When you have an excess amount of unused potting soil, you tend to let it sit in your shed, especially over the winter. However, you may return to it next season to find that it has dried out. Whether it’s still useful or not for gardening depends on a few factors.
Your potting soil is still good if it dries out. Just rehydrate it accordingly and sift through it to remove any dry clumps. However, soil that does not hydrate after numerous attempts may be hydrophobic. If your soil has become compacted, it may require a little more help.
In the rest of this article, I’ll explain everything you need to know about dry, compacted, or hydrophobic soil. I will then discuss how to address it when it happens and how to keep it from becoming a major problem in the future. Let’s get started!
How Soil Becomes Dry, Compacted, or Hydrophobic
Is your potting soil dry and crusty? Have you noticed that your plants aren’t growing as well as they used to? You may be dealing with hydrophobic soil, otherwise known as “dry” soil. Hydrophobic soils are often caused by compaction, which is when soil particles clump together after drying out.
Compacted soils can’t support healthy root growth, and the longer they remain hydrophobic, the bigger the problem becomes.
When potting soil dries out, water repellent “hydrophobic” areas develop. This occurs when the surface tension of the water evaporates faster than it can penetrate through the soil, causing wet areas to have a higher concentration of hydrophilic (water-loving) surfaces than dry areas with greater exposure to air.
As a result, the dry soil particles clump together and become hard and compacted.
The longer dried soil remains hydrophobic, the bigger the problem becomes because as it continues to dry out, it will become more difficult to rehydrate.
How Soil Compaction Happens
Soil particles that clump together after drying form a hard, compacted layer called the crust, which is usually caused by repeated watering.
When you water your plants daily, it causes the soil around the roots to become wet and soft. As soon as it dries out again, it will shrink back down and compact into itself, leaving less room for air pockets between each particle of dirt.
That’s why the soil should be allowed to dry out somewhat between watering sessions so it doesn’t have time to compact too much before getting wet again.
Heavy equipment or vehicles can also cause soil compaction. Large machinery such as tractors or cars can cause serious damage if they aren’t used properly — especially if they’re being driven over unprepared soil.
Compacted soil can also be caused by walking around on the soil. If you’ve got kids or pets (or even squirrels) who constantly stamp all over your soil, there’s a chance they’re the ones compacting it.
Does Potting Soil Expire?
Like many other things, most types of potting soil have an expiration date. You can usually find this on the package somewhere, and keeping this in mind before using the soil is essential.
Dried-out soil can sometimes be an indicator that your soil has expired.
If it hasn’t been used for a while, it might expire quicker. You can expect to find potting soil that has expired prematurely if you left the package exposed to the elements. If you’re not planning to use your potting soil immediately, try to store it in a cool, relatively humid place to prevent premature expiration.
Signs Your Potting Soil Has Expired
If your potting soil is parched and has an odor, you might find that it has expired. A bad smell is usually a negative indicator, so don’t repot your plants in the soil if it smells a bit eggy.
Additionally, an insect infestation is another telltale sign that the potting soil is expired. This can escalate the drying out of the mixture and make it even less likely that you’ll be able to save it since an infestation sucks out moisture.
How To Deal With Dry Potting Soil
When you notice your soil drying out, you should address it as soon as possible. Otherwise, the problem will become increasingly difficult to deal with. There are a few ways to take care of the soil that has dried out.
Determine How Much Hydration Your Soil Needs
Knowing how much water to give your plants isn’t always easy, especially if you’re new to gardening or you’re growing plants in containers.
I highly suggest getting a moisture meter if you’re worried about the moisture of your plants. Moisture meters go a little bit into the soil of your plant, read how much moisture is available, and indicate it for you on a digital screen.
It’s pretty intuitive to use: Just stick the long end into the soil, and you’re good to go. The one caveat is that it won’t work if your soil has become too hard.
Even without a moisture meter, you can still get a good sense of your soil’s moisture levels as follows.
- The finger method: Simply stick a finger down into the dirt and feel for moisture and dryness. I should note, however, that this method doesn’t work well if your soil is compacted or hydrophobic. If your finger can’t break through that top layer, your soil likely has a compaction problem.
- Check the root ball of each plant every few days (or as often as you can). If the roots start to feel dry when you touch them with your fingertips, give them another soak, but be careful not to overwater. Once they’re damp, wait until they feel dry before giving them another drink. This method can be invasive for your plants, but if your dry soil isn’t giving you any clues, it may be your only option.
Throw Away Infected Soil
If your potting soil has a whole host of other issues, consider tossing it. For example, any mold, pests, or mildew accumulating in your soil can cause problems more significant than dry soil. These aforementioned issues often come with compacted or hydrophobic soil.
While it is possible to save infected soil, I always recommend taking on each battle one at a time. For example, if you don’t have the resources to get new potting soil, you can deal with pest issues first, then watering problems, and finish by protecting your soil against mold and mildew.
Again, if you’re having all of these problems simultaneously, you can bet that the cause is overwatering.
Rejuvenate Your Soil
There are numerous ways to deal with hydrophobic soils. Introducing new soils into your mix or ensuring you’re watering evenly can usually eliminate this problem once and for all.
You can also attempt to:
- Add compost or peat moss to loosen up the soil.
- Add sand or perlite for aeration on top of any other amendments you’ve added.
- Toil through the soil and break down any clumps.
- Remove some soil from the pot to make the soil less compacted.
- Ensure proper drainage is occurring.
If all of this fails, you can always repot your plant into a new batch of soil.
How To Avoid Drying Out Soil
The best way to deal with the problem of dried-out soil is by not letting your soil dry out completely in the first place.
However, if you’ve had a particularly hot summer or live in an area with high humidity, your soil may get wetter than usual, and the air will be trapped inside when it dries out again. This can cause compaction even if you’re watering regularly.
Soil needs to be moist enough that the top ½” (1.27 cm) of potting soil is damp but not wet. You can usually test for this with your finger.
If your potting mix dries out too quickly (especially in hot weather), the roots will die or slow down growth because they aren’t getting enough oxygen from the air pockets created by good drainage at each level when watering properly.
Drainage is essential for healthy soil as well. If your plant pots are stylish but don’t have any holes at the bottom to help the plant release soil, you’ve got a problem. This may cause compaction issues, as excess water has nowhere to go and will clump your dirt together.
That’s why you should always check flower pots for drainage.
Watering frequency and depth are the most important factors in keeping soil healthy. When you water, let your pot drain thoroughly before filling it again. If you don’t, you’ll end up with stagnant water in the bottom of your pot.
Potting mixes with too much sand or large particles can be especially susceptible to this problem, so if that’s what yours is made of (or even if it isn’t), consider adding extra perlite to keep soil from compacting as much over time.
Signs Your Potting Soil Needs Rehydration
It isn’t usually that difficult to tell if your potting soil has dried out, but if you’re unsure, there are a few crucial ways you can tell:
- The potting soil looks very crumbly. The texture might feel very rough when it should feel soft between your fingers.
- Your potting soil has changed color. It should be dark brown in color, so if it’s become lighter, it might need rehydration.
- The soil clumps easily. When you squeeze a bit of soil in the palm of your hand, it should remain moist and clump for a few seconds. If it doesn’t, it might need a bit of TLC.
- Your soil moisture probe says so. Using a soil moisture meter can be helpful if you’re a beginner and unsure what to look out for.
Thankfully, soil moisture meters are not particularly expensive, and they can be a lifesaver for your soil.
How To Rehydrate Potting Soil
Now that you’ve determined why your soil has dried out, and you’re in no doubt it needs some extra attention, you can get to the rehydration process.
The concept is pretty simple.
If your potting soil is too dry, it needs some moisture to come back to life. However, this won’t work if your soil has expired. But if you’re sure it’s still good, you can get on with the rehydration process.
Thankfully, rehydrating your dried-out soil doesn’t require special tools, and you won’t need to spend a dime. The only thing you’ll need to invest in is time, and the more dried out your soil, the longer the process can take.
To rehydrate your potting soil, carefully follow the instructions below:
- If it isn’t already, put the potting soil in a pot with drainage holes at the bottom. Make sure the holes aren’t too big since this will allow too much water to escape.
- Using a fork or a small trowel, rake out the soil from top to bottom to ensure it’s evenly separated. This will help the rehydration process along, allowing proper distribution of moisture.
- Put the pot inside a big container, such as a pail or a bucket, and fill the container with water. Leave the soil inside the container until no more bubbles are present.
These directions should give some new life back into your soil. However, if this doesn’t work, the potting soil likely isn’t worth using because it’s most likely expired. In this instance, invest in some new soil and get back to tending to your plants.
How Do I Store Potting Soil After Opening a Bag?
To store potting soil after opening a bag, you should place the contents inside a sealable container like a storage bin. It should be adequately sealed to prevent moisture from escaping and drying out the soil.
You can use any kind of plastic container as long as you can seal the top and it is big enough to hold many bags of potting soil.
However, remember that potting soil is usually best stored in its original container or bag.
If you’re not planning to use it immediately, resist the temptation to open the bag. Instead, place the bag somewhere dark and cool to keep the moisture intact until you’re ready to use it.
One thing to watch out for is mold. It can be frustrating to think you’ve successfully stored your potting soil, only to find it has been destroyed by mold in a few months. An excellent way to prevent this problem is to allow the bag to sit for a few hours in a warm area before sealing the contents in your plastic storage container.
Storing your potting soil correctly will ensure you can reuse it repeatedly, so you won’t have to buy a new mixture every season. This is essential for those on a budget and can save you a lot of cash.
However, if you do intend to reuse your potting soil next season, you might want to add some extra nutrients when the time comes to rejuvenate the soil and ensure it gives enough nutrients to your plants.
Conclusion
Dried potting soil shouldn’t be too much of a problem, but it’s important to watch for compaction in your potted plants. Compacted soil, whether in a small succulent or a large crop of flowers, is dangerous for your plants.
Make sure to water your plants accordingly to avoid soil drying out and give all of your plants proper drainage to release extra water.
