Just a simple guide on how to grow crops as i haven't found anything on it and figured out some of it.
Build a Planter Box
Just build a Planter Box.
Can be placed inside of your base. But, if there is any kind of roofing with no sun light they grow slower. (Haven't tested if building walls with no roof makes a difference).
How to Add Dirt to the Plot Box
Now to add some dirt to the crop plot. you have to Craft a Large Bag. which is located in the crafting tab, Cloth>Bags. Cost's 2 Rags to make. only need 1 bag per plot. you can also re-use the bag.
Once you've made your bag. Just go too a grassy area. Then open your inventory. Right-Click on the Large bag, then it should say Fill With Dirt. Then go back to your Plot, mouse wheel up/down while looking at the Plot and add the dirt.
Adding Water to Your Plot
Now to fill the plot up with water. Anything that holds water will work for this. First time i used 4 Plastic Military Cantene's to fill it. Second time took 2 jerry can's. I also refilled them at the river(unsure if this makes a difference of where you fill them.)
Again, go to your crop plot with what ever container filled with water, mouse wheel on the plot and add water til it say's it doesn't need any more.
Fertilizing Your Crop Plot
Now to Fertilize your crop, ANY rotten vegitables will do the trick. Seems to be either 3 or 4 rotten items is full. Again with these items in your inventory. Mouse wheel on the plot and use the rotten items.
Finally Adding Seeds to Your Crop Plot
Once you have some seeds in your inventory. Mouse wheel at your plot and it'll show which seeds you wish to plant(only shows what's in your inventory).
That's it! Now your farming! Note that it seems to take about 45-60minutes for them to fully grow. The first one i timed at 1 hour and 15 minutes but that was with only one rotten item and inside a closed base. Tried timing the second go out side but became busy while timing.
But, once it's done growing you'll get a crop plot lookingg like this.
Then you can go to it and it'll say "Harvest Crop". That's it.
Unsure of the numbers of what you get but i did beats the first time i think and got 6 or 9. Second was pumpkin and got 5. The picture above was radishes and got 12. Don't know if letting them stay longer does anything for amount yet. also i'm sure how well you setup the crop plot to grow may make a differece. (Unless purely for time.)
I'm unsure if other players can interact with the plot, but if they don't take it, they may be able to destory it in the mouse wheel options.
Also, if you pack the plot up, you'll have to do everything all over again.