Does Soil Dry Out While in a Bag?

I have a habit of buying bags of potting soil and storing it for future use. I like having stock because I live far from the store, and I want to be able to grab a bag when I need one instead of driving to the store. Unfortunately, I sometimes leave the bags of soil in storage for too long. 

Soil dries out while in a bag. The bag is exposed to dry air and warm temperatures, which cause the moisture in the soil to evaporate. Fortunately, most soils in a bag contain peat moss which decomposes slowly and retains moisture. However, over time, it dries, and it isn’t easy to rehydrate it. 

In this article, I’ll explain why soil dries out while in a bag and how you can rehydrate the soil. 

How Soil Dries Out While in a Bag

Soil is usually sold in moisture-conserving plastic bags to minimize the risk of drying out. Unfortunately, the packaging offers no guarantee against drying. Soil dries out in the bag for various reasons.

Exposure to Direct Light

Direct sunlight degrades the bags containing the soil over time. The heat impairs the bags, heats the soil, and causes it to dry. This is why soil stored outdoors dries faster than in the basement or garden shed. It is best to store the bag of soil in a roofed area.

High Temperature

High temperatures also cause soil to dry out while in the bag. So, even if the bags are away from direct sunlight, you must be wary of the room’s temperature. The environment needs to be as cool as possible if you don’t want to risk the soil drying before you use it. 

Storage Time

How long the soil is stored will determine how much it dries out. The longer the storage period, the longer the exposure to high temperatures or sunlight. The soil is still good for use up to six months after you open the bag, whereas the soil in sealed bags typically remains in excellent condition for 9 – 12 months.

However, the soil will dry out when stored in poor condition. Instead of waiting too long before using soil exposed to high temperatures, it is best to use it earlier. Once it dries out, the soil quickly becomes hydrophobic

Soil also compacts when it is stored for a long time.  

Rodents

Sometimes rodents chew the bags containing the soil. This exposes them to natural elements. Just like the soil in the open, the ones in bags start drying out without the protection of the plastic bags. 

If you have no plans of using the bags of soil immediately, you need to ensure the storage area is free of rodents. Unfortunately, eliminating rodents from the garden and storage areas can be challenging. 

You can wrap the soil in a tarp to add an extra layer of protection. You can also set up traps and allow your cats and dogs to move freely through the shade to catch unsuspecting rodents. You should also keep the storage area clean and fumigate it occasionally.

How to Rehydrate a Dried Out Bag of Soil

When soil stays in bags for too long or when exposed to elements such as sunlight or high temperatures, they become dry and hard. You shouldn’t use the soil in this state because your plants will struggle to germinate. Even if they do, they may have stunted growth. 

When soil loses moisture and is left dry for long, it starts to repel water. When you put the soil in a pot or spread it in your garden, it is easy to assume it has absorbed the water when you first water it. However, what you have is a runoff. 

You don’t need to dispose of dried-out soil. You can do the following to improve the soil’s condition enough to use it.

  • Add water to the dry soil. Place the soil in a tub and mix it with water thoroughly. Work through the fibers to ensure the water gets into the soil. If the potting soil contains peat moss, break the chunks into smaller pieces to allow them to absorb the water. 
  • Cover the tub with a black plastic bag. As the water evaporates, it will condense on the plastic bag and go back into the soil. Leave the setup overnight to allow the hydrophobic soil to gradually absorb the water.
  • You can also open the bag and add soapy water to the soil without transferring it to a tub. Place the bag outside for a day. Soapy water acts as a wetting agent. So, besides making the soil moist, it will also make it less hydrophobic. 
  • Use a wetting agent. You can use a commercially available wetting agent, but it is best to use an organic one if you have only one or a few bags of dry soil.

Once you are confident the soil has absorbed the water, you can mix it with new bags of soil. Alternatively, you can leave it out to lose some of the moisture before using it in your garden or plant pots. 

Allow the plants to utilize the water in the soil before you start watering the plants.

This video shows why dry soil doesn’t absorb water and how to fix it.

Can You Still Use a Bag of Dry Soil?

You can still use a bag of dry soil in several different ways, especially after rehydrating it. You can use it as a filler for your garden soil or add it to your compost pile. However, you need to sterilize the soil before reusing it.

You must ensure that the soil is void of harmful microorganisms and pests. Chances are, pests and microbes were attracted to your open bag of moist soil before it completely dried up. 

If that were the case, you risk introducing such problems to your garden or compost pile. The best course of action is to sterilize the dried-out soil before repurposing it or using it in your garden.

Sterilizing Dried Out Soil

After performing the rehydration tips mentioned above, you must loosen the dirt and break the compact chunks. It is essential to rehydrate the soil before sterilizing it to ensure that the hot water can reach every part of the soil to eliminate surviving pests and microbes.

You can sterilize the soil by pouring hot water on it. Ideally, you should use boiling water (212 °F / 100 °C) to kill off all pests and microbes in the soil. Work the hot water into the soil using a trowel to ensure that all parts of the soil are soaked in it. 

Cover the setup with a clear plastic bag to retain the heat and prevent new pests and microbes from invading the soil as it cools down.

Sterilizing the soil can also kill helpful microorganisms. You can add the sterile soil to your compost or bury it in your garden to reintroduce beneficial microbes.

How to Store Potting Soil Mix

It is important to know how to store bags of potting soil properly to prevent them from drying out. Soil naturally degrades over time. When buying bags of soil, you need to know when you intend to use them because they typically only stay in good condition for the next 12 months.

To maximize or extend the period you can use your opened bags of soil, follow the tips below:

  • Reseal opened bags and store them in airtight containers.
  • Store the container indoors, away from the sun and moisture.
  • It is best to leave the potting soil in its original package because the bags have moisture-retention properties.
  • If the bags tear, place them in giant ziplock bags.
  • Use large plastic bins if you don’t want the potting soil to take up all the space in your garden shed. The plastic containers also protect against exposure to direct heat and elements in the air.

Conclusion

It is best to use store-bought soil as soon as possible. However, if you cannot use it immediately, you should store it in the right conditions to minimize exposure to elements that will cause it to dry and compact quickly. 

You don’t have throw the soil away when it hardens and dries out because you can still use it. However, you should make it less hydrophobic and sterile before reusing it.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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