12 Plants That You Can Grow in Cinder Blocks

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Cinder Blocks are a standard material on many building sites. But, with a bit of creativity, they can be used in many different ways. Some of these creative people are giving new life to their blocks by growing plants in them. Here are some plants that people have been growing:

  • Radishes
  • Carrots
  • Lettuces
  • Tomatoes (certain types)
  • Beetroot
  • Onions
  • Micro-greens
  • Spinach
  • Chard
  • Scallions
  • Other leafy greens  
  • Flowers (many varieties)

What Plants Grow Well in Cinder Blocks?

Cinder Blocks are standard for people looking to build a raised bed, which means they need to know what you can grow in them. As we know, the plants that grow the best in cinder blocks tend to have smaller roots. 

As well as vegetables, you can grow a wider variety of plants. Flowers add a burst of colour to a garden and contrast perfectly with the grey colour. Herbs are another perfect plant to grow in a cinder block and provide enough support and warmth for your plants to flourish.  

If you’re still unsure about a plant, have a look at how big their roots grow, and make your decision, remember the smaller, the better. Also, if you know what plants do well in a typical raised bed, they should do well in a Cinder Block.

Are Cinder Blocks Safe for Plants?

There has been some thought behind using cinder blocks, as people have been concerned about how much of the materials inside cinder blocks may leach into the surrounding soil.

Some cinder blocks contain something called ‘Fly Ash’, a by-product when you burn coal. This ‘fly ash’ may mean that heavy metals or hazardous materials are introduced into your plants and then into you (if you consume the plant).

The University of Maryland says that,

“cement blocks, concrete blocks and cinder blocks are made using cement, and this cement contains fine materials such as sand or small pebbles. There is often fly ash added to these blocks.”

The university has advised that if people want to use cinder blocks or other similar materials, then a reasonable precaution would be to seal the blocks with a safe sealant before use. A suitable sealant to use would be polymer paint, as this doesn’t get affected much by the moisture in the soil, but whatever you use will depend on you and your materials.

The sealant you use will also provide a waterproof barrier to your raised bed, allowing the soil to remain moist for longer as the water isn’t drawn away as quickly as it may have been.

Can Tomatoes Be Grown in A Cinder Block?

Yes, certain types of tomato love cinder blocks. These types of tomatoes are known as determinate varieties and love the warmth of the blocks.

You can get the right amount of support that the plants need from the cinder blocks as you get enough depth in soil for their roots to grow and spread.

The other types of tomatoes, known as indeterminate varieties, don’t do as well as they need a more robust support system and need pruning to keep them looking fresh and healthy.

You can keep your tomato plants healthy by making sure they are exposed to the right amount of sun, are watered regularly, and their fruits and leaves are clear of the ground.

The appropriate size of the cinder block is also something you need to consider when planning your garden. You will need about five gallons of soil to provide enough support for your tomato plant, with the bottom being well connected with the soil below.  

Can You Grow Carrots in A Cinder Block?  

Carrots are perfect for growing in your cinder blocks. You can grow any carrot, and you should always get a nice shape carrot at the end. The shape cannot be guaranteed, though.

Like many other plants, you need to make sure you have the correct size cinder block for growing carrots. Carrots typically require around two or three gallons of soil to grow well.

You can try carrots that grow a lot longer than regular carrots by stacking cinder blocks to make sure they can reach through the ground below them.

Carrots grow well when they are weed-free, which cinder blocks are perfect for. The fact that carrots don’t like being disturbed make them perfect for these blocks as you don’t need to do much to them. They don’t need extensive watering and are drought resistant, and the fact that cinder blocks retain water well helps them out. In fact, they love them!

Can You Grow Flowers in A Cinder Block?

Yes, flowers are perfect for growing in cinder blocks. The variety of colours add so much character to the blocks and your garden. The flowers are also perfect for attracting bees to your garden, which will bring your garden to life.

You need to pick the right flowers, of course; flowers with small root systems work the best, similar to any other plant. Some flowers that do well in cinder block are:

  • Fushias
  • Petunias
  • Bacopas
  • Lobelias
  • Geraniums
  • Osteospermums
  • Verbena
  • Pansies

You can find many more flowers available that would grow well in cinder blocks, but here are just a few. Some may be bigger flowers than others; they should all love their new home.

Advantages and Disadvantages Of Cinder Blocks.

AdvantagesDisadvantages
Weed Control: Cinder blocks will naturally inhibit the growth of weeds, which can take work if they are out of controlNot Enough Support for Some: Some plants need some more support, and the cinder blocks may not provide the proper support.
Provide Warmth: By retaining heat in the soil, plants used to warmer climates like tomatoes get an extra boost due to the warmth.They Can Be Too Hot: If you are growing in an area that gets a good amount of sunlight or live in a hot climate, then the heat from the blocks may be too much for some plants to handle.
Easy to Water: The holes in cinder blocks make it easy to provide enough water for your plants to thrive.Affect Soil pH: As cinder blocks are concrete, they have a low pH, which may affect the soil and slow growth.
Cheap and Cost-effective: Being low cost, they provide an excellent planting option to those on a budget. You may even find ones for free.Difficult to Amend: Once your plants have been planted, the soil can be difficult to amend or add fertilisers. You may have to dig them up, which may affect growth.
Provides Support: The blocks are perfect for any plant that needs extra support when growing. They can provide a framework to grow up and keep the leaves off the ground.Only for Small Roots: Plants with deeper or larger roots will not grow well in cinder blocks, as they are best for small rooted plants or those with slow spreading roots.  

Conclusion

When looking at the advantages and disadvantages side by side, the advantages seem to outweigh the disadvantages that you get. The Cinder blocks do provide a good option for many people.

You can grow many plants within cinder blocks, and they can be an excellent way to create a garden within a limited space or a limited budget. Once you know what you are doing, they can transform any space you put them into.

Although some plants do not do well, if you choose the right plants and make a suitable construction, you can have a beautiful garden.