Over-fertilising your houseplants can actually have quite damaging effects but it’s quite a difficult issue to diagnose. This is because once you’ve over fertilised, there aren’t so many ways to actually confirm the issue compared to watering problems where the soil and root system will give you a few hints.
This is why the issue of too much fertiliser often gets overlooked so we are bringing you this article to go through the different symptoms of over-fertilisation and how you can fix it.
Symptoms of over-fertilising your houseplants
Yellow leaves can indicate over-fertilisation
The most common symptom of too much fertiliser is yellow leaves. Depending on the severity of the problem this can show up as yellow spots, patches or entire yellow leaves. This is described as fertiliser burn which means the problem has been going on for a little while. Usually, it is the root system that is first impacted, then the problem will soon become visible across the plant.
It’s important to note, however, that yellow leaves are a common symptom of a variety of issues so don’t use this as the only confirmation that you are over-fertilising. Overwatering, sunburn and natural ageing can also have a similar effect.
To know whether the yellow leaves on your plant are caused by fertiliser burn, check over your plant for any of the below-mentioned issues and check the soil moisture, light levels and any changes in the environment that might indicate something else is wrong.
Brown leaf tips can also mean over-fertilisation
Another common symptom of over-fertilisation is brown leaf tips and edges. Similarly, with yellow leaves, this is also caused by watering and humidity issues so it’s important to do some further investigating to fully make your diagnosis.
Usually, brown leaf tips and edges are one of the earlier signs of fertilisation and can often mean the issue hasn’t fully taken over your plant and can be solved fairly simply. This is why it’s very important to get to the bottom of whether or not fertiliser is causing the brown tips so you can treat your plant accordingly.
There is visible excess fertiliser on the soil
If you notice a white crust or powder forming on top of the soil then this can indicate you are over-fertilising and the excess minerals have clumped together. This can be quite damaging to your plant as the excess fertiliser can form around the roots, suffocating them and severely impacting the health of your plant.
Your houseplant is losing leaves
Another symptom of overfertilisation is actually a loss of leaves. This happens when the root system is so badly damaged from the fertiliser that it cannot sustain that level of healthy growth anymore.
If your plant is losing leaves due to fertiliser issues it means the problem has been slowly developing for a while so it may be more difficult to revive your plant and bring it back to full health. Acting quickly is crucial here and we have written the steps to solving over-fertilisation below.
Too much fertiliser can cause stagnant growth
Another sign of too much fertiliser is if your plant has stopped growing during the growth season. It’s quite an ironic issue as most of the time plant parents fertilise their plants to get more luscious growth but too much fertiliser actually does the opposite.
Note that during winter and autumn, growth levels in houseplants drop as they become dormant. So don’t mistake this lack of new leaves for an issue – it’s totally normal!
How to fix an over-fertilised houseplant
Now that you have diagnosed the issue and confirmed that your plant is suffering from too much fertiliser, we’re here to tell you how to fix the issue and get your plant back to full health.
Remove fertiliser sticks from the soil
If you are fertilising your plants through fertiliser sticks, then remove these from your plant immediately. This will prevent your plant from getting any more fertiliser and should be enough to solve the issue. Monitor your plant and make sure all other environmental factors are giving your plant what it needs.
Flush the soil
If you have used fertiliser pellets mixed into the soil or liquid fertiliser diluted into the water, then one way to remove the excess is to flush the soil. The best way to do this is to place your plant in the sink or shower (depending on size) and run water through it for several minutes. Make sure that you leave your plant to drain for a few minutes afterwards so that you aren’t returning your plant to its planter with super soggy soil.
Replace the potting mix with fresh mix
If the issue has severely impacted your plant’s health then it’s probably best to replace the potting mix. This ensures that there isn’t any lingering fertiliser pellets or liquid fertiliser in the soil that could continue to harm your plant. Discard the old potting mix as you don’t want to re-use it again for other plants if it’s full of fertiliser.
How to prevent over-fertilisation from harming your plant
Adjusting your fertiliser schedule
Make sure that you hold off fertilising an over-fertilised plant for about 6 months or in the following spring, whatever comes second. This way you are giving your plant enough time to recover from the shock and stress.
Then moving forward, you want to reduce the frequency or amount that you are fertilising your plant to prevent the same issue from reoccuring. Remember, a lot of plants will still reward you with plenty of new growth without any fertiliser at all. Having the right environment will have a lot stronger effect on new growth than additional fertiliser so it’s optional.
We hope this guide has been useful for you to help spot the signs of over-fertilisation as well as fix and prevent the issue as well. It’s definitely not an easy problem to diagnose but if not treated can cause some aesthetic and problematic problems for your houseplants.
Written by Billy Dawson