Oasis Cubes Vs Rockwool: Which One To Pick For Hydroponics?

When growing hydroponically, one of the most critical decisions is choosing a grow medium. Oasis cubes and Rockwool are two great options that have their advantages. But oasis cubes vs Rockwool: which one should you use for your hydroponics? And how do you know which one is suitable for your plants?

Choosing a growing medium will depend on the type of plant you are planning to grow, the pH of water irrigation, cost, and the type of hydroponics system used. However, a good growing medium should provide your plant with all they need, including oxygen, water, nutrients, and support the growth of their roots.

Read on to find out everything you need to know about oasis cubes and Rockwool growing media, their pros and cons, and finally decide which one fits best your needs.

See also: Top 3 Most Effective DWC Nutrients.

Oasis Cubes Vs Rockwool: Which One To Pick For Hydroponics? – plantsheaven.com

Table of Contents

What Is Hydroponics?

Hydroponics is a new and developed agricultural technology that uses nutrient-rich water as a growth medium instead of the normal soil medium. It is one of the best agricultural techniques that support the fastest growth in a limited span of time. 

There are a number of reasons for choosing this technique over the raw soil-based typical agricultural methods. The advantages of hydroponics include better space allocation, climate control, and pH control, which is less labor-intensive.

Read this article to learn the differences between hydroponics and soil gardening, including their advantages and disadvantages.

The hydroponics techniques include 6 types of hydroponics systems, including:

The core method of hydroponics always remains the same but variations may occur. One of the variations includes the selection of growing medium.

See also: How To Effectively Choose Hydroponic Pumps?

How To Choose The Perfect Growing Medium For Hydroponics?

  • A proper growing medium should have adequate aeration and drainage. Every growing medium must have good water retention and provide good drainage. Choosing a proper growing medium will help you prevent excessive water retention and the absence of aeration within the medium.
  • Durability: A growing medium must last longer. Try to avoid soft aggregates that disintegrate quickly. 
  • A suitable medium should be sufficiently porose. Look for a growing medium that can remain damp enough from the nutrient flow for plants to absorb all their needed nutrients between cycles.
  •  Clean and sterile growing medium: You will minimize the spread of both diseases and pests with a clean medium. There are some growing mediums that you can reuse by pasteurizing them at 180 F for 30 minutes or using a 10% bleach soak for 20 minutes, then rinsing them in tap water several times.
  • Chemical properties. Neutral pH and the ability to hold nutrients.

What Are Oasis Cubes?

Oasis cubes (AKA Oasis foam cubes) are a brand of medium made from water-absorbent phenolic foam, also known as floral foam. Generally, oasis cubes serve as a growing medium designed for seeds and cuttings and plant propagation

Mainly, oasis cubes are used for the fast germination of crops, including the following crops:

  • Lettuce 
  • Cole crops (cabbage, collards, and kale), 
  • Onions and alliums, herbs
  • Tomato 
  • Eggplant seedlings.
Oasis Cubes Vs Rockwool
Oasis Cubes Vs Rockwool: Which One To Pick For Hydroponics? – plantsheaven.com

Advantages of Using Oasis Cubes

Like anything in life, oasis cube has both pros and cons. Here are the advantages of using oasis cubes.

1- Oasis Cubes Offer a Neutral pH.

Because oasis cube growing medium in hydroponics has a neutral pH, it is perfect for growing plants since it creates a more natural environment and prevents the growth of harmful bacteria and fungus.

Depending on your specific plant’s requirements, you can use acid or alkaline modification to adjust the pH level.

2- Oasis Cube Has a Great Water Retention Capacity.

Oasis cube will hold proper moisture and nutrients around the roots without becoming too wet or dry.

In addition, it is also porous enough to help let the oxygen circulate while still supporting your plants’ health and growth.

3- Oasis Cubes Are Not Expensive and Do Not Require Pre Soaking.

Oasis cubes are easy to use and require less maintenance than other growing media. In addition, they are easier to irrigate.

Moreover, oasis cubes do not require to be pre-soaked in water before planting. They are generally hydrophilic and will absorb a lot of water on their own.

Additionally, you can adjust the height settings on the cubes to adjust different plants, which makes it a versatile growing medium.

Disadvantages Of Using Oasis Cube

Now, let’s discuss des disadvantages of using oasis cubes.

4- Oasis cube Is Not Suitable For Plants That Need a Lot Of Nutrients.

Oasis cube is not suitable for plants that need a lot of nutrients because their compressed foam material doesn’t hold as many nutrients compared to other hydroponic growing media.

If you choose to use oasis cubes, you will most likely need to provide your plants with additional liquid or solid fertilizers.

5- Oasis Cube Has Limited Value Beyond Seed Propagation And Germination. 

The use of oasis cubes is limited beyond seed propagation and germination, and it is of limited value.

6- Oasis cube Can Break Off and Clog Your pump Filters.

Some gardeners have said that oasis cubes can get compacted and lose their porosity over time which can reduce the oxygen available to the roots.

What Is Rockwool?

Rockwool growing medium is made by melting basaltic rock and spinning it into delicate fibers with easy-to-use cubes and blocks. It was first tested as a soil substitute in the late 1960s by Scandinavian and Dutch greenhouse growers resulting in a revolutionary expansion of Rockwool-grown plants worldwide, according to the Oklahoma State University.

Rockwool is among the most popular growing mediums used by hydroponic growers. It offers numerous benefits. It retains moisture well, reducing the risk of underwatering. It also retains oxygen well, reducing the chance of overwatering. It never impedes the development of roots.

Oasis Cubes Vs Rockwool
Oasis Cubes Vs Rockwool: Which One To Pick For Hydroponics? – plantsheaven.com

Advantages of Using Rockwool As a Growth Medium

Similar to oasis cubes, using Rockwool as a growth medium also comes with advantages and disadvantages. Let’s discuss the pros first.

1- Rockwool is Safe.

Made of natural materials, Rockwool has no harmful chemicals. It is safe to use as a plant-growing medium.

However, human exposure to Rockwool may cause health issues because of its physical properties. Be extra careful when handling Rockwool because it can irritate the skin, eyes, and lungs. Too much exposure to the skin might even cause serious long-term effects.

But like anything in life, Rockwool also comes with disadvantages.

2- Rockwool Has a Large Water Retention Capacity.

Rockwool is highly moisture retentive and provides excellent aeration, which gives your plants’ root system plenty of oxygen (about 8% to 25% air, according to the Oklahoma State University) as long as you don’t completely submerse the growth medium.

3- Rockwool Is a Convenient Choice For Various Hydroponic Applications

Rockwool is a convenient choice for different hydroponic uses because it is available in multiple sizes and shapes.

Rockwool breaks apart quickly, and you can adjust the sizes to meet your needs. In addition, you don’t have to worry about your Rockwool substrate degrading and breaking down and clogging up your system’s components overtime throughout the growing cycle.

Structurally, Rockwool does not break down for about three to four years, according to Oklahoma State University.

See also: 22 Pros And Cons of Hydroponics (Should You Grow Hydroponics? Find out!)

Disadvantages of Using Rockwool As a Growth Medium

Here are the disadvantages of using Rockwool as a growth medium.

4- Rockwool Has No Nutrients, Organic Compounds.

Rockwool contains no weed seeds, disease pathogens, or pests, which means it has no nutrients, organic compounds, or microbes.

Generally, if you use Rockwool, you will need a balanced and complete hydroponic solution to meet your plants’ nutritional needs.

5- Using Rockwool Might Lead To Overwatering. 

Because of its physical structure, Rockwool drains excess water fast. However, it also retains small amounts of water near the bottom of the cube. This unique Rockwool property enables plants to attain adequate hydration while letting more air circulate and oxygenate the roots. 

This difference in moisture levels between the top and the bottom of the cube makes Rockwool an ideal growing medium for hydroponics. Still, it can also make it challenging to determine when to water the plants, resulting in over-watering.

Pro Tips For Properly Watering Plants in Rockwool Growing Medium:

  • Put about 2 to 3 seeds in the hole at the top of the Rockwool growing medium. 
  • Water your plants using a hydroponic nutrient solution. 
  • When your plants grow about 2 to 3 inches (5 to 7.6 cm.) tall, you can transplant them into the soil or place them in a hydroponic garden

6- Rockwool Is Not an Environmentally Friendly Growing Medium.

Since Rockwool is made of rock derivative, it doesn’t break down or erode over time, meaning you can use and reuse it several times. In other words, Rockwool is not biodegradable, it will last forever in a landfill; therefore, using Rockwool for plants can cause environmental issues.

If you are worried about Rockwool environmental issues and still want to get the benefits of Rockwool in your hydroponic garden, try to use fewer new Rockwool cubes every growing season.

Instead, thoroughly and carefully rinse your old Rockwool cubes of any organic material and reuse them. It will reduce environmental issues, and it will also save you a great deal of money.

See also: Must Know About Wick System Hydroponics.

7- Using Rockwool as a Growth Medium Might Lead to pH Balancing Issues.

Rockwool is generally much more alkaline than other media, meaning that you may have to make some adjustments to your nutrient solution pH to create an ideal pH for your plant’s root zone.

Using Rockwool as a growth medium might lead to potential issues as you might be required to create one pH-balanced nutrient solution for one media and a separate one for your Rockwool-grown plants.

In addition, Rockwool can quickly shift its pH balance, which means that you may have to pay extra attention to your pH balances and regularly adjust if required.

Pro Tips:

  • Rockwool typically has high pH of 7 to 8. 
  • Ensure you prepare a solution of little acidic water (pH between 5.5 to 6.5) by incorporating several drops of lemon juice with pH test strips to achieve the correct acidity. 
  • And then soak your Rockwool cubes in this new solution for about an hour.

8- Using Rockwool as Growth Medium Might Require Pre Treatment.

Unlike most other media, Rockwool needs to be treated before you can use it for hydroponics. Ensure you soak it in pH-treated water before transferring your plants into it for about an entire day

It might not be a big concern for everyone; it just means that Rockwool is a bit more labor-intensive than other hydroponics media.

Propagation (stem cutting) Using Rockwool Growing Medium

  • Water the mother plant thoroughly, the night before taking the stem cutting, 
  • Remove a 4 inch (10 cm.) cutting from the mother plant; in the morning.
  • Dip the cut end of the stem in honey or rooting hormone and place them in the Rockwool. 
  • Water your plants using hydroponic nutrient solutions.

Let’s have a small comparison between their unique and contrasting features.

What Are The Differences Between Oasis Cubes and Rockwool?

The table below shows the differences between oasis cubes and Rockwool in terms of cost, durability, and pH level.

Oasis cubesRockwool
DefinitionOasis cubes are manufactured from water-absorbent phenolic foam and are generally used for rapid germination of crops.Rockwool is a porous, non-degradable growing medium formed primarily of granite and limestone, superheated and melted, then spun into tiny threads and formed into blocks, cubes, sheets, slabs, or flocking.
DurabilityHas shorter durability. Oasis cubes do not crumble or break apart when cut. Rockwool is a renewable, reliable, and long-lasting growth medium.
Price Low pricedMedium priced
Commercial preparationAvailable in small packs and large bricks for commercial preparations.Rockwool is available in small cubes and slaps for commercial hydroponics.
pHHave a neutral pHHas a basic pH (between 7 to 14)
FunctionsOasis cubes are a growing medium designed for seeds and cuttings and are mostly used for plant propagation.Rockwool is generally used as a starting medium for seeds, rooting medium for cuttings, and large crops, such as tomatoes.
Precautions Beyond seed germination and propagation, Oasis cubes generally have limited usage.
– Also, the foam can break off and clog pump hydroponics system filters.
Rockwool requires continuous pH adjustment to more suitable levels between 5.5 to 6.0.
Table compares oasis cubes vs Rockwool in terms of cost, durability, and pH level – plantsheaven.com

Which Is a Better Medium For Growth: Oasis cubes vs Rockwool?

Each of the persons working in hydroponics will have his own experience regarding the use of oasis and Rockwool. The most important factors for the use of these two growing media include the following:

1- Size of Hydroponics System

In case, if you are growing a small hydroponic garden, oasis cubes are better than Rockwool. Because oasis cubes are available in a number of sizes and shapes. They are far better to use.

Rockwool is made from volcanic rocks that are heated and melted into small fibers. Oasis cubes are made from natural materials like cotton.

If a long-lasting and durable hydroponic garden is grown, then the use of Rockwool is preferred. Rockwool has a longer duration of action than the oasis cubes.

2- Types Of Hydroponics Systems

Oasis cubes are best for water-based nutrient hydroponic gardening. They are a perfect start for beginners as they can be reused and are inexpensive.

Rockwool is the best culture medium for the soil-less mix or the ebb and flow system of hydroponics. They are preferred because Rockwool is known for holding moisture way better than ice cubes.

3- Objects For Growth

Oasis cubes and Rockwool can either be used for some of the varieties of plants. But some plants have specificities, which means they either need oasis cubes or Rockwool. 

Plants grown in Rockwool need more water than those growing in the oasis cubes. However, beginners need to use oasis cubes as they are easy to handle.

4- Climate Of The Area 

The Climate or environment of the agricultural area greatly affects the choice of medium for hydroponics.

Rockwool is the better choice for hydroponics in hot and dry climates because it is helpful in preventing the loss of water.

Oasis cubes are a better choice in cold climates because they serve in keeping the roots of plants quite warm. 

5- Requirements For Water

Rockwool is known for holding the moisture better, so in the more water requiring hydroponics, it is used.

If a plant does not need much water, then oasis cubes are a better option.

6- Budget 

Budget is one of the most frequently considered things when using growing hydroponically.

If you are a beginner looking for a cheaper growing medium, choose oasis cubes as it is cheaper and easier to use. In addition, oasis cube is excellent for fast germination.

Oasis Cubes Vs Rockwool: Which One Should You Choose?

See also: Hydroponics Vs. Soil Gardening: Which One Is Better For You?

Wrapping Up

Hydroponics agriculture requires different growth media of which the oasis cubes and Rockwool are the ones.

Each of these two media has its own pros and cons and the comparison of Oasis Cubes versus Rockwool is really difficult. Depending on the needs of growers, they have different benefits. 


Hello friends, I am Altiné. I am SO excited you are here! I am the guy behind Plantsheaven.com. Plants Heaven is a blog that shares information about preparing, creating, and maintaining gardens in and out of your home, regardless of where you live. My goal is to help you learn to love gardening and reap the benefits that come with it. I am still learning; therefore, the information I share on this site may not always be “expert” advice or information. But, I do my VERY best to make sure the information shared on this blog is both accurate and helpful.

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When growing hydroponically, one of the most critical decisions is choosing a grow medium. Oasis cubes and Rockwool are two great options that have their advantages. But oasis cubes vs Rockwool: which one should you use for your hydroponics? And how do you know which one is suitable for your plants?