Atomicrops

Year:

1 or 2 (Playing on year 3 or higher will cause weed monsters to start appearing on the farm and might make going for this achievement more difficult.)

Helpful Upgrades if Found:

• Squaredown (This upgrade will cause weeds to grow faster)
• Succulent Weeds (This upgrade will cause weeds to have a higher drop rate.)

Sunflowers:

This achievement is pretty straightforward. For me the fastest way that I have been able to get Sunflower Seeds is from using the Wacker Tractor. Every now and then I'll get sunflower seeds from beeson or enemies, but I personally feel like getting sunflower seeds from weeds is faster.

Once you have all 12 seeds, you can plant all 12 individually or make 3 big sunflowers. I personally would make 3 big sunflowers because you use less fertilizer, it is easier to get all 3 sunflowers fully fertilized at once than to try and do all 12, and you get more money. If you do each sunflower individually, you'll need 600 fertilizer, or if you do the 3 big sunflowers, you'll need 150 fertilizer.

Plant all 3 big sunflowers first, and the fertilizer them all the way. You have a larger time frame before the sunflowers die planting them all first and then fertilizing them. Trying to plant sunflower 1 and fully fertilize it and then planting sunflower 2 and fully fertilize it, the planting sunflower 3 and fully fertilize it will give a very tight time frame.

Edit: I got this achievement shortly before the Doom and Bloom update came to console.