How to Make a Greenhouse from an Aquarium

Do you want an ideal house garden? Turning an old aquarium into a garden is a resourceful way to repurpose it. An aquarium has the best humid environment suitable for planting herbs such as oregano and basil. Making a greenhouse from an aquarium involves a step-by-step cleaning to the planting process.

To make a greenhouse from an aquarium, clean and sterilize the aquarium then pour and level 2-3 inches of coarse soil in it. Moisten the soil then spread the plants and seedlings on the level ground before covering them with a thin layer of soil.

Cover the top of the aquarium with a glass or plastic wrap and poke holes at the corners for oxygen circulation. 

With an aquarium greenhouse, you can plant at any season of the year, and you don’t have to wait for spring to start preparation. Your job is to water the plants and provide adequate lighting for proper photosynthesis.

Can you use an old aquarium as a greenhouse?

You can use an old aquarium as a greenhouse. The greenhouse gives plants a humid and controllable environment. You can easily monitor the growth of the plants from the top and sides of the aquarium. Also, an aquarium greenhouse provides room for lighting and makes it easy to control pests and diseases.

How to Make a Greenhouse from an Aquarium

The aquarium is suitable for starting seedlings that can be transferred to a garden once mature. Its also best for planting propagated cuttings where you can cut leaves or stems from a plant and encourage them to grow their roots. Other plants to grow in an aquarium greenhouse include decorative flowers.

A tank that holds 30 gallons of water and above makes a good greenhouse garden. They are big enough to have more plants and provide a sizeable garden. Do not use too deep or too shallow tanks for a terrarium. Reaching the plants could be challenging. Light may also not reach all areas of a very deep greenhouse aquarium.

How to make a greenhouse out of an aquarium

Here is a step by step guide on how you can make a greenhouse out of an aquarium

1. Cleaning the aquarium

If your aquarium still holds fish water, empty it first. Using warm, soapy water and a clean cloth, wash the aquarium thoroughly to remove dirt. Pay attention to cleaning the bottom and all corners of the aquarium to remove bacteria and other dirty deposits. 

Use clean water to rinse inside and outside the aquarium thoroughly. Check whether there are cracks on the tank to be repaired before you can start planting on it.

READ ALSO: How to Clean and Disinfect New Aquarium Plants

2. Sterilize the aquarium

You can get a sterilizer from your local warehouse. But the easy and affordable way is to use hot water. To remove other impurities left from soap or bleach, sterilize the tank by rinsing using boiled water. Another option for sterilizing the aquarium is using a vinegar mix to clean it. Prepare the solution in the ratio of 1:1. It kills any bacteria and algae left inside the tank. 

3. Set up a gravel base

Use a 1-inch layer of pea gravel to set up a base at the bottom of the aquarium. Pea gravel provides adequate drainage in the tank. It also holds water through the sand to provide humidity throughout the plants. 

Ensure that the gravel covers all points of the bottom layer. You can also use pebbles in place of gravel, they are affordable, and you can find them in any outdoor garden.

4. Add coarse sand over pea gravel

Add 3-4 inches of coarse sand at the top of the pea gravel. Sand being the poorest water drainage soil, it drains excess water to pea gravel. Coarse sand enables the plants and propagated cuttings to remain moisturized and protects the greenhouse plants against bacteria.

5. Add rooting hormone

To enable the roots to grow faster and healthier, add rooting hormone on top of the soil. You can get them at your local warehouse within your area. Using the directions and instructions provided in the package, add the appropriate amount of the liquid or powdered mix. 

6. Plant and grow your desired plant

After all the above steps are done, your greenhouse aquarium is ready for planting. You can decide to plant seedlings from scratch and watch them grow slowly. If you want to plant seedlings taller than the others, there are two ways.

Grow tall plants in the middle of the aquarium and short plants to surround the aquarium. Or, grow the tall plants at the back and short plants at the front, depending on the lighting. These will allow adequate lighting to reach all the plants. 

While planting, use a small spoon or your fingers to dig the holes. Place the plant inside the hole and cover its roots carefully as you pat the soil. The space between each plant in your greenhouse aquarium should be 3-4 inches.

7. Cover the aquarium

Using the glass that comes with the aquarium, cover the top of the aquarium. It helps to keep maximum humidity for the terrarium plants and cuttings. 

If you don’t have the glass cover, you can use any other glass or a plastic paper wrap. Ensure that the glass or paper wrap has adequate ventilation. If it does not have proper ventilation, make holes at the top corners of the plastic wrap or glass.

8. Install proper lighting

All types of plants require the light necessary for photosynthesis to germinate. Standard aquarium fluorescent light is the best for greenhouse aquariums. The location of your greenhouse aquarium will determine the amount of light it needs. 

If you put the aquarium near a window or veranda where it can receive direct sunlight, you do not have to provide artificial lighting. But, if it is situated on the dark side of the house, you need to give the plants artificial lighting. 

Once you are done with the above process, your greenhouse aquarium is ready to decorate the house. Every time you plant or see the propagated plants grow their roots, add more coarse sand and pea gravel to the tank.

What can you grow in a fish tank aquarium?

You can decide to plant any seeds or plants in a fish tank aquarium. If you follow the above steps, what you choose to grow will have proper drainage, ventilation, and lighting. 

The following are plants that you can grow in a fish tank aquarium.


Herbs are the most suitable plants to grow in an aquarium. Some examples of these herbs include; oregano, chives, parsley, coriander, mint, and basil. The challenge is that they require high air humidity. You will need an open-top aquarium to contain the moisture necessary for herbs. 

Some herbs are edible. They can save you grocery money. You can get fresh ingredients just from the greenhouse you made from an aquarium. 

If you want to grow one type of herb, that’s good because they will require the same conditions. But if you want more than one plant, ensure that they share the same growth conditions. 

You can pair some of the following plants in the same greenhouse:

  • Basil and oregano
  • Basil and cilantro 
  • Thyme and sage


Seedlings are also suitable for a fish tank aquarium. Examples of seedlings to grow in a fish tank greenhouse are onions, cabbages, tomatoes, and peppers. Plant the seedlings and allow them to germinate into plants. 

After about six weeks, transfer them to the farm where they are to grow into bigger plants. Seedlings require different growth conditions. Therefore, research individual seedling requirements to give your plants the best care.

Propagated plants

You can also grow stem-propagated plants in a greenhouse. Most people push the stems on the substrate and allow them to germinate into new plants. With propagation, you must carefully cut the stems shoot from the mother plant and stick them into the soil.

Examples of propagated plants grown in a fish tank aquarium include rosemary, thyme, and mint for kitchen herbs use. You can also grow hibiscus and roses in your terrarium for decoration purposes. 


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