HOW MANY PLANTS DO I NEED TO FILL THIS AREA?  
  
That is a loaded question with no right or wrong answer, but a lot of possibilities. In reality is all comes down to time and patience versus budget. Filling a bed packed tight can become more costly depending on the size. Some Flowers enjoy being packed tightly, while others need some room to allow them to form the best base possible then fill in from there.  We have most of that information filled in plant by plant on the spring and summer annual page.  
   
For a general guide line, you can use the chart to get fairly close.  As a frame for reference, when you see the commercial guys planting streets and entrances that look full and perfect, they generally use a 6-8” spacing guideline, which is anywhere from 2.5 to 3 plants per square foot of bed.  Yea, the math and square foot part really throws a curve into the basic addition.
 
If you have a rally large area to plant another trick is to plant a few plants close together and make several groupings, this can have more of an impact than spacing all the plants extremely far apart.

NUMBER OF PLANTS REQUIRED
Spacing Between Plants

10 sq ft.
2' X 5'

25 sq. ft.
5' X 5'
50 sq. ft.
5' X 10'
100 sq. ft.
5' X 20'
6"
40
100
200
400
8"
23
57
113
225
10"
15
36
72
144
12"
10
25
50
100
14"
8
19
37
74
16"
6
14
28
56
18"
5
12
23
45
24"
3
7
13
25