Another pinner says - I have made these before - so easy! Lowes sells the 4 to 6" round PVC pipe with holes already drilled. Purchase an end cap, fill with rock, soil, and plant. I will often put these in the center of a very large pot to stabilize, and add amazing height and color to a container that has trailing plants (no end cap or rock needed if you are placing in a container)
Did you know that you can grow another complete celery stalk from the bottom piece that you cut off and throw away? This is new to me, too, but I have been doing it this year and it works! I use a lot of celery when cooking and I hope to save quite a bit by re-growing it throughout the spring and summer.
Add 1 tsp. of liquid food coloring to 1 cup of water. Drizzle the colored water onto the soil surrounding the base of a plant. Wait 24 hours for the water to absorb. Apply another identical dose if the color change was not sufficient.