What are the best joint fillers for granite outdoor flower boxes?

Granite outdoor flower boxes add elegance to any garden, but over time, the joints between the stone slabs can crack or deteriorate. Choosing the right joint filler is essential to maintain durability and aesthetics. Here are the best options:

1. Polymeric Sand – Ideal for filling gaps between granite slabs, it hardens when wet, preventing weed growth and insect intrusion.

2. Epoxy-Based Fillers – Highly durable and weather-resistant, these fillers bond tightly with granite, ensuring long-lasting repairs.

3. Silicone Sealant – Flexible and waterproof, silicone is perfect for areas with slight movement due to temperature changes.

4. Urethane Caulk – A strong adhesive that resists cracking and UV damage, making it great for outdoor use.

5. Mortar Mix – A traditional choice for a seamless look, though it requires more skill to apply evenly.

For best results, clean the joints thoroughly before application and choose a filler that matches your climate and maintenance preferences. Regular sealing will further protect your granite flower boxes from moisture and wear.