Need help maximizing my profit

I'll try my best to explain what I need to do, but even explaining it is somewhat complicated.

What I want to do is maximize my profit. There are 11 targets.

1. Begonia
2. Petunia
3. Rose
4. Magnolia
5. Daffodil
6. Rose
7. Zinnia
8. Crysanthia
9. Snowdrop
10. Lilac
11. Jasmine

They all have different starting numbers, different target numbers, and different revenues for when I get to the target number. For example, Begonia starts at 116 and I want to get her to 195. Once I reach 195, I will receive $180.

There are 8 items that increase the target's numbers:

1. Tea
2. Frosting
3. Popcorn
4. Butter
5. Licorice
6. Salad
7. Creme
8. Chocolate

Each time I add one of these items it costs a certain amount. For example: Tea costs $67.26, and increases Begonia's # by 10, Petunia's # by 10, Rose's # by 5, and Magnolia's # by 9.

Looking at the spreadsheet I already have might make it a little more clear. My objective is to create a program that tells me the cheapest way to make the most revenue (in other words, maximizes my profit).

Is what I'm trying to do not possible, or just really difficult?

Anyone have any thoughts?