Fertilizer burn is caused by the accumulation of mineral salts or plant macronutrients like nitrogen in the plant tissue, which dehydrate the plant and dry it out. The common symptoms of fertilizer burn include wilting and yellowing leaves, leaf and root scorch, and even plant death.
Here is how you can fix fertilizer burn on your tomato plants in ten easy steps:
- Scrape away excess fertilizer.
- Water the plant thoroughly with distilled water.
- Remove dead foliage from the plant.
- Add mulch to the soil.
- Prune away dead roots and flush the roots completely.
- Change out the potting soil and repot the plants.
- Ensure that the soil has good drainage.
- Keep the plant safe from sunburn and windburn.
- Resist the temptation to work on your plant.
- Restart feeding lightly after a few weeks.
In this article, I will explain exactly how you can go about rescuing your tomato plants if they’re suffering from fertilizer burn. As long as the plant still has some green on it, it can be saved, so read on!
1. Scrape Away Excess Fertilizer
Overfertilization is a common problem for most plants and gardens, especially for vegetables and ornamental plants. Plants can only uptake so much nutrition at a time. If you add more fertilizer than they can use, the salts in the fertilizers will begin to accumulate outside the plant.
The build-up of mineral salts in the soil leads to the formation of a salt crust on the soil’s surface. Excess fertilizer simply sits on the soil without being absorbed by the plants, drawing out moisture from the plant tissue and causing fertilizer burn.
If you see signs of fertilizer burn in your tomato plants, the first step is to scrape away the crust formed by the accumulated salts. All the excess fertilizer needs to be removed from the soil, so it doesn’t dehydrate your plants any further. This includes any fertilizer that may be sitting on the surface of your leaves from the foliar application.
A desiccated plant cannot uptake nutrients, so any fertilizer present in the soil will be essentially useless. Excess fertilizer will make things worse, so it must be removed immediately to allow your tomatoes the chance to recover from fertilizer burn.
Be careful not to damage the plants or remove too much soil when removing the excess fertilizer. Soil is essential when it comes to sustaining your plants with all micronutrients and water they need as they recover from leaf and root scorch.
2. Water the Plant Thoroughly With Distilled Water
Fertilizer burn is caused when the minerals salts in fertilizer accumulate and draw water out of the plant tissues. After removing the source of the problem, the second step to fixing fertilizer burn in your tomato plants is replacing the lost water.
Plants suffering from fertilizer burn are severely dehydrated. All plants uptake nutrients from the soil using water as a carrier, so when the concentration of fertilizers is too high, plants get desiccated. Watering your tomato plants thoroughly is the most important step to fixing the effects of fertilizer burn in these plants.
You can use regular tap water if that’s what’s available, but distilled water is preferred as it will not contain any additional minerals that could build up outside the plants.
Plants suffering from fertilizer burn are extremely fragile and can be damaged easily. Using distilled water instead of tap water allows plants to filter out excess salts from their tissue without having to deal with any other minerals that may be present in regular water.
As you water your tomato plants, the fertilizer will become diluted, and eventually, the water will flush it out of the soil and your plants.
Watering your plants also allows them to rehydrate themselves, restore the process of photosynthesis, and disperse the existing nutrients to the remaining leaves. These activities will help your tomato plants start growing again, fixing fertilizer burn.
3. Remove Dead Foliage From the Plant
The effects of fertilizer burn include wilting, yellowing, browning, and scorch marks on the leaves. The leaves will feel dry and crumbly, unlike the browning caused by overwatering, where the leaves tend to feel squishy like they’re rotting.
Leaves that have only begun to wilt might be rescued with sufficient watering to flush out the excess fertilizer and rehydrate the leaves. However, leaves that have begun to wilt, yellow, or brown have already started dying. Once the foliage has started yellowing, it cannot be fixed, as it has lost chlorophyll and will no longer be able to perform photosynthesis.
Removing dead foliage from your tomato plants is important as doing so prevents the plant from sending the available nutrients and water to dying leaves, leading to wasted resources. Water and nutrients can then be diverted to strengthen the shoots and grow new foliage unaffected by fertilizer burn.
Leaves that have started yellowing cannot be saved or fixed. The affected leaves will die, and it is better to remove them to help the plant redirect its available resources towards a swift recovery.
4. Add Mulch to the Soil
Mulch refers to materials like hay, straw, or cover crops that are used on top of the soil and offer a number of benefits, from suppressing weeds to preserving soil moisture. As you already know, maintaining soil moisture can be crucial when your tomato plants are recovering from fertilizer burn.
As mentioned earlier, water is necessary to rehydrate your plants, disperse available nutrients through the plants, restart photosynthesis, and flush excess fertilizer out. The mulch protects the soil from the heat of the sun and reduces water loss through evaporation, which helps your plants rehydrate themselves faster.
Using mulch also prevents the possibility of drowning the roots through overwatering, as the mulch will absorb a lot of the moisture and release it slowly into the soil.
Preventing weed growth is also important in the weeks when your tomato plants are recovering from fertilizer burn. You want all the available resources directed to fixing the issue. Any additional plants in the soil will use up valuable water and nutrients that your plants need to recover, and it is important to prevent that.
Another essential function of organic mulch like grass hay is that it ties up the excess nitrogen in the soil. This phenomenon is helpful for plants that have been overwhelmed by nutrients and subjected to leaf scorch because of excess macronutrients in the soil.
5. Prune Away Dead Roots and Flush the Roots Completely
Cases of fertilizer burn begin at the roots long before they reach the leaves, but you’re only going to notice the issue when it starts affecting the foliage.
Dead roots don’t always need to be pruned away, but if your tomato plants have been severely affected by fertilizer burn, pruning the dead roots and flushing them will help. You can also do this if you want to ensure a shorter recovery time for your plants.
Just as removing the dead foliage helps your plant conserve and redirect resources, removing dead roots helps your tomato plants divert resources to better use. It also helps your plants grow quicker.
Flushing the roots is crucial as the water helps wash away any mineral salts that might be in contact with the fine, fragile root hairs. This doubles the benefits of watering your plants as any excess fertilizer clinging to the roots will be washed away, which helps the plants recover faster.
The newly flushed and pruned roots will be able to uptake water and nutrients far more easily.
Flushing is especially important due to the fact that the fine root hairs are responsible for most of the nutrient and water uptake in your tomato plants. Keeping the root hairs healthy helps your plants take in more water, which is necessary to ensure recovery from fertilizer burn.
The root hairs are also essential for the uptake of phosphorus from the soil, which is the plant macronutrient responsible for root growth. Flushing the roots of plants suffering from fertilizer burn allows them to take in all the water and nutrients required for them to regrow healthy roots.
6. Change out the Potting Soil and Repot the Plants
In most cases of fertilizer burn, flushing the excess fertilizer out of the soil is usually sufficient enough and gets the plants to a place to start their recovery process.
However, if you’re dealing with a particularly bad case of fertilizer burn with significant damage to the foliage, you may need to change out the potting soil entirely.
Of course, this is only possible if your plants are in pots; if they are not, pruning the foliage, flushing and pruning the roots, and flushing out the excess fertilizer are the best steps to take. You might need to scrape any excess fertilizer away from the ground, in which case you have to be careful not to remove too much of the topsoil.
If your tomato plants are planted in pots and show severe signs of fertilizer burn, the best option would be to simply repot them with fresh potting soil. First, water the plants thoroughly a day before repotting them. Remove the damaged foliage to reduce the burden of nutrient dispersal within the plants, then carefully pull your plants out of their pots.
Flushing and pruning the roots is a great idea before repotting your plants, as doing so will position your plant to grow healthier roots in the fresh potting soil and help keep transplant shock at bay.
Use a potting soil that comprises a balanced mix of clay, silt, and sand. Hold off on using any starting fertilizers for your newly repotted tomato plants to prevent any further issues with fertilizer burn.
You can mix in organic fertilizers like manure or compost in with your potting soil to help your tomatoes recover. Adding bone meal will supply phosphorus and calcium to help your tomato plants grow new roots to replace the ones already damaged by the fertilizer salts.
Use a fresh pot for your plants, or wash the original one out to remove any fertilizer salts that might be lingering in it before you repot your tomato plants.
7. Ensure That the Soil Has Good Drainage
Drainage is essential for all plants, but especially so for plants suffering from fertilizer burn. Fixing fertilizer burn involves rehydrating the plant and flushing out the fertilizer from the soil and the plants themselves with repeated, thorough watering.
Plants in soil with insufficient drainage will end up overwatered as their damaged root systems suffocate in the excess moisture in the soil.
Potted tomato plants must be repotted into a potting soil that has a higher proportion of sand and silt to ensure good drainage. Other components of potting soil that ensure good drainage include perlite, coco peat, or peat moss. Incorporating these elements into your potting mix will ensure that all excess water drains out of the pots without drowning your recovering plants.
Compost and manure are also excellent additions to improve the drainage of most soil varieties, and you can use them as a top dressing for your garden soil as well if your plants are rooted in the garden. Dried leaves and other types of mulch can also be used to improve the overall drainage quality of your garden, which will help your tomato plants survive the recovery process much better.
8. Keep the Plant Safe From Sunburn and Windburn
Leaf scorch is one of the most visible symptoms of fertilizer burn, and it leaves your plants weak and sensitive to other damage as well. Apart from fertilizer burn, leaf scorch can be caused in those instances when the sun is too bright or when the conditions are extremely windy.
Protecting your recovering plants from bright sunlight and dry, windy weather is essential to fix the fertilizer burn threatening your tomatoes. You might need to move your pots to a place where the plants can still get about six hours of sunlight, particularly morning light, which is less harsh than afternoon sunlight. Direct sunlight is not ideal for plants recovering from a sunburn.
If you have the resources, you could put up a temporary shade made up of wire and translucent cloth like a curtain to protect your plants from the bright afternoon sun. A temporary shade is an excellent idea for tomato plants that are planted in your garden, especially if your garden is west-facing and receives most of its light in the evening.
Shades will also help with windburn, which can also cause dehydration and scorching in plants, especially plants that are regrowing their leaves.
9. Resist the Temptation To Work on Your Plant
Most cases of overfertilization are not caused by neglect but rather by over-enthusiastic gardeners who want to do everything they can to help their plants thrive. If your tomato plants are suffering from fertilizer burn, clip the dead foliage and roots, water the plants thoroughly, and repot them if necessary.
After you’ve taken the immediate steps required to address the damage to your plants and ensure that your tomatoes are rooted in well-draining soil, you must leave them alone.
One of the hardest things to do, especially when your plants are struggling, is to do nothing at all. However, after you’ve addressed the problem, the only thing you can do is to water your tomatoes thoroughly and regularly and wait. Water as soon as the top two inches of the soil dry out.
You have to resist any temptation to feed your plants for the first 3-4 weeks as your tomato plants regrow their roots.
10. Restart Feeding Lightly After a Few Weeks
Your tomato plants will need about 2-3 weeks to regrow their roots, and even longer if they’ve been repotted. After four weeks, you can start feeding your plant with an extremely diluted solution of fertilizer to help your plants recover completely.
If you’ve incorporated any organic fertilizers in your potting soil, you can go up to six weeks before adding any more compost or manure into the soil.
The wait will ensure that you don’t burn your tomato plants with excess fertilizer again. While slow-release fertilizers, especially organic fertilizers, are unlikely to cause fertilizer burn, using too much can still damage your recovering plants.
Fixing fertilizer burn in your tomato plants is possible as long as there is still some green on your plants. Flush the plants with water and water them often to rehydrate them as they’re recovering.
Remove any dead foliage and roots as necessary, and repot your plants if they’re especially damaged by fertilizer burn. Wait at least four weeks before fertilizing your plants again.
If you’d like a more in-depth guide about fertilizing plants, you can read my other article here: How to Fertilize Indoor & Outdoor Plants (Ultimate Guide)