Crop Farmer

local farmSideLength = 5
local inspectAttempts = 5
local desiredFuelPercent = 0.5

local function forward()
    while not turtle.forward() do
        turtle.dig()
    end
end

local function checkDown(name)
    local i
    for i = 1, inspectAttempts do
        local success, blockData = turtle.inspectDown()
        if success then
            return blockData.name:find(name) ~= nil
        end
    end
end

while true do
    turtle.select(1)

    forward()
    forward()
    turtle.turnRight()
    turtle.placeDown()

    local i, j
    for i = 1, farmSideLength do
        for j = 2, farmSideLength do
            forward()
            turtle.placeDown()
        end
        if i < farmSideLength then
            if i % 2 == 1 then
                turtle.turnLeft()
                forward()
                turtle.placeDown()
                turtle.turnLeft()
            else
                turtle.turnRight()
                forward()
                turtle.placeDown()
                turtle.turnRight()
            end
        end
    end

    for i = 1, 2 do
        turtle.turnRight()
        for j = 2, farmSideLength do
            forward()
        end
    end

    forward()
    forward()
    if
        turtle.getFuelLevel() ~= 'unlimited' and checkDown('pedestal') and
            turtle.getFuelLevel() < turtle.getFuelLimit() * desiredFuelPercent
     then
        turtle.select(16)
        turtle.suckDown()
        turtle.refuel()
    end
    sleep(60)
end