Jericurl,
Sorry for taking so long to reply, I didn't want to bore anyone, but here it goes.
Just an FYI regarding the cardboard, it will breakdown, and the worms will help to process it much like the paper bedding used in some home worm farms, what you need to be careful of is the amount of nitrogen used up (from the soil) to break it down, the same thing goes for mulch used in flower beds, it is very pretty and helps to keep the moisture in during the spring and summer and the keeps the frost from damaging roots in the winter in cooler climates, but as it breaks down its "steals" nitrogen from the soil.
The good news is that most generic fertilizers contain some level of nitrogen, which will help to replace what is being used.
Do we all know how to pick out a fertilizer, how to tell what level of nutrients it contains the NPK?
Knowing this is extremely important, plants have different nutrient needs during different growth phases, for instance, during the initial growth phase, seedlings need not only nitrogen for green growth, but phosphorous for root development, cell division and development of new tissue, and Potassium aids in the uptake and movement of other nutrients in the plant, and so on, what is lacking are other vital micro and macro nutrients such as Calcium, Magnesium, Boron, Sulfur, Iron, Copper, Manganese, Zinc just to name a handful.
Most generic fertilizers only worry about providing the NPK - Nitrogen, Phosphorous and Potassium, think Miracle Grow, this can work very well producing big plants at the expense of the root system and the soil biology as a whole.
With a little work you can have great soil that will produce for you without having to go totally organic if you choose.
Your geographical location will give a picture of what your soil is like, clay, loam, sandy loam and so on.
If you are like most gardeners, you will have added some compost to the soil over the years, this will have changed the soil structure, if you till or have had the garden sub soiled, this will have changed it dramatically as well.
The only way to find out exactly what your soil composition is, and what you need to balance your nutrients is to send a sample in to be tested/analyzed.
Spring is just around the corner, a simple $30.00 test can lead to the best gardening season that you've ever had, once your soil is balanced, you will need much less fertilizers.
Most of us fall into the habit of thinking that we are fertilizing plants. Except for foliar fertilizer, we do not fertilize plants… we fertilize soil. Because of this, soil chemistry will determine how much of the applied nutrients the plants will be able to take up.
After reading hundreds of soil test report results and countless tissue test results, we have a clear picture of which nutrients are used up the fastest, during key growth phases and how certain plants react/respond to calculated applications of these nutrients.
I won't go into the more complicated topics such as how an unbalanced nutrients can lead to nutrients being locked up and effecting the nutrient uptake, each nutrient is dependent upon other nutrients which can have a major impact on everything from yields to plant health, disease resistance, pest resistance and more.
Ok, if you are still awake after that and still have some interest, let me know, it is difficult to try to put all of this info into a sequential order that will make sense without it becoming overwhelming.
This is part of what I did to help competitive growers become successful, but we also helped Greens keepers (golf courses), nurseries, landscapers, and small farms get the most out of their applications, their lively hood depended on it.
