Vegetables and herbs can suffer from various problems due to high humidity, high heat, too much/too little water, etc. Too much water can cause sage leaves to yellow and form brown spots, but so can high temperatuers, etc. Sometimes squash gets downy mildew, powdery mildew, or white mold. Tomatoes can also get white mold, powdery mildew, root rot, etc. For some disease information, see:
http://www.ipm.ucdavis.edu/PMG/GARDEN/VEGES/squash.html
http://www.ipm.ucdavis.edu/PMG/GARDEN/VEGES/tomato.html
http://vegetablemdonline.ppath.cornell.edu/factsheets/Cucurbits_PM.htm
In general, make sure not to waterlog the soil, and check the drainage at the bottom of the containers--be sure the drainage hole(s) are not blocked. Temperatures might get very hot if your containers are on asphalt, so a shade cloth during hot afternoons might be helpful, or positioning them to get partial shade in the afternoon. You can also add a little mulch on the soil surface--but keep the mulch from directly contacting the main stem of the plant, in case the humid air might encourage disease. Avoid overhead watering, which can encourage disease--water the plants at the base, or use self-watering containers.
If you could set up a fan to blow gently on the plants for a few hours each day, that might help to avoid diseases in humid weather. The more (gentle) air circulation, the better.
Vegetables and herbs can suffer from various problems due to high humidity, high heat, too much/too little water, etc. Too much water can cause sage leaves to yellow and form brown spots, but so can high temperatuers, etc. Sometimes squash gets downy mildew, powdery mildew, or white mold. Tomatoes can also get white mold, powdery mildew, root rot, etc. For some disease information, see:
http://www.ipm.ucdavis.edu/PMG/GARDEN/VEGES/squash.html
http://www.ipm.ucdavis.edu/PMG/GARDEN/VEGES/tomato.html
http://vegetablemdonline.ppath.cornell.edu/factsheets/Cucurbits_PM.htm
In general, make sure not to waterlog the soil, and check the drainage at the bottom of the containers--be sure the drainage hole(s) are not blocked. Temperatures might get very hot if your containers are on asphalt, so a shade cloth during hot afternoons might be helpful, or positioning them to get partial shade in the afternoon. You can also add a little mulch on the soil surface--but keep the mulch from directly contacting the main stem of the plant, in case the humid air might encourage disease. Avoid overhead watering, which can encourage disease--water the plants at the base, or use self-watering containers.
If you could set up a fan to blow gently on the plants for a few hours each day, that might help to avoid diseases in humid weather. The more (gentle) air circulation, the better.