using blood meal, bone meal, compost/manuar blend, alfalfa, etc?
If you use too much you could get lots of growth at the expense of flowers. Normally, except for the manure and blood meal, you'll seldom be able to apply too much.
Keep in mind, a little, often, supplies a steady nutrient source and more even growth. A lot all at once of anything is not good.
If you're applying a lot because you don't want to fertilize so often, use slow release fertilizers like Osmocoat or other time release fertilizers.
Yes. I put 4 inches of compost that was still too hot on some roses last year and burned the bottom four inches of cane on all of them -- they died. So if you have new compost that's not completely cool, keep it away from the canes. And actually, I've seen alfalfa applied too close to the canes burn them also. Also, with bands or very young plants, new rootlets can be easily burned with too much fertilizer in the planting mix, even organics, so you need to go light on young newly rooted plants for that reason also. Plus, it could just be an expensive waste of materials to use too much.
Ok then the next question would be how much of each ingrediant per plant;
Depends on what your soil needs. Have you had a soil test done? If not, then it is difficult to tell how much each plant needs. It is the health (or lack of health) of the soil that dictates what and how much of any fertilizer that you might need.
Blood meal is a fast acting nitrogen source. Bone meal is slow (very slow) source of phosphate, and most useful when mixed in the soil near the roots when planting. Not useful when placed on top of the soil. Alfalfa is also fast nitrogen and also contains a growth stimulant, tricolnatol. It is also used as a soil amendment. Compost and composted manures are typically used as soil amendments, improving the organic component of the soil. They have a small amount of N and some P and K, but usually not enough as fertilizers on their own. Epsom salts add magnesium, and if your soil is already heavy with magnesium, the addition of Epsom salts will be detrimental to the health of your plants.
Here is a link that might be useful: NPK Composition of Materials
Yes, don't add Epsom salts (magnesium sulfate) unless a soil test calls for it. Most soil in the US has plenty. The others can be mixed in equal amounts except the manure/compost. It should be used separately in place of the others. I mix the blood, fish, alfalfa, and cotton seed meals plus Milorganite together in equal amounts and apply two cups at the dripline of each bush every 6 weeks throughout the summer. One half cup per miniature. If I use compost or a manure, I use it in place of the mix at the same rate. For a quick pick me up I'll broadcast 46-0-0 in the beds and water it in well or dissolve it in my fertilizer injector and apply it as I water.
Here's my suggestion. I garden in Sonoma and Marin counties. If you're in the valley, your soils are likely to be well-understood and won't need many amendments. Speak to a Master Gardener at the local Extension office to confirm the level of magnesium in local soils is low. Your soils may have adequate micro-nutrients. Almost all soils need some nitrogen.
I'd skip the bone meal. Bone meal isn't useful on the surface, except to varmints, who, like dogs, like to eat it. It should be added as an amendment at root height when you first plant.
1 cup of alfalfa meal, watered well to break it down quickly
1 cup of bloom meal, scratched in (varmints love it too)
top dress with several inches of compost out to the drip line.
I suspect that fertilizer companies are primarily in the business of selling fertilizer. Recommended dosages - applied correctly - are very unlikely to burn your plant roots but are probably at the upper end of what is actually needed. Applying a bit less will likely make very little difference to plant growth. Anyhow, if your plants are underfed, they will quickly tell you and you can correct the situation by applying a little bit more.
When a plant gets too much fertilizer, several things can happen...you will begin to notice things such as stunted growth, excessive growth of foliage with few blossoms, and yellowing or browning on the edges of leaves...
Blood meal contains fast nitrogen (urea and nitrate). Too much will definitely burn. Never exceed the labelled dose of anything.
Very similar question to "Is too much salt bad for you?" Apart from nutrient issues, most of the above come with it their dose of mineral salts. Overdoing the fertilising thing can result in a rapid build up of salts, which is bad for the roots. Those of use who grow orchids are acutely aware of this problem.
In my part of the world, I've never heard of the natural fertilizers causing a problem.
Rose exhibitors locally have found excess accumulations of K and P and other things (When soil testing labs ask why they sent fertilizer in for a soil test, they knew they had problems). This has led to total remediation of their gardens: dig the roses out, store them, dig out and remove the soil and replace the soil and replant the roses. Here it's generally taken eight to ten years to reach the excess K and P with steady applications of chemical fertilizers. Their rainfall is moderate and the zone is USDA 7.
Years ago we heard a fertilizer salesman talk about some of the things he offered: phosphate from Florida being one of them. Y'all may know that Florida had extensive phosphate mines at one time and the left over tailings are still Phosphate rich. This salesman packages up the tailings and labels the phosphate at a certain percent. OK, so you aren't worried. But then comes the kicker: the labeling requirements are for a guaranteed % Phosphate; there is NO concern that the phosphate could be ten times higher than the packaging says it is. So long as it meets the label minimum, it's legal.
Which is why soil tests are good when you aren't sure just how your garden is growing?
Well, I know if I used all that my dogs would eat everything in the garden.