How To Seal Concrete Planters Effectively

Sealing Concrete Planters

Concrete planters are beautiful additions to our homes and yards. They are extremely robust and can take many pretty shapes and sizes. However, you want your concrete planters to last a very long time. That is why it is important to seal concrete planters before you plant in them. Otherwise, they will be prone to damage and worse, damage to your plants.

Below, we will list the necessary steps for you to know how to effectively seal your concrete planters.


How to Seal Your Concrete Planters


Step 1 – Clean Planter Thoroughly

Before you seal the planter, it is important to give it a good cleaning. Set the planter outside in an open space. Hose it down with water 3 times throughout the day. Let it dry before you do it again. This helps leach out the excess salts and alkalinity.

Next, make a simple homemade solution consisting of warm water and liquid soap in a bucket. Mix the solution. Get a sponge or brush. Then clean the entire planter with the solution by scrubbing thoroughly inside and outside. Effectively scrub down any dirty areas of the planter.

After it has been efficiently cleansed, hose it down with water one more time and then let it dry. Repeat the process with your homemade solution if the planter still appears dirty. Before you proceed to the next step, your flower pot should look very clean.


Step 2 – Seal Your Concrete Planter’s Exterior

So your planter is now dry and ready to be sealed with a concrete sealer. Place your planter upside down on a surface that you don’t care to get sealer on – maybe a piece of cardboard or tarp.

Now, apply your first coat of sealer with a paint brush on the exterior of the planter, nice and evenly. Make sure you get everywhere including the bottom.

Once the planter’s exterior is fully sealed, bring it inside your garage or another safe location with good ventilation and let it dry overnight.


Step 3 – Seal Your Planter’s Interior

Your first coat of sealer on the exterior is now dry and now it’s time to seal the interior. Put the planter back in its position and efficiently seal the inside of it using nice and even strokes. Again, let it dry overnight in a safe location.

It is not recommended, but if you want you may repeat Steps 2 & 3, in case you accidentally missed some spots the first time. This way, you have 100% sealed all of the planter.


Your planter is now effectively sealed and should not be prone to any of the damage described below.

You are now ready to plant some gorgeous flowers in your planter!


Why Should You Seal Concrete Planters?

If you do not seal your concrete planters, then a couple things will happen, all leading to the degradation and destruction of the concrete as well as damage to the plants.

Concrete is high in alkalinity which can leach into the soil and then damage plant roots and stunt the growth of plants. Alkaline soil is commonly referred to as “sweet soil” and consists of a pH level above 7. It generally contains a large amount of sodium, calcium, and magnesium.

The availability of nutrients is limited in alkaline soil because it is less soluble than acidic or neutral soil. Therefore, your plants will have a difficult time obtaining their nutrients, staying healthy, and growing.

Next, concrete is porous, meaning that water will evaporate quickly out of the soil, thereby drying out the plant roots. Furthermore, the porosity of concrete means it is inclined to absorbing salts and moisture from the air which makes it prone to forming cracks.

Slowly, these cracks will multiply and cause degradation of the concrete. Cracks permit water to seep inside the planter. The water will heat up and cool down causing it to freeze and thaw; compacting and expanding. Eventually, this produces unsustainable pressure that creates more cracks and ultimately the complete destruction of the planter.

Lastly, lime leaching may occur with unsealed concrete planters. This is known as efflorescence. This is when you notice white powdery substance on the surfaces of the concrete. You may have seen this on your patio or driveway if it was poorly sealed.

Lime leaching is caused by vapor traveling through the concrete slab, bringing soluble salts to the surface of the concrete.

All in all, it is important to seal your concrete planters for the above reasons. You want them to last many years to come as they should. Yes, they do require more preparation and maintenance compared to other flower pot types, but they are definitely worth it.

If you have any questions or concerns, please leave us a comment below.

About Sarah Morrison

Hello there! My name is Sarah Morrison. Thank you for coming to my website and I hope I was able to help you. To tell you a little bit about myself – I am an avid writer, enjoy horseback riding and nature, love gardening, and as you can probably guess from my content on this blog, I fell in love with the outdoors at a very young age. Now that is what I write about – specifically things you will love for your garden and how to make your garden absolutely fabulous. I really love to blog about ways or ideas how you can make your garden, flowering, and landscape areas more beautiful and elegant. Anyways, thanks for stopping by and leave me a comment below on any of my articles to get in touch.

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10 Comments on “How To Seal Concrete Planters Effectively”

  1. Good morning! I am just getting started on making concrete planters for outdoor use. Any information would be greatly appreciated.
    I was wondering a few things about the concrete sealer. What is the most affordable sealer on the market?
    Also, how long can I expect the sealer to last? Should the sealer be reapplied once a year or does it last longer?

    1. Thank you for your comment Kimberly. Personally, I think you should reapply sealer to your concrete planters once a year just to be safe. Factors such as the type of concrete sealer, weather inclement throughout the year, and other damage may all play apart if your planter needs to be sealed again. So just reapply once a year to be safe. That is what I do.

      As for the most affordable sealer and the most effective, I personally like this brand. It works for all my concrete surfaces.

  2. I am reading that you must wait a minimum of 60 days to fully cure the concrete before sealing. Is this necessary? Seems like a very long time to wait. Is this true for all concrete sealers?

  3. Thank you so much for taking the time to answer my questions! I’ll have several more if you do not mind.
    I was wondering if it is necessary to seal the inside and outside of the concrete pot if I plan on painting the outside.
    This is what I’ve been doing and I think I am taking unnecessary steps.
    1. After pot is made I soak the pot for a minimum of 3 days
    2. After drying from soaking I seal inside and out
    3. The pot is then primed…mainly the outside
    4. I then paint
    5. After I paint I put a polyurethane coat so that the paint will last

    Do you notice any unnecessary steps I am taking?

    Also, I’ve been playing with the ratio of cement and sand. I find that there is too much sand in the mortar mix so I add cement to make it harder. I see ratios on the web of 1:1, 2:1, and 3:1…sand to cement. Is there a particular kind you like to use so that you do not have to continually mix the sand and cement?

    1. Hi Kim, I would say you are doing everything fine! The most important part is applying the sealer after the pots are dried. After the pots are sealed, you are pretty much fine to do whatever you please with them. As for the concrete mixture, I don’t think I can help you out there as I mainly buy concrete planters and then seal them myself for extra caution even though some manufacturers state they are already sealed. However, in my opinion a lower ratio of sand to cement would be better. Hope this helps!

  4. thank you for your advise. it was a very important guide for me this time. so, i have 1 question.

    what type of sealant should i use for my pots? is there any difference in those sealants from market.

    thanks much

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