

I hope this is a good share and I will have some gardeners try it out with me. Do share how it’s going with your vegetable gardens at home, school or the office with me via [email protected] or on our social media platforms @letsgofarmingtv

Planting your garden in a sack should produce enough vegetables to ensure you and your family have plenty of healthy greens. If you are planning to have more than one sack in your backyard/balcony, the space between every bag should be one metre.

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