Sounds like your garden soil needs a make over. Add three to four inches of garden compost to your raised bed and work this into the soil as best you can. It will take until next year to really improve your soil so meanwhile fertilize your yellow plants with a complete plant food such as liquid Miracle Gro for quick results and add Osmocote around the young plants for slow release nutrition that will feed all summer. Remember to feed your soil each fall or spring by adding compost or organic matter, Keep Growing, Marianne Binetti