planting under a patio

Question

I have a concrete patio. I want to cut a couple of holes in the concrete and plant some color. First hole cut, excavated hole 14″ x 12″ x 24″ deep. Planned to fill with good compost/planting mix then plant the color. Now the problem: The material removed is damp clay and I’m thinking that these holes may eventually fill with water, be unable to drain and the plants will drown.

Answer 1

You are probably correct, especially because the clay soil is probably compacted because it's been under a patio.

These articles have some suggestions:

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/yard-drainage-problems.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/yard-drainage-problems.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-to-improve-clay-soil.htm

You could also consider plants that don't mind a poorly drained environment. However, you'll also need to make sure these plants don't dry out too much on hot days.

https://www.gardeningknowhow.com/ornamental/water-plants/wgen/water-tolerant-plants.htm