jardinier_79,

As you described above, the rains are exactly why your plant's aren't showing signs of rapid growth. If the powdery mildew does not go away, you will have to use a copper spray to help stop the spreading.

Ron

Why do your outdoor containers have reservoirs? Unless they are self watering pots, they should drain freely. With all the rain we've had, plant reservoirs and saucers are a death sentence for outside containers.

As for powdery mildew, it is very difficult to cure. The best practice is prevention. Zucchini grows so fast, you could start over, but you would need fresh soil, and you would need to treat them from the beginning with something that will prevent PM. On the other hand, your plants are young enough and appear to be only lightly infected, so you may be able to keep it under control. I don't think copper spray is the best choice. Here is an excellent article discussing many organic methods for preventing/slowing down PM. It is specifically for hydroponic growing, but has an excellent rundown on sprays. I have used milk and serenade with some success.

Here is a link that might be useful: How to beat powdery mildew

Ohiofem,

As the OP mentioned, they go out frequently to dump the excess water out of the reservoir when it rains. I would say that is a good idea as opposed to never dumping it out which will kill the plant. There are a lot of gardeners that grow this way because they don't want to water every day or multiple times a day.

Great link Ohiofem, thanks.

Ron

Thanks for all the info! We had a couple of dry days, the soil dried out, and my plants look like they're on the way to zuke proliferation. Thanks again!

Sometimes in my garden (I live in NY) we can have a typical NY rainstorm and my pots can become waterlogged - and it can take sometime for my plants to recover (if they don't die). I got really frustrated but started using this product called Brolly (www.brollyusa.com) and its helped a lot. It has a canopy that you can attach during excessive rain and remove it once the rain has stopped. So simple but really helped. Hope this helps - good luck!