It is possible that your soil is too acid, or that all that Miracle Grow has acidified it, and the onions do not like it. I am no expert with continuous fertilization, I fertilize tomatoes exactly twice, and IMHO only cabbage and collards need continuous fertilization.

I am just west of Detroit, and I have long learned that the only way to counteract a year like this is to grow more roots and more leaves and fewer fruits.

The onions were possibly planted way too deep.

I'm not sure why you're concerned about fertilizing now. If whatever you're spraying hasn't hurt the plants yet, it probably won't hurt them now. The important thing about fertilizer is that you should know what it contains, in terms of nutrients. Different plants have different nutrition needs.

Growers of trees and perennials don't want to do late fertilization because they fear it will push new growth that won't survive a harsh winter. Your plants are all annuals, so you don't have this problem. Your green tomatoes will continue to ripen off the vine if you pick them at the end of the season.

I'm going to fertilize then, and not give up on my onions. Thank you both!

We ripen green tomatoes two ways. Wrap each one in newspaper and store inside or if they have a slight blush ripen them on a sunny windowsill.

Number one, not everything in the garden should have the same fertilizing schedule.

Number two: Not everything in the garden should be fed with the same fertilizer.

For example, onions, cabbages, .. leafy greens need mostly Nitrogen, some potassium very little or no Phosphorous .

Another point: Since you have a short and cooler growing season, fertilizing tomatoes at this stage is not going to do any good, as far as ripening the fruits are concerned and instead it will cause more foliage growth, more news flowers, etc.

You may want to consider an organic approach to fertilization. It has several advantages, which I will summarize: 1.) It is milder than chemical applications and so is far less likely to burn your plants or cause other damage. 2.) You can incorporate sufficient fertilizers into the soil before you plant, and not need to fertilize again until you harvest and replant again. This is because the majority of organic materials are relatively slow release. 3.) The addition of organic materials into your soil builds up humus, which super important for over all plant health.It keeps the soil loose and aeriated, retains moisture, promotes worm growth, provides trace minerals, and provides many other benefits.

A good source of information about organic gardening techniques can be found at http://www.alan-chadwick.org

Click on the tab labled techniques to learn about the culture of various plants, build highly effecient raised beds, make compost, and much more.

Hope this helps.

Here is a link that might be useful: Alan Chadwick