Although nitrogen is one of the most important plant nutrients, an excess of nitrogen in the soil can damage plants instead of nourishing them. Fruit and vegetable plants that are getting too much nitrogen produce a lot of lush green foliage but not a lot of fruits or vegetables. One way to reduce the amount of nitrogen in the soil is to grow a nitrogen-needy crop such as corn. However, if the garden is in a poor location or too small for a corn crop, leaching or mulching may be the better methods.
Things You'll Need
- Low-nitrogen mulch
Clear away large debris and plants from the area being treated. Established plants can stay but may be affected by the excessive amount of water used in the leaching process. Temporarily transplant water-sensitive plants to containers, if possible.
Saturate the soil with water. The area must be soaked with water to several inches below the surface in order to leach out the soluble nitrogen.
Maintain this level of saturation for at least three days.
Take a soil sample to your local cooperative extension office for testing. Repeat the leaching process if the nitrogen level is still too high.
Purchase a low-nitrogen mulch such as wood chip mulch or sawdust.
Spread mulch over the affected area to draw out the excess nitrogen. Cover the soil completely, but a deep covering is not necessary.
Take a soil sample to the local cooperative extension office for testing at the end of the season. Add more mulch if the nitrogen level is still too high.
Tips & Warnings
- Leaching dissolves excess nitrogen in water and carries it either deeper into the soil away from plant roots or washes it away completely.
- Only use the leaching method on small garden beds to avoid wasting water.
- Cornell Cooperative Extension of Suffolk County; The Types and Uses of Mulch in the Landscape; Donald A. Rakow; July 1989
- University of Minnesota Extension; Understanding Nitrogen in Soils; Mike O'Leary, et al.; 1994
- USDA Agricultural Research Service; Lowering Nitrogen Rates To Increase Profit, Environmental Sustainability; Ardell D. Halvorson; February 2009
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