Discussions

This is our second year of gardening, we have much to learn.  
 
Both last year and again this year we have found that our plants and more so the broad leaf seem to get a grey/white powderish film on the leaves and then it is like the leaf is suffocated and the plant dies off...this seemed to start in mid to late season and after watering with city water.  
 
what is there that I can do for next gardening season???? Help please!!!

I have 4 rain barrels that i use to collect water for my gardening needs. I have one at each eavestrough downspout. Cover your barrels with screen to help prevent mosquitos. You can use wood or pallet boards strapped around your barrels to make them look nicer.  
Also a small electric water pump can be purchased to water your plants- just put the inlet hose to your rain barrel of choice and connect garden hose to the outlet side. Places like "Princess Auto", TSC or Home Depot may have these pumps in stock.  
I'll be upgrading to 1000 liter totes for next year. (A bigger garden next year).  
 
Check out pinterest for other rain collection ideas, or off-grid living websites for inspiration. It may not be the water from the city that is leaving a residue. Also inspect/consider other environmental aspects such as proximity to industry or traffic, high dust area, soil alkalinity or salinity, fertilizer application, etc...  
It may or may not be the treated water- or the hardness thereof, but using rain water will maybe help alleviate your concerns.  
Also you may save on your water bill...

We collect rain water for our plants as well but still had the same thing happen with our zucchini plants.

My first guess is powdery mildew. It likes to attack all kinds of plants, and does really well on broadleaf plants.  
 
Any direct relationship to water source is unlikely, although I do prefer rain water myself. The chlorine in the city water should be well dissipated by the time it reaches your home, but if it is still fairly potent it can cause the leaves to start dying at their periphery, moving inward, as the chlorine accumulates.  
 
Here is a farmer's almanac article on powdery mildew: http://www.almanac.com/pest/powdery-mildew  
 
Note their recommendation to not compost the diseases material, it will just encourage the disease over time. Destroy infected materials.

I had it too all through my zucchini (but not the pumpkin, oddly). In my experience it seems worse during wet mild summers like the one we just had. I've had mixed success spraying the leaves with soapy water as soon as the infection appears.

Powdery mildew. My zucchini had it this year and spread to the cucs. I mixed some milk and water together and sprayed the leaves. I might try soapy water if happens again. I use mostly rainwater, I don't think the type of water makes a difference

Thank you for all your help, my daughter suggested sulfur powder as well.  
 
I will try everything next year if it happens.

So, how should I destroy/dispose of the infected plants? I obviously wouldn't put them in my yard compost. I'm assuming putting them in the city green bin is a no-no too.  
 
Can I just send them to landfill then? Or am I better burning them?

It is without a doubt powdery mildew. It is a relatively harmless disease and does not require any chemical control. Shade does exacerbate this disease, but little, if any damage to the plant occurs. Culturally, you can try to reduce the amount of shade and reduce moisture content. No need whatsoever for special disposal of leaves, etc.

Would this be what I get on the grass in my back yard? Also seems to be late in the season and in shadier areas.

seen it on grass, but JackAzz is right. https://www.gov.mb.ca/agriculture/crops/plant-diseases/powdery-mildew-humidity.html The only advice for watering is to water the soil, not the plant. In my experience plants in shade or shelter are more susceptible to infection.