The plants are in an 8' wide by 3' high by 2' deep box I built on my deck. A bench seat overhangs the front and slopes slightly away from the box, so only about 2/3 of the soil surface is exposed to rain.
The box is on feet to keep it off of the surface of the deck, and has 20 or so 1 cm holes drilled in the bottom. It is filled with dirt, the top 5-6 inches being newly-installed "vegetable garden soil".
The box previously had trumpet vines in it, growing up a trellis. The vines didn't survive a recent cold winter, and I periodically remove some of the dead vine, break it into small pieces, and drop it into the box.
After planing the zucchini seeds, I initially watered thoroughly every few days. When I saw the leaves not looking right, I thought the culprit might be over-watering. I scaled back, but the rain took over. We are finally getting some sunny days, so the soil will be dry by tomorrow for the first time in 3-4 weeks.
Rainfall in the area tends to be pretty acidic, but the soil at the surface is new. Thus, I would think the pH should be pretty close to the pH of the store-bought soil. I haven't tested it, though.
