When should I fertilize my flower garden?

I just ordered some flowers online and I was wondering if it would be better to put fertilizer in the soil before the flowers arrive, or if I should wait to put it in ground when I plant the flowers. Also if you could suggest a good fertilizer that would be great. I live in Tennessee if that matters.

When should I fertilize my flower garden?
Fertilizing


Most perennials are not heavy feeders. A light fertilization of 2 to 3 pounds of 5-10-10 or 10-10-10 per 100 square feet should be applied in early spring. A second application is often made in mid-summer at the rate of 1 1/2 to 2 pounds per 100 square feet. Take into consideration the amount of plant growth -- if growth is adequate you may not need to fertilize. Too much fertilizer will promote foliage and possibly diseases without necessarily promoting flower production. It is not necessary to remove the mulch before fertilizing. Water after applying fertilizer; this will wash fertilizer off the foliage, prevent foliage burn, and will make the fertilizer available more quickly.





Deadheading


After perennials have bloomed, spent flowers and seed pods should be removed. Keep in mind that some perennials do not require deadheading since the seed pods are either not very visible or are quite attractive. Cut the flower stem down to a healthy leaf or side branch. This will keep the plants looking neater and will prevent them from wasting energy by producing seeds. Some plants produce so many seeds and volunteer plants that they become overcrowded and invasive. Deadheading will reduce the problem. Some perennials will rebloom if cut back after the first flush of flowers.





Pinching


Some plants will grow thicker and fuller if the terminal growth is pinched. This reduces the height and reduces the likelihood that the plant will be blown over by wind and rain or from the weight of large, heavy flowers. The result is a more compact plant with more but sometimes smaller flowers. Pinching often delays flowering. Plants that respond to pinching include chrysanthemums, asters, and phlox. Start pinching in early spring when the shoots are several inches long and discontinue by early July.
Reply:fertilize when you put them in the ground..I use a fertilizer called Peters 20 20 20. You can use it everyday and it wont hurt your plants it's good for all kinds of plants
Reply:I recommend putting some fertilized garden soil around the plants when you put them in. It will allow the plants to root better and it will already have the slow release fertilizer in it. Miracle Grow makes a good garden soil.





Or just add a little fertilizer to the bottom of the hole you dug when you put the flower in. That makes the fertilizer right there ready for the roots to use.





If you have perennials, don't fertilize much in the summer. Mainly fertilize in the spring and fall. Fertilizing too much in the summer will burn the plants and cause the plant to dry out due to the chemicals/salts.





Another great thing you can do is add some rabbit manure to the bottom of the hole you dug. That will give the plant nitrogen and micro minerals that it needs. The organic matter will also help hold water for the plant to use during heat spells and will be soft to easily get roots through. My great and does that and swears her flowers are twice as big. I use it to get my tomato plants 2-3 times as big.
Reply:It depends on how big you want your flowers to get! All purpose fertilizers like Peters or Miracle-Gro can be applied regularly -- I use Miracle-Gro every two weeks with good results.