Ok, so, I'm running a little behind on some of the updates I've been preparing, but I've just added a beta version of the 'crops' seen in the above image. In the downloads section is a zip with a PSD and collection of PNGs. The png's are straight exports so they are the size of the asset.
I will probably create versions that all align at some point so they're easier to impliment, but for now, the raw assets are there if you don't mind some tweaking of positions. There are 6 assets for each crop; seed, 4 stages of growth and a seperate 'harvested' asset too.
I've removed the white outline so you have the option to add that in code if you want it. 

More updates coming soon. It's been a hectic month but keep peeled for more!