I was recently given a beautiful white flowering African violet. I love it! As you can see, it is planted in a clay pot. Let’s discuss clay pots, soluble salts, and what they can do to your plants, especially African violets.

White flowering African violet

This African violet is living in a clay pot and the white residue you see are soluble salts leaching out of the pot.

Clay pots-are they always the best choice?

I love clay pots because they are classic, look good with most plants, and allow the plant to be the star of the show. I do use a lot of colored pots, too, though, because I love color. Anyway, I digress…. The problem with using clay pots is the fact that soluble salts can build up in the pot and damage your plants. As you can see below, the African violet leaf resting on the edge of the pot is getting “burnt” from the salts in the pot.

What are soluble salts?

Soluble salts are minerals dissolved in water and quite often, these come from fertilizer residue.  When you dissolve fertilizer in water and give it to your plants, the water is used by the plant and some evaporates, leaving fertilizer residue behind as soluble salts. Fertilizing is a good thing, though, right? Yes of course it is as long as it is done correctly.

Jack's Classic fertilizer

Jack’s Classic water-soluble fertilizer

Soluble salt damage

If there is a build-up of soluble salts in your potting medium, what kind of damage can you expect to see? Some symptoms your plants may exhibit are stunted growth, wilting, leaf burn on the margins, yellowing new growth, small flowers and maybe just reduced growth if the build-up is minimal. The most common plant that exhibits problems with soluble salt build-up is the spider plant. How many of us have spider plants with brown tips?

burnt tips on souder plant

Spider plants are especially sensitive to salt damage

Root damage

Wilting can occur because the soluble salts become concentrated in the potting medium, drawing moisture from the roots of the plant. The roots dry out, die, and the plant collapses, making you believe it needs more water because it has wilted. It technically does need water, but the roots can no longer supply it, so it collapses and will eventually die. This is often referred to as “root burn.” This is the worst-case scenario, so let’s hope it doesn’t get that bad.

Back to the African violet in the clay pot

Clay pots are porous, meaning water evaporates through the walls of the pot, unlike plastic or glazed pots. Therefore, if the water is evaporating through the walls of the pot, the salts are also coming through the pot walls. As you can see below, where the leaves were touching the edge of the clay pot, the soluble salts damaged them, to the point of death.

Address the problem

So how can this problem be solved? In the case of the African violet in the clay pot, the first thing to do is repot the violet. Plastic azalea pots are better for your violets and you can see the difference between a standard size pot and an azalea pot below. Azalea pots are shorter than standard pots and violets grow well in them because of their shallow root systems. Glazed pots are also fine.

 

standard and azalea pot

An azalea pot is shorter than a standard pot.

After repotting your plant into a different pot, water the plant from the top, making sure it runs out the drainage hole. Many people water African violets from the bottom (I see it is called butt-chugging now-who thought of that?!) and as the water is drawn up to the top of the pot, the salts are also drawn to the top. (It is okay to get African violet leaves wet as long as the water isn’t too cold, contrary to popular belief.) If drawn to the rim of a clay pot the violet leaves get damaged. If you prefer to bottom water, its fine as long as every few months, you leach the soil by running a lot of water through the soil from the top, flushing any excess minerals out. It is also a good practice to repot your plants using fresh potting medium on a regular basis. You don’t have to put them into a larger pot, just repot with fresh medium.

Cleaning pots

This can happen on pots other than clay but usually isn’t as bad, as the pots aren’t porous. If you see a crusty build-up on your plastic pots, take the plant out of the pot and scrub your pot. Stubborn crust can be removed by soaking your pot in vinegar. Wash and rinse well before putting a plant back in the pot. Clay pots can be soaked with a solution of 1 part bleach to 9 parts water and is a good idea before reusing them on a normal basis.

soluble salt damage

Two leaves have been killed by soluble salts in the clay pot

Hopefully, your plants are all doing fine and no soluble salt damage is occurring. If you have had, or are having these problems, I hope this helps.

Have a great week, my plant friends!

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