Salt buildup can be a sign of overfertilizing in your plants. Some plant types are more sensitive to this than others. It can also be indicative of other problems such as poor drainage or underwatering.
SIGNS YOUR PLANT HAS SALT BUILDUP
A white, chalky substance forms on the soil surface
Your plant may have yellowing or browning leaves
Burnt leaf tips/edges
Drooping of the plant
Wilting leaves/ leaves falling off
The salts that build up in plant soil aren’t the same as our typical table salt, NaCl (Sodium Chloride). A salt is essentially just a solid that can be dissolved in water. Fertilizers contain other types of salts like potassium chloride and ammonium nitrate. Some soil types naturally contain more salts than others. Alongside this, hard water from your tap can contain many salts which can be harsh on your plant.
Shallow watering also increases the risk of salt buildup forming, as salts are not flushed out of the soil as they would be if you water thoroughly instead.
Salt buildup is more likely to occur during summertime, when your plant’s water needs are higher than usual due to the increased temperatures. Because of this, water uptake is increased, and so salts are also taken up at a faster rate than normal.
WHAT TO DO NOW
To alleviate salt buildup, first manually remove as much of the salts from the soil as possible
You may be able to scrape away the surface buildup, but in order to properly remove the salt buildup from the soil, you’ll need to flush/leach your plant
Place your plant somewhere where water is able to drain away, such as your bathtub or sink, or outside
Pour slightly warm water over the soil - do this carefully so that it doesn’t overflow the plant pot’s edges
You’ll need to use a lot of water - much more than you would normally water your plant with. This is to ensure that you thoroughly flush out the salts from the soil
If you don’t normally, then start watering your plant over the soil (instead of, e.g. bottom watering) to try and prevent salts from building up again
You may wish to hold off fertilizing for a while to give your plant the chance to recover
WHY IS SALT BUILDUP BAD FOR MY PLANT? Excessive salts in your plant’s soil may damage its sensitive roots by causing them to become dehydrated. As a result, the tips of the roots may break off, which in turn can then lead to root rot - this is very difficult for your plant to recover from. Other problems can also occur, such as stunted growth and damage to leaves and flowers. This is because the salts can interfere with the plant’s ability to uptake water, which it needs in order to live.
ARE MY PLANTS AT RISK? As long as you follow Planta’s care schedule, you should be fine. However, if it’s a particularly hot summer, or if you frequently only shallow water your plants, you may want to keep an eye on them to make sure that salt buildup doesn’t occur. Also, if you live close to the coastline and your plants are outside, salt spray damage may occur on their leaves. If possible, try to shelter your outdoor plants from coastal winds.