
I was told not to use Miracle Grow as it adds too much sodium to an already salty soil that we have here. I have tried others recommended by plant stores but they require mixing with the soil and are difficult to apply once the garden is established. I like the spray on method that Miracle Grow uses. Any suggestions for a good fertilizer to use?

Other quality inorganic fertilizers you can use include Osmocote and Peters as well and they do not contain sodium either. What is more important than the manufacturer to promote flowering is the fertilizer ratio or the numbers associated with that fertilizer. That is what you need to focus on.
For flowering plants the middle number needs be higher than the first and third numbers. For nonflowering plants the first number should be higher than the second and third number. When focusing on reducing stress then the last number should be the highest.
Try to use a fertilizer that has all three numbers present (no zeros) but use fertilizers which have ratios, as I suggested, promoting specific types of growth.
Other problems with marigolds during the summer include spider mites. The biggest problem related to the decline of nondesert type annuals in our desert climate and soils is the lack of adequate soil preparation at the time of planting.