How to plant in new concrete pots
We have new concrete pots or urns for our church. They were stained by the retailer. I've taken on the job of planting in them, but I'm hearing different advice about concrete pots. Do they need any prep work before planting in them?
I heard you need to apply a concrete sealer to the inside the pot. It would help it not to absorb water and lessen the chance that it would crack in cold weather. Then add the pebbles and sand for good drainage.
Then another person suggested putting in a heavy mil vinyl garbage bag into the pot; punch a hole in the bottom of the bag, add the pebbles and sand.
An idea I had was to find a black plastic pot like the ones used by nurseries and insert that in the pot. Then add the pebbles, sand and plants.
What worked for your concrete pots? And how many inches of pebbles/sand? The urns stand 20-22" high.