This calculator helps you determine the amount of fertilizer needed to achieve a specific nitrogen application rate for your lawn. Proper nitrogen application is crucial for healthy turf growth, providing the necessary nutrients for vibrant green color and robust root development. Over-fertilizing can lead to lawn burn and environmental runoff, while under-fertilizing can result in a weak and discolored lawn.
function calculateFertilizer() {
var lawnArea = parseFloat(document.getElementById("lawnArea").value);
var nitrogenRate = parseFloat(document.getElementById("nitrogenRate").value);
var fertilizerAnalysisN = parseFloat(document.getElementById("fertilizerAnalysisN").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = "; // Clear previous results
if (isNaN(lawnArea) || isNaN(nitrogenRate) || isNaN(fertilizerAnalysisN)) {
resultDiv.innerHTML = 'Please enter valid numbers for all fields.';
return;
}
if (lawnArea <= 0 || nitrogenRate <= 0 || fertilizerAnalysisN <= 0) {
resultDiv.innerHTML = 'All values must be positive.';
return;
}
// Calculate total nitrogen needed (in lbs)
var totalNitrogenNeeded = (lawnArea / 1000) * nitrogenRate;
// Calculate amount of fertilizer needed (in lbs)
// Formula: (Total Nitrogen Needed / Fertilizer Analysis N %) * 100
var fertilizerAmount = (totalNitrogenNeeded / fertilizerAnalysisN) * 100;
resultDiv.innerHTML = 'To achieve a nitrogen rate of ' + nitrogenRate + ' lbs per 1000 sq ft on your ' + lawnArea + ' sq ft lawn, you will need approximately ' + fertilizerAmount.toFixed(2) + ' lbs of fertilizer with an N value of ' + fertilizerAnalysisN + '%.';
}
.calculator-container {
font-family: sans-serif;
max-width: 600px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
background-color: #f9f9f9;
}
.calculator-container h2 {
text-align: center;
color: #333;
margin-bottom: 20px;
}
.calculator-container p {
line-height: 1.6;
color: #555;
margin-bottom: 20px;
}
.inputs {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 15px;
margin-bottom: 20px;
}
.form-group {
display: flex;
flex-direction: column;
}
.form-group label {
margin-bottom: 5px;
font-weight: bold;
color: #444;
}
.form-group input[type="number"] {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
}
.calculator-container button {
display: block;
width: 100%;
padding: 12px 20px;
background-color: #4CAF50;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 18px;
transition: background-color 0.3s ease;
}
.calculator-container button:hover {
background-color: #45a049;
}
.results {
margin-top: 20px;
padding: 15px;
border: 1px solid #d4edda;
background-color: #d4edda;
color: #155724;
border-radius: 4px;
text-align: center;
}