Have you ever wondered why hazelnuts and daffodils, as well as other forageables, stay away from your farm unless you specifically plant them? This mod changes their behavior. Now they are as likely to spawn on your farm, as in every other part of Stardew Valley, and even more likely if you just wish so (and make some tweaks in the config file).

What the mod does
At the start of every day the mod runs a check to see if there are any suitable and empty tile, and spawns a number of forageable items. By default the mod checks the whole farm and spawns 1 seasonal item (on average) on the grassy tile, but these can be changed. Items lists for every season are also up to change (items are defined by the ID and an incomplete list of ID's is included in the readme file). Additionally, your foraging skill and daily luck may raise the number of spawned items (or drop it if you are very unlucky).

Also, if you want more functionality (source of hardwood) of the forest farm for other farms check my other mod Stumps to Hardwood Stumps.
And if you want features of Hill-Top farm, check Mining at the Farm mod.

Note: the forageables on the farm are not restricted in number like in other locations and are not removed every week, which makes theoretically possible to fill the whole farm with spawned items. They still are removed at the end of the season though.

Installation
1. Install the latest version of SMAPI
2. Unpack the downloaded zip file and place it's contents into the Mods folder
3. Load a character to create a config file for that character.
4. Close the game and tweak configs to your liking. If you want to reset all settings to default, delete existing config file and the next time you load the game a new config will be created.
5. Play the game.

Configuring settings
1. spring-/summer-/fallForage - lists of ID's for items to spawn. Default values are set to seasonal forage. More ID's can be found in the unpacked ObjectInformation.xnb. Do not change these unless you know what you're doing.
2. Set coordinates for the upper-left and bottom-right corners of the area (or several areas) where forageables can spawn. There 3 ways to see what are the coordinates for your desired area:
2.1 Using tIDE. The obvious downside to this method - you need to read how to unpack/repack map files and how to use tIDE - so, unless you already have experience making custom maps, this method is not recommended.
2.2 Using Stardew Valley planner. Upload your save file, toggle coordinates in options and they will be shown at your cursor position. Downside: Stardew Valley planner doesn't work with custom maps (it will show one of the standard layouts), so if you're using custom map this method isn't really good.
2.3 Using debug mode. Requires this mod to turn on debug mode.
3. Set soil type for tiles where forageables can spawn. There isn't uniform best answer for all the maps, but generally using "Diggable" will cover the largest number tiles, though on the forest map "Grass" is also a viable option.
4. Set the average number of items per day with baseNum. Note that this number is further modified by foraging level and daily luck.
5. For more detailed descriptions of config options read readme file. Seriously, read it.