Can anyone help me
I trying to do a piece of coding which has two groups of radio button in them one that selects the water system and the time it take and the other one selects which soil type and how many time to water the soil for. I al so have a checked box if there are large plants to be watered which added and extra 1.5 time on
I need to validate also if the radio button have been checked or not.
I am have problems working on the calculation being a newbie at all this JavaScript thing

<!doctype html>
<meta charset="utf-8">
<title>Home Gardening Watering guide</title>

//Check the users responses and calculate the fare
function fareCalc() {
var radioButton1; // A radio button
var radioButton2; // A radio button
var checkbox; // A checkbox
var watersystem = 0; //The number of the fare selected
var soilType = 0; //The number of the seat
var wateringTime = 0; //Total cost of the fare

//Find the valueof the waater system button
for (var i = 1; i <=4; i++) {
radioButton1 = document.getElementById("water" + i);
if (radioButton1.checked == false ) {
watersystem = radioButton1.value;
alert ("please select your watering system")

//Check if there are large plant involed
for (var i = 1; i <=1; i++) {
checkbox = document.getElementById("trees");
if (checkbox.checked == true) {
trees = "1.5";
if (checkbox.checked == false) {
trees = "0";
// Get the selected soil type
for (var i = 1; i <=3; i++) {
radioButton2 = document.getElementById("soil" + i);
if (radioButton2.checked == true) {
soilType = radioButton2.value;
// alert if no seating class selected
if (soilType == 0) {
alert ("Please select a seating class");

//Display total cost of selected fare
wateringTime = watersystem * trees * soilType ;
//Round to the nearest number
wateringTime = Math.round(wateringTime);
//Turn string into Integer
wateringTime = parseInt(wateringTime);

//Display total cost of flight
alert ("The cost of the flight is $ " + wateringTime);

<h1>Gotham Airlines Fare Calculator</h1>
<p>Complete the form below to calculate the cost of your flight.</p>
<input type="radio" id="water1" name="water" value="6"> <label for="water1">Jet Spray </label><br>
<input type="radio" id="water2" name="water" value="10"><label for="water2">Sprinkler </label><br>
<input type="radio" id="water3" name="water" value="17"><label for="water3">Mini Sprinkler</label><br>
<input type="radio" id="water4" name="water" value="50"><label for="water4">Dripper </label><br>

<p>Click here if you will be purchasing a return fare:<input type="checkbox" id="treeses" name="trees"><label for="trees" > </label><br></p>
<input type="radio" id="soil1" name="soil" value="2"><label for="seat1">Sand</label><br>
<input type="radio" id="soil2" name="soil" value="1.5"><label for="seat2">Loam</label><br>
<input type="radio" id="soil3" name="soil" value="1"><label for="seat3">Clay</label></p>
<p><input type="submit" value="Calculate" onClick="fareCalc();"> <input type="reset" ></p>