yeah spending 15k on the garden sounds ridiculously high to me, even with paying laborers, if that is included. i'm pretty extreme on the other end of not spending money, and am not a market gardener, though we produce a surplus on many things, and our gardens have more eaters than gardeners. but still i cant even imagine spending that much money, like how it could add up that high...i think even with every fancy thing one could get each year...i couldnt even manage to spend that say if i actively tried. of
course if labor is included, i suppose thats quite different. for much less than that, one could put up a
greenhouse, to help with starting seeds.
i also get a lot of seeds for free ish by trading, cost of the stamps and the seeds i save myself, start most everything from seed-- even
trees, that does take considerably longer to get to a harvest age, but its all extremely cheap. last year i splurged on a number of cool perennials, and actually purchased a lot of seeds, mostly uncommon
perennial seeds...and maybe spent a couple of hundred dollars total. i am working through it these days, and now have so much seed its going to be hard to find time and space to plant them all. and my landmates went and purchased a number of named trees and perennials...still probably not adding up to more than a few hundred dollars total, getting some very high value fruit trees, blueberries and other berries and currants. even just a couple of hundred dollars in starts is quite a lot of plants,
enough to supplement whatever seed starting can be done.
from my own little business ventures, i have learned that one of the main keys to making it work is not to have to make more and more and sales, as seems obvious. although of course this helps! but the real key is making sure you are not spending a lot of money to make those sales.
theres so many little things that come up, to buy office stuff at a staples type place, to buy new hoses say, instead having to patch up old water lines, etc etc...theres all this little stuff...that many people just go out and get, this ends up adding up to a lot more than it seems while you are there buying those odds and ends. so eliminating as much of those kinds of things as possible, trying to only do that when you are totally sure it is completely needed, and keeping your costs and overhead as low as possible, this is the key to a small business, IMO.