The exact amount of urea you should use depends on the specific nitrogen (N) needs of your plants or soil, which are typically categorized as low, medium, or high. For effective nitrogen fertilization in gardens, consult the application rates provided by experts like the WVU Extension, which detail the recommended ounces of urea per 100 square feet per year based on these needs.
Understanding Your Nitrogen Needs
Before applying urea, it's crucial to understand your garden's nitrogen requirements. This is often determined by:
- Soil Testing: The most accurate way to assess your soil's existing nutrient levels and determine if nitrogen is a limiting factor.
- Plant Type: Different plants have varying nitrogen demands. For instance, leafy greens generally require more nitrogen than fruiting plants.
- Previous Fertilization History: If you've recently added organic matter or other nitrogen sources, your current needs might be lower.
Once you have an understanding of your garden's N Class (low, medium, or high nitrogen need), you can refer to the table below for precise application rates.
Recommended Urea Application Rates
According to the WVU Extension, here are the recommended amounts of urea to use for various nitrogen needs:
| Relative N Need | N Class (Pounds N per Acre per Year) | Ounces Urea per 100 Square Feet per Year |
|---|---|---|
| Low | 75 | 6 |
| Medium | 100 | 8 |
| Medium | 125 | 10 |
| High | 175 | 14 |
How to Use This Table
- Identify Your N Need: Based on your garden's requirements (e.g., determined by a soil test or general plant vigor), classify it as Low, Medium, or High N need.
- Select the Corresponding Rate: Find the row that matches your N need and read across to the "Ounces Urea per 100 Square Feet per Year" column.
- Measure Accurately: Use a kitchen scale or a measuring cup (knowing the approximate weight of urea per cup) to ensure you apply the correct amount.
Important Considerations
When applying urea, which is a highly concentrated nitrogen fertilizer (typically 46-0-0), keep the following in mind:
- Application Method: Urea should be spread evenly over the soil surface.
- Watering In: Always water the area immediately after applying urea. This helps move the nitrogen into the soil and reduces the risk of nitrogen loss through volatilization (conversion to ammonia gas).
- Avoid Over-Application: Too much urea can burn plants, especially tender seedlings, due to its high salt index. Stick to the recommended rates.
- Split Applications: For higher nitrogen needs, it's often better to split the total yearly application into several smaller doses throughout the growing season rather than applying it all at once. This ensures a steady supply of nitrogen and minimizes loss.
By following these guidelines and utilizing the specific rates provided, you can effectively use urea to support healthy plant growth in your garden.
