Fixing hydrophobic soil in dry pot plants

Often we water our pot plants not knowing that they’re remaining dry under the surface and around the root zone.  If we have hydrophobic soil in our pots, we can add as much water as we like, but without rectifying the situation, they’ll end up dying of thirst.

The good news is that fixing hydrophobic soil in dry pot plants is fairly easy.  Hydrophobic soil is a soil, or a dirt, that repels water.  For more information about what it is, how its caused and how to test for it, read my blog Hydrophobic soil, what is it and what does it look like?

Some packaged potting mixes already have soil wetting agents in them.  Therefore we’ll need to check the labels to see whether or not they do.  Then we’ll need to test them to see if they are in fact ok.

We can develop dry pot plants and dehydration if the soil from previously treated potting mixes is rather old… ie older than 12 months.

We should also test any bulk potting mixes and composts.  I purchase mine from a landscape supplier and some of them are always hydrophobic.  To test whether or not the potting mix is hydrophobic, follow the step by step instructions contained in my blog: Hydrophobic soil, what is it and what does it look like.


Not all soil wetting agents are the same

We can treat our dry pot plants that have hydrophobic soil with soil wetting agents.  Soil wetting agents can be granular or liquid.  They can be organic or inorganic.  They can feed the microbes in the soil or they can kill the microbes in the soil.

Agar agar is an organic soil wetter but fairly pricy to purchase if you’re using a lot of it.  I use a liquid organic soil wetter that has lots of soil goodies in it.

Inorganic soil wetters can break down the waxy substances found in hydrophobic soil but they do not tend to feed the microbes and living beings in the soil. Some are quite toxic and produced from fossil fuels. Others have substances in them that are also used in car and truck engines… So for gardeners who practice mindfulness and for those of us who prefer to practice non-violent gardening, I’d suggest an organic soil wetting agent.


When to add a soil wetting agent to the soil

For dry pot plants that have become hydrophobic: we need to determine whether it’s time to pot-up that plant. Has the plant outgrown the pot and will it benefit from potting up to a larger pot?  If so, we can address the hydrophobic soil issue after we pot-up.  I’ll discuss how to pot up a plant in another blog post.

Hydrophobic soil can seriously affect a plant depriving it of vital water and other nutrients.  If the plant is too dehydrated and stressed and potting up is likely to cause further harm, I’d use the soil wetter prior to potting up.  We need to get the plant’s state of healthy back up before we subject it to the stress of potting up.  I’ll walk you through that process below.

If we’re not going to pot up, we can simply dilute the soil wetting agent as instructed on the product’s label.  We then add that solution to the soil using a watering can.  Once the water has disappeared, check under the surface of the soil to make sure it’s penetrated.  Another application may be required.


How to fix a seriously dehydrated pot plant

If we’ve got a seriously suffering plant it is likely that the soil is completely hydrophobic and in that case I’d usually soak the pot.  We do that by filling a bucket with the appropriate measure of soil wetter and water.  Fill the bucket to just over the height of the pot.  The soil wetting agent label will tell us what amount of soil wetter to use per litre of water.

Once we’ve done that, gently lower the pot plant into the bucket and notice it float on top of the water. The higher it sits, the more hydrophobic the soil is. You can splash the water mix onto the top of the pot to assist the process.  If the pot is still floating after a few minutes, gently push it underwater until it stops rising.

Once the wetting agent has soaked the soil the pot will sit naturally on the bottom of the bucket.  Don’t leave the plant in the bucket for too long. Just long enough for it to sit naturally on the bottom. That indicates that there isn’t much air left in the soil – time to drain the pot and let air back in.  If we leave it in for too long, any worms and bugs and microbes will start drowning.  We don’t want that.

You should only need to do that once. Depending upon the product we use, we may need to use our watering can and add our organic liquid soil wetter annually.

I make it a habit to check my pot plant soil on a fairly regular basis to make sure the soil isn’t becoming hydrophobic.  To do that, you simply follow the test laid out in the blog: Hydrophobic soil, what is it and what does it look like.


How to add a liquid soil wetting agent to a new plant, cutting or seeds in a pot

Mix the appropriate amount of soil wetter into a bucket of water. The label will tell you what the appropriate measurement is.

If the compost or potting mix is new and you are potting a plant, cutting or seeds for the first time. Simply fill the pot with the compost or potting mix and place the plant, cutting or seed into the pot.

I’ll cover how to do these things in detail in another blog.  For now, I’m going to assume we all know how to do these things.  If you don’t: make a comment below and I’ll start writing that blog post.

Now, with the soil and plant/cutting/seed in the pot we can simply water it in using the appropriately mixed organic liquid soil wetter.  It should soak straight into the soil.  It’s as simply as that.


1 Comment

Follow These Steps When Repotting a Fiddle Leaf Fig - Grow It Inside · February 10, 2021 at 5:33 am

[…] not much soil left to hold moisture or your soil has become hydrophobic. Yes it’s a real thing, soil can become hydrophobic. Conversely, your plant could be staying moist for too long if the pot is too big or you are […]

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