How to Seal Concrete Planters Without Harmful Chemicals

If you love using concrete planters in your home or garden (like I do, obviously!), sealing them is a crucial step, especially if you want them to last longer and maintain their beauty. But many commercial sealers are packed with chemicals that can harm plants, affect soil health, or release strong odours.

Today, I’m sharing eco-friendly ways to seal your concrete planters without using harsh chemicals — ideal for plant lovers, natural home enthusiasts, and anyone working with handmade or DIY planters.

How to Seal Concrete Planters Without Harmful Chemicals

Why Seal Concrete Planters?

Concrete is porous, which means it can absorb water, soil, and even stains. Sealing helps to:

• Prevent water from seeping into the concrete

• Avoid surface cracks and moss growth

• Keep soil and minerals from leaching into the concrete

• Protect indoor surfaces from staining if used inside

If you're placing your planters outdoors, sealing is especially important during rainy seasons or winter months.

What to Avoid: Common Chemical Sealers

Many popular sealers contain:

• Acrylics

• Solvents

• Silicones

• VOC-heavy resins

While effective, these can release fumes, harm plants, or create unnatural finishes; not ideal if you're going for a more organic look or using the planter with edibles, herbs, or sensitive plants.

Eco-Friendly Sealing Alternatives

Here are several planet-friendly ways to seal your concrete planters naturally:

1. Beeswax and Olive Oil Mix

A traditional, non-toxic method that’s safe for indoor and outdoor use.

How to apply:

• Melt 1 part beeswax with 1 part olive oil

• Let it cool slightly, then rub it onto clean concrete with a cloth

• Buff until it creates a soft, water-repellent layer

• Reapply every 3–6 months

Note: This adds a slight sheen and darkens the concrete slightly.

2. Natural Linseed Oil (Raw, Not Boiled)

Raw linseed oil penetrates concrete and hardens slowly, creating a natural barrier.

How to apply:

• Use a clean brush to apply a thin coat

• Allow it to soak in for 24 hours

• Wipe off excess and let it cure for 2–3 days

• Repeat once or twice for the best effect

Make sure it's raw and solvent-free.

3. Food-Grade Mineral Oil

A simple, plant-safe option, perfect for indoor planters or decorative use.

How to apply:

• Apply with a cloth

• Let it absorb for 1–2 hours

• Wipe off any excess

• Reapply every few months

This works best for decorative or dry plant arrangements (like succulents or cacti).

Example: Look for mineral oils, such as those available on Amazon.com. They are widely available and are commonly used for chopping boards and butcher blocks, making them suitable for planter use as well.

4. Eco Concrete Sealers (Water-Based, VOC-Free)

If you're looking for a more durable option, some small-batch suppliers offer water-based concrete sealers that are:

• VOC-free

• Non-toxic

• Pet- and plant-safe

Check labels for: low odour, food-safe, and biodegradable formulas.

Prep Tips Before Sealing

• Clean thoroughly – use mild soap and a brush to remove dust, oils or mould

• Let dry completely – moisture can prevent the sealant from working

• Sand lightly (optional) – gives a smoother finish and helps oil absorb better

Best Uses for Sealed Concrete Planters

Eco-sealed planters are ideal for:

• Indoor pots on wooden or stone surfaces

• Outdoor garden pots exposed to rain

• Herb gardens where you want to avoid contamination

• Gifts or handmade products for eco-conscious buyers

Bonus: Pair This With Concrete Repairs

If you’re sealing a planter after fixing cracks or chips, check out my concrete repair tips for planters and pots — it’s a great step-by-step guide to help restore older pots before sealing them naturally.

FAQs

1. Do I have to seal every concrete planter? Not always. But sealing helps protect the surface, especially for outdoor or herb planters.

2. Will sealing change the look of the concrete? Yes, slightly. Natural sealants, such as oils or waxes, may deepen the colour or add a soft sheen.

3. How often should I reapply natural sealants? Every 3–6 months is ideal, depending on the sun, water, and use.

4. Can I still drill drainage holes after sealing? Yes, reseal around the hole if needed to protect the edges.

5. Are eco-friendly sealants waterproof? They’re water-resistant rather than fully waterproof — perfect for everyday use, but not for prolonged exposure to standing water.

Final Thought

Sealing your concrete planters doesn’t have to mean using harsh chemicals. With a few natural ingredients or plant-safe sealers, you can protect your pots, extend their life, and stay aligned with your eco-conscious values.

Looking for handmade planters or trays to use with your favourite plants and rituals? Explore my collection here.