Nitrogen is a vital nutrient for plant growth, because it supports green, healthy leaves. Because house plants are grown in containers, where they have limited access to nutrients from the soil, fertilizing your house plants is key to successful indoor gardening. Knowing the signs of nitrogen deficiency and how to select the proper nitrogen fertilizer to correct the problem will help you foster healthy development among all your indoor plants. Regularly fertilizing your house plants with a nitrogen fertilizer will also prevent the problem from recurring.
Look for signs of nitrogen deficiency in your house plants. Plants that are lacking nitrogen will have light, yellowing leaves. Eventually the leaves may die. If your plants exhibit these symptoms, look for a nitrogen fertilizer at your local garden store or plant nursery.
Look for a fertilizer with a high nitrogen ratio. On the front of every fertilizer container are three numbers. Most indoor fertilizers have numbers close to 20-20-20, which means that the fertilizer contains 20 percent of nitrogen, phosphoric acid and potassium (or N, P and K in element symbols) respectively. If your plants are exhibiting severe symptoms of nitrogen deficiency, find an indoor fertilizer with the highest nitrogen number (the first number in the series). If your plants do not seem to be in crisis, a standard 20-20-20 fertilizer should be sufficient.
Apply the fertilizer to your plant according the manufacturer's instructions. Some granulated fertilizers should be mixed with water before they are applied to the plant, while other fertilizers are sold in liquid form and can be applied on their own. Do not apply more fertilizer than the manufacturer suggests; this can stun or kill your plant.
Reapply the fertilizer only as often as the instructions on the package suggest. Fertilizing regularly will help keep your plants healthy, but fertilizing too often will have the opposite effect. If your plant's leaves continue to die or look yellow a few days after you apply the fertilizer, there may be a different problem. Root-bound plants can exhibit symptoms similar to nitrogen deficiency, but these plants simply need to be repotted in a larger container. If your plant does not improve, do not apply more fertilizer. Overfertilization will only aggravate whatever problem your plant is having.