Showing Nested Model Partials on user Index/profile page - ruby-on-rails-3

Question

I an struggling with the syntax of the controller for nested models. There are many other questions out there but i am not having any luck and i have reached my 2 day struggling threshold, so its time to ask!
I have 3 Models, User, Farm, Product. - User has_many Farms, Farm has_many Products.
On the user show page i display a list of farm/s created by the user in a partial...
#users_controller
def show
#user = User.find(params[:id])
#farms = #user.farms
end
#show.html.erb
<% if #user.farms.any? %>
<center><h4>My Farms(<%= #user.farms.count %>)</h4></center>
<hr>
<%= render #farms %>
This works as expected.
What i would like to do is display all the products of the farm, within the _farm partial, as a list. However I dont know what to add to the controller? Adding
#products = Product.find(params[:id])
obviously displays all products, not just one made by that farm. So how to i create the controller code and/or the partial code to only show the products created by that particular farm?
I was thinking along the lines of...
#products = Product.find(params[:farm_id])
but it does not work and seems to simple!
I obviously need to pass a key somewhere to the partial within the partial, but i have no idea how to do it!
Any Help will be massively appreciated...its driving me nuts!
Many thanks, Alex
EDIT ::
#product.rb
class Product < ActiveRecord::Base
attr_accessible :description, :farm_id, :name, :ammount, :price, :category, :pic, :longitude,
:latitude, :image
belongs_to :farm
mount_uploader :image, ImageUploader
#farm.rb
class Farm < ActiveRecord::Base
attr_accessible :content, :name, :user_id, :description, :street_name, :bldg_name, :region, :post_code,
:province, :contact_number, :swap, :organic, :deliver, :image, :products_attributes
belongs_to :user
has_many :products
acts_as_followable
validates :user_id, presence: true
accepts_nested_attributes_for :products
mount_uploader :image, ImageUploader
#user.rb
class User < ActiveRecord::Base
mount_uploader :avatar, ImageUploader
# Include default devise modules. Others available are:
# :token_authenticatable, :confirmable,
# :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :confirmable
# Setup accessible (or protected) attributes for your model
attr_accessible :email, :password, :password_confirmation, :remember_me, :name, :region,
:description, :avatar, :street_name, :bldg_name, :post_code, :province, :contact_number, :avatar,
:avatar_cache, :remove_avatar, :products_attributes, :product
# attr_accessible :title, :body
acts_as_follower
has_many :farms
has_many :swaps
has_many :products, :through => :farms
# validates_presence_of :image
# validates_integrity_of :image
# validates_processing_of :image
has_private_messages
EDIT 2 ::
#_products.html.erb
<hr>
<div class="row-fluid">
<div class="span3"> <%= image_tag product.image_url(:thumb) %> </div>
<div class="span5">
<h2><%= product.name %></h2>
<table>
<tr>
<td><strong>Ammount Available ::</strong></td>
<td><center><%= product.ammount %></center></td>
<td><strong>Kilos</strong></td>
</tr>
<tr>
<td><strong>Price/Kilo ::</strong></td>
<td><center><%= product.price %></center></td>
<td><strong>Euros</strong></td>
</tr></table>
</div>
<br><br><br>
<div class="span3">
<%= link_to "View Product", product, class: "btn btn-small btn-secondary" %>
<% if correct_user?(#user) %>
<%= link_to "delete", product, class: "btn btn-small btn-secondary", method: :delete, confirm: "You sure?" %><% end %>
</div>
-
#_farm.html.erb
<div class="<%= cycle("even", "odd") %>">
<div class="container">
<div class="row-fluid">
<div class="span2">
<%= image_tag farm.image_url %>
</div>
<div class="span2">
<%= farm.name %>
</div>
<div class="span4">
<span><%= " Location :: " %><%= farm.user.region %></span><br>
<span><%= " Can it be delivered :: " %><%= farm.deliver ? 'No' : 'Yes' %></span><br>
<span><%= " Is it Organic :: " %><%= farm.organic ? 'Yes' : 'No' %></span><br>
<span class="timestamp">Listed on <%= farm.created_at.strftime("%d %b. %Y") %> </span>
</div>
<div class="span4">
<br>
<br>
<br>
<%= link_to 'Sell A Product', new_farm_product_path(farm), class: "btn btn-small btn-secondary" %>
<%= link_to 'Edit Grow Spot', farm, class: "btn btn-small btn-secondary" %>
</div>
</div><!-- end container -->
</div>
<div class="row-fluid">
<div class="span2"></div>
<div class="span8">
<% for product in farm.products do %>
<%= render :partial => "product", :product => product %>
<% end %>
</div>
<div class="span2"></div>

Answer 1

Using <%= render #farms %> in a view means you must have a partial called _farm.html.erb in app/views/farms
in that partial you can use farm variable:
<% for product in farm.products do %>
<%= product.name %>
<%= product.price %>
....
<% end %>
no need to add something in controller.
update
<% for product in farm.products do %>
<%= render :partial => "product", :locals => { :product => product } %>
<% end %>
in app/views/farms/_product.html.erb
<div class="zzz">
<div><%= product.price %></div>
</div>