In May 2014, we planted snap beans, coneflowers, and milkweed for the first year of the garden since all of these plants are ozone sensitive. There were also snap beans we received from the US Department of Agriculture that had been bred to tolerate ozone. The tolerant beans and sensitive beans came in separate envelopes, and we planted each strain in separate beds.
The reason we chose to study these plants is because ground level ozone harms these plants at lower amounts in the air than the amount that will harm the human body. Therefore, we call these plants ‘early indicators.’ The ozone enters the plants stomata, which are pores in the plant that allow gas to enter and exit. Plants need to take in and release gases in order to make food for themselves through photosynthesis. Once the ozone enters the plant, it damages the plant from the inside. We can see some of this damage by tracking the amount of small black dots called stippling on the tops of the leaves, yellowing (chlorosis), and brown, dying parts of the leaf (necropsy).
When the coneflowers arrived, the soil they came in was rock hard. To loosen the soil and get the plants out of the plastic containers they were shipped in, we soaked them in a waiting pool. After being in water for a while, the plants slipped out of the containers easily when turned upside down. To make room for more plants, we dug holes in a triangular pattern. Imagine a lightning bolt drawn on the soil bed with holes at each corner. When transplanting, make sure to loosen the roots of plants with your fingers. We placed compost in each hole, followed by a plant, and then filled the area around the plants with soil.
We planted the milkweed in July 2014 in the same type of pattern as the coneflowers. The week after you transplant plants, you need to water every day so the root systems will develop.