Is leaching important for your plants and why should you do it?
That is a great question!
What is leaching? Why do you have to do it?
Leaching because of soluble salts
If you’ve ever had a spider plant tip look like the one below, you’ve battled soluble salt damage.
Or if you’ve ever had a leaf collapse over the side of a pot and turn mushy, you’ve battled soluble salts. This African violet below is an example.
What are Soluble Salts?
Soluble salts are minerals dissolved in water.
When you water your plants and the water dries up, minerals or soluble salts appear. Often they build up on the edges of the containers.
If your container is terra cotta they come through the sides of the pots. A white crusty residue is the result.
These pots are popular for use in home decor.
Where do they come from?
As mentioned above, soluble salts are from mineral build-up from water. They originate from your tap water, but also from what you add to your water.
Fertilizer is the culprit. Fertilizers contain soluble salts and if overused, it will be a problem. Never use more than the label recommends. More is NOT better.
If you use organic fertilizer the salt buildup will not occur. Use fish emulsion or some other organic fertilizer.
Soluble salts on ceramic pots
This buildup while obvious on terra cotta pots is often missed on glazed ceramic pots. The salts aren’t seeping through the walls of the pots like they do with the unglazed terra cotta.
Watch this video below to see how I remove the crusty residue from ceramic pots. I use white vinegar and soak my pots.
Wick-Watering and leaching
Soluble salt buildup happens most often when a plant is wick-or bottom-watered.
The water soaked up into the container from the bottom of the plant moves the minerals upwards. When a plant is top-watered, the water applied soaks downward through the soil, exiting the plant via the drainage hole. This keeps the minerals from building up.
So if you wick- or bottom-water your plant, leaching them becomes an important part of your plant care. The plants below are being wick-watered on the left and bottom-watered on the right. African violets are often bottom-watered.
Leaching Your Plant
This is when leaching comes in. A wick-or-bottom watered plant needs leaching every 4-6 months.
What does that mean?
Water from the top, allowing the water to run through the plant for an extended period.
Don’t give it only enough water to “water” the plant. Let the water run or leach through the container for a long time. This allows the minerals to flush from the soil as much as possible.
Softened Water
If you have softened water, which has salt added to it, do NOT use it for your plants.
Like ocean water, which is undrinkable, softened water is “undrinkable” for plants. It may not kill them right away, but in the future, it will.
Signs of Soluble Salt Damage
What are the signs your plants have salt damage?
The most obvious sign is brown tips on your plants.
Some plants are more susceptible to this, such as the spider plant.
Your plant may drop lower leaves, have reduced growth, or wilt. When a plant wilts, it means it is dry. Right? Yet, it may be that the salts have built up in your potting mix to the point it affects the roots.
It may draw water from the roots, killing the root tips and rotting the roots. This is an extreme example, but it can happen. If your plant has no roots, it has no water so it wilts. No amount of water will bring your plant back to life.
Repotting Your Plant
If you repot your plant on a regular basis, the mineral build-up won’t occur.
Wash your container and replace the potting mix.
Even if your plant doesn’t need a larger container, it is a good idea to refresh the potting mix every few years.
Conclusion
- Leaching your houseplants is a good thing to do.
- Apply fertilizer following the label. More is not better and I use less than is called for.
- Organic fertilizer is a good alternative to synthetic fertilizers.
- Repot your houseplants once in a while and pay attention to your plants to catch a problem early.
Have a great week, plant friends!
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Just wondering – when you say to leach by running water through for a “long” time, does that mean a minute? 5 minutes? 10 minutes? longer? It’d be helpful to have a ballpark actual time. Thanks so much for your help.
Hi Sara,
I guess it depends on the size of the pot and I may go back and edit that. Thanks for pointing that out. I would keep the water running for a few minutes. Five is definitely enough.
Lisa
We have a water softener that uses salt. I’ve been using a Brita filter to filter the water before I water my plants. Does this remove any of the salt?
Hi Bonnie,
I’m not sure about that, but I doubt it will remove the salt. Use distilled water or if you have an outside spigot you can use or a bypass faucet…? Don’t use that softened water, though.
Lisa