You may have noticed the letter NPK on bags of fertilizer or other organic matter in the past. These letters stand for Nitrogen-Phosphorus-Potassium (in that order) and these are essential nutrients for your garden and its plants.
Of these three nutrients, nitrogen is often the one that is most difficult to get to the right level. It can be very transient but is critical for plant growth.
Signs of low levels of nitrogen include:
- yellow or pale green leaves
- slow plant growth, despite other good conditions
Some plants use more nitrogen than others. These include:
To replenish the nitrogen in your soil, you may have to do more than just add compost, especially if you often grow many of the crops listed above.
Here are a few ideas for boosting your nitrogen levels:
Cover crops of alfalfa, clover or peas can help boost the nitrogen levels in your soil. These crops will be turned into the soil after you are finished with them (as opposed to being pulled up and composted, as you may do with other crops).
- Composted manure, especially poultry manure
- Blood Meal
- Fish emulsion
- Chilean nitrate – a soluble mineral salt mined in Chile
I’m planning to plant a cover crop this fall in the front yard to help build up the soil. I’m thinking of planting fava beans, as they grow very well here and my mom claims that they are delicious. What do you do to increase the nitrogen in your soil where you are?
I got a lot of the information from this article from the wonderful magazine Organic Gardening and a recent article written by Beth Hanson in Vol 60:2 titled Nitrogen: The Elusive Nutrient. I highly recommend this magazine if you don’t already subscribe.