Question
QUESTION: Hi, I'm in the Midwest, and need recommendations as to when, what, and how to correct my soil test levels for my perennial gardens.  The last couple of years I have had numerous insect problems, fungus problems, and wilting/dying plants.  Many although have thrived.  This was the reason for me testing my soil.  My pH level -7.0; nitrogen-depleted; phosphorous-deficient; and potassium-adequate.  Other than applying an organic compost this fall, I'm confused what else to use, and if more than one product, if they can be used with each other.  I really would like to start improving the soil now rather than waiting until next spring.  I would appreciate any recommendations and guidance you could give.  I really am ready to give up my passion for gardening if I cannot help my plants be healthy and happy.  This is way too frustrating considering the time, money, energy, and love that I devote to my flowers.  Thank you for any advise you can give me.

ANSWER: Hi Sue, When it gets a little cooler, I'd lift and divide the perennials that are doing well. Then I'd cover the area with an inch or two of compost or finely ground pine bark and till it thoroughly.  Then replant your perennials.  For most flowers, I strive for a pH around 6.2 to 6.5.  Your pH will drop some when you start fertilizing after you plant. I'd use a 12-6-6 or similar fertilizer for your first two feedings and then move to a lower nitrogen, higher phosphorous fertilizer for the rest of the season.
Remember this...all perennials do not like the same conditions.  Some need better drainage, some need better air movement or they are prone to disease.  The English garden perennial bed you see in pictures is a lot of work and only looks that way for a short time.
When you go to your local nurseryman, tell him how much you want or don't want to work in the garden.  He can help you with perennials that require less care and are best suited for for your soil and climate.  Jim

---------- FOLLOW-UP ----------

QUESTION: Jim, Thank you so much for your guidance and help.  I do realize that all perennials don't like the same conditions, but I do my best to choose plants with similar requirements.  Would you recommend an organic compost, mushroom compost, or cow munure?  Would you please clarify if I use a liquid fertizlier or pellets?  Also, considering we are at the end of September, how many more times this season can I fertilize? If it was a fungus that some of my plants suffered from, will this prevent it from returning next year?  I do spend hours on the internet researching resolutions to my gardening problems, but never seem to come up with clear solutions, which is why I turned to you. I definitely want to do it all the right way, hoping for a positive outcome. Thank you for your guidance.

Answer
Hi again, I choose a soil amendment based on the soil to be improved.  If it's clay, I want a mostly a coarse product, like finely ground pine bark, ground leaves, etc.  I then add a little cotton burr compost or cow manure, but any fine compost will do. I want to use the clay, just separate it, so not more than 40% soil additive. If the the original soil is already in good shape and I don't need to improve drainage, then compost alone will do.
There is very little plant food in compost.  It is mostly texture.  It separates the soil giving pathways for new roots.  It does however feed the microbes which in turn, makes plant food more readily available.  So compost most definitely helps your plants when used in moderation. Use which ever is the most readily available and affordable.  
Fungal problems are associated with water.  Depending on the plant and the pathogen, water on the foliage, excessive soil moisture, improper drainage, etc.  I can't recommend a fungicide without knowing what disease you might have, so next spring, with the first sign of problems, take a sample to your local garden center, the whole plant with the roots and soil, so you can get the appropriate fungicide.
Liquid or granular fertilizer is strictly your preference.  The type of nitrogen is what's important.  Plants can't absorb organic nitrogen.  The molecule is too large, so it must be broken down into inorganic nitrate before the plant can use it, but you'll get great results with it. It's just a little slow. Ammonia based nitrogen is quick, has little residual, but is not available in cold ground.  Nitrate nitrogen is quick, has little residual but is available at any soil temperature. Ammonia or nitrate nitrogen will give a plant a quick burst of growth, which may or may not be best for the plant.  It's great for corn, not for tomatoes.
If you aren't getting the flowers you should, we'd bump up the phosphorous and back off the nitrogen.  
The only fertilizer I use in the late fall on perennials is 0-20-20 at 1 to 2 lbs. per 1000 sq. ft.  It's late for quick release nitrogen except on fall annuals like pansies, but a low dose of Plant-tone or Milorganite will not force any growth and may help struggling plants.  Jim