Question
I read about the use of neem oil to deter pests and fungal diseases on vegetables (tomatoes and cucumbers in my case).   I am mixing 100% neem oil according to the directions on the bottle which recommends 1/2 teaspoon of neem oil and 1/2 teaspoon of non-antibacterial dishwashing soap per quart of water.  I shake the mixture while applying and try to get the undersides as well as top sides of leaves.  However I do not see that the leaves get "shiny" after application, as people report on various web sites.  The other concern I have is that usually within a day or two of applications we have a thunderstorm in my area.  I'm wondering if I am applying the neem oil in enough concentration to be effective, and how often I should re-apply it with and without a subsequent rain shower.j4l

Answer
Dianne,

Following the instructions for application is probably the best starting point.  I would reapply the oil after every rain, and even daily if your plants are getting dewy at night as any moisture will probably remove most to the oil.  It may take some time for the plants to bounce back, and they may never depending on how bad the pest and disease is.  If there is no help for a plant, pull and destroy it so as not to affect the healthy ones.  You can always replant something else and try again next year with the tomato or cucumber.

Make sure you amend and fertilize your soil every year, healthy soil is the best way to keep pests and disease out of your garden.  I have a great little ebook http://www.your-vegetable-gardening-helper.com/why-is-soil-so-important.html for tips on making and maintaining healthy garden soil.

Hope this helps.  Please let me know if you have any further questions.

Catherine
www.your-vegetable-gardening-helper.com