pure

local seedsReady = false

local function checkForSeeds()
  local itemsFound = 0
  for i = 1, 12 do
    itemsFound = itemsFound + turtle.getItemCount(i)
  end
  if itemsFound > 0 then

        seedsReady = true
  else
    seedsReady = false
  end
end

local function checkSeedStatus()

  turtle.suckDown()
  for i = 1, 12 do
    turtle.select(i)
    for j = 13, 16 do
      if turtle.compareTo(j) then turtle.dropUp() end
    end
  end
end


while true do

  checkForSeeds()
  if seedsReady then

    redstone.setOutput("front", true)
    for i = 1, 12 do

      turtle.select(i)
      turtle.dropDown()
    end

    os.sleep(15)
    checkSeedStatus()
  else
    redstone.setOutput("front", false)
    os.sleep(6)
    checkSeedStatus()
  end
end