So as a demo farmer in primary:

1. When is the best time to start stocking?
2. How much land should I aim for to end top 25ish?
3. What is the best way to stock as farmer? Should I buy food on market with my money and sell higher by a few dollars each day or just cash turns and sell food on market at a rly high price to avoid decay?

1. Week 5 onwards is a good time, but you can still do daily PSes.

2. 40k-50k.

3. The former if you're Demo, the latter if you're not Demo.

Figure out the cost it takes for you to grow each day and compare it to how much you can make back on the land gained.

For example, if you on average grab about 1.5k aces per day, it's not worth it to grab more land if there is only 15 days left and you are already 50k acres. However, it is worth it to grab lab if you are 50k acres and there are 30 days still left till the end of the set.

And yes as Demo, you should always be on the lookout to make some easy money by buying under priced items and reselling them for a higher price to make money.

As to how often you sell your bushel depends on your decay rate and how much money you are making cashing. If you will be losing more $ than you can from cashing, then sell the bushels. Again, I can't tell you exactly since this depends on your level of business/res tech and current bushel prices.

farmers don't stock, they just eat and sell. Then they take that money and buy land.