What Happens When a Plant Gets too Much Nitrogen? (2024)

FAQs

What happens if I give my plants too much nitrogen? ›

When plants receive too much nitrogen (N), they become more attractive to insects and diseases. It can also cause excessive growth and reduce the strength of the stems.

Too much nitrogen is especially harmful in the flowering stage, because this will cause your plant to produce much smaller buds. If you react quickly and reduce your nitrogen levels at the first sign of toxicity, your plant will quickly recover.

What Does Fertilizer Burn Look Like? The primary symptoms of fertilizer burns on plants are yellow or brown spots on their foliage. Foliage fertilizer burn can also show up as burnt, crunchy leaves. Lawn fertilizer burn shows up as streaks of discoloration on grass blades and dry brown patches of dead lawn grass.

Flush your soil daily until you notice your plants growing in a healthy fashion. This process should take roughly five days. However, it may take more or less time, depending on how nitrogen-rich your soil was and how long you left the problem before taking action.

You can lay mulch over the soil with too much nitrogen to help draw out some of the excess nitrogen in the soil. In particular, cheap, dyed mulch works well for this. Cheap, dyed mulch is generally made from scrap soft woods and these will use higher amounts of nitrogen in the soil as they break down.

Treating Your Plants

Are we talking about indoor houseplants? Then, the main way to fix fertilizer burn is to flush the soil out with water. Add enough water to flow through the potting mix and let it wash right out (not just collect in the pot tray). You may even need to repot the plants in fresh soil.

Add mulch to your soil, and stop fertilizing if you want to reduce the amount of nitrogen in your soil. Mulch uses up nitrogen as it breaks down, so applying a layer of dried wood or sawdust in high-nitrogen parts of your garden can suck up nitrogen. Nitrogen also leaches out of soil naturally.

Signs of Nitrogen Toxicity

Extremely dark green leaves. “Burning” of leaf tips, causing them to turn brown. Some leaves turning yellow, due to abundance of nitrogen but lack of other nutrients.

The best way to solve the problem of over-fertilization is to leach excess nutrients from the soil by using watering to slowly flush out the pot. (Your pot will need drainage holes for this.) To leach the soil, put your plant in a sink, tub, or outside where it can drain and give it a nice, long watering.

Soil nitrogen level is mostly determined by doing a soil test analysis. In addition to this, a grower can observe for deficiency symptoms in plants or do a plant analysis to know if his soil is nitrogen deficient.

How do you reduce nitrogen in potted plants? ›

High nitrogen levels in your potted plants may be lessened by frequent watering or flushing, adding organic materials or mulch, and applying compost.

Signs of nutrient burn on leaves

Leaf tips are bending or curling. Leaf tips turn yellow or brown—the plant is trying to get rid of excess nutrients and sends them to its furthest reaches. Leaves turn an extreme or oversaturated deep green colour—this indicates over fertilisation.

Responsive to extra nitrogen are: tomatoes, peppers, greens, sweet corn, pole beans, muskmelons, cucumbers, squash and okra.

Symptoms of excess nitrogen include thickened and sometimes cupped leaves with atypically deep green color. Overfertilization can cause leaves to turn brown, gray, dark green, or yellow at margins and tips or overall. Affected foliage may wilt temporarily or die and drop prematurely.

If your plant has been overfed, do not provide it more fertilizer until it appears healthy again (3 to 4 weeks). Allow time for your plant and its roots to recover from the strain of an overabundance of fertilizer. Choose a fertilizer without nitrogen.

Fertilizer burn is an appropriately named term—grass and plants look as if they have been scorched by fire when afflicted with fertilizer burn. Rather than a healthy green color, these plants will have brown or yellow streaks or splotches on them.

While nitrogen is deposited into the soil by a number of different pathways including nitrogen fertilizer, nitrogen fixation by leguminous crops, manure additions, and crop residues, there are fewer ways that nitrogen can be lost from the soil, like leaching, denitrification and volatilization.

First, I limit nitrogen-based fertilizer and use mulch or organic compost instead. Growing nitrogen-fixing plants can also help, as well as soaking the soil with water, hydrating lime, adding organic materials, or not doing and adding anything.

How long does it take for nitrogen to leave soil? ›

Again, it just depends on whether or not you use a wet or dry fertilizer. Liquid fertilizers that replenish nitrogen can last anywhere from two to six weeks. Granular fertilizers tend to be slow-release and can last anywhere from two to five months.

An excess of nitrogen, caused by fertilizer over-application, can result in rapid, lush growth and a diminished root system. In extreme cases, too much quick-release nitrogen can cause burning of the leaf tissue and plant death. 1 A lawn with a nitrogen deficiency will lose its green color and begin to turn yellow.

Using Plants That Will Reduce Nitrogen in Garden Soil

Any plant will use some nitrogen in the soil, but plants like squash, cabbage, broccoli and corn use up large amounts of nitrogen while growing. By growing these plants where there is too much nitrogen in soil, the plants will use up the excess nitrogen.

Nutrient burn can't be reversed, and any leaves or buds that have already yellowed or browned are never going to be green again. Snipping off any damaged leaves and buds will prevent parts of the plant that have already been injured or died from rotting and causing further headaches.

First, I limit nitrogen-based fertilizer and use mulch or organic compost instead. Growing nitrogen-fixing plants can also help, as well as soaking the soil with water, hydrating lime, adding organic materials, or not doing and adding anything.

Adding coffee grounds directly to the soil as a fertiliser can be a good option. Coffee grounds are rich in nutrients, especially nitrogen. They also have some amount of other nutrients like potassium and phosphorous. Overall, this means that adding coffee grounds to your garden can work fairly well as a fertiliser.

Nitrogen is a key element in plant growth, and plants need plenty of it in the growing season. But too much nitrogen can actually slow plant growth because nitrogen not used by plants is washed (leached) out of the soil, which makes soil acid.