How Often to Water Rockwool Seedlings

Rockwool Watering Schedule - How Often to Water Rockwool Seedlings

We already have numerous ways of farming methods to give us more options with regards to farming. Every farming method offers us a kind of satisfaction, whether small or large scale farming.

One method that is popular among commercial farming, especially hydroponics, is Rockwool. It became popular throughout the farming industry because of its remarkable advantages. It can accommodate many plants that growers have, which makes Rockwool quite reputable when it comes to farming.

In this article, we will discuss how it works to get a better understanding of the nature of Rockwool to give us a clear insight into how to use it. Also, the watering cycle of Rockwool needs to be properly elaborated in precise details. This article aims to offer every aspiring grower to expand their horizons by including Rockwool in their field of expertise.

How do Rockwool Seedlings Work?

Perhaps the first thing we need to know is how it works and the properties of Rockwool that make it an almost perfect medium for seeds to grow.

Rockwool came from basalt rock and chalk, which was exposed to high temperature while spinning continuously until it reached the fibrous appearance. It is then compressed into a mat-like form and cut into cubes ready for indoor farming.

Additionally, the process of compressing the Rockwool comes in different ways to fit the demands of every grower concerning their crops. This is because the Rockwool density determines the properties such as the moisture-holding capacity, aeration, and moisture gradient. This is one of Rockwool products’ unique characteristics, which allows growers to choose the type of Rockwool that fits the demands of their crops to maximize profit.

Therefore, all these features present in the Rockwool product make it a safe environment for seeds to grow. Sometimes, it is stressful for some growers to start seeds to grow because it is quite delicate to handle and requires excellent moisture accuracy to promote germinationOpens in a new tab.. Too much moisture in the seeds will lead to death of seeds.

Thankfully, Rockwool products help the seeds thrive because of their capacity for moisture retention. Rockwool cubes help the seeds from dying because they do not clog the seeds with too much water. The seeds only need enough water to activate enzymatic reactions that trigger germination, which most Rockwool products can do.

Another factor contributing to the Rockwool products being an appropriate medium to grow seeds is its sterile state. The process that Rockwool products have to go through before it turns into a planting medium paves the way for the product to be sterile.

This soilless growing medium’s sterile quality allows more safe space for the seeds to develop compared to using soil where the microbial population is already present before planting the seeds.

It is important to remember this excellent process between Rockwool products and seeds. After this, we will proceed to the watering schedule of Rockwool seedlings.

Rockwool Watering Schedule

When watering Rockwool seedlings, it is crucial to know Rockwool products’ characteristics, especially the moisture-holding capacity. Standard Rockwool products usually contain 80% nutrient solution, 15% aeration space, and 5% Rockwool fibers after it has been drained freely in irrigation.

However, these measurements differ from one Rockwool product to another, depending on the brands.

The correct time to water Rockwool products is when it is barely moist or already dried out. Rockwool seedlings need to be watered once a day in Vegetative Growth Stage and twice a day in the Blooming Stage.

However, do not irrigate the Rockwool products when there is still enough moisture in the material to prevent overwatering the plant roots.

Rockwool watering schedule is quite different from other growing mediums because of its characteristics and how the material is manufactured.

It is important to remember that Rockwool products are fibrous and designed to strictly follow the right moisture content. For this reason, the irrigation of Rockwool products should remain a short but constant nutrient solution application enough to reach field capacity.

The term “field capacity” refers to the process of Rockwool irrigation where, after irrigation, the material has drained fully but leaves enough moisture content to nourish the plant roots until the next irrigation.

It is vital to allow the Rockwool products to drain excess water to avoid clogging the plant roots while enough moisture is retained for the plants to grow.

Also, the moisture gradient of Rockwool products between top and bottom is another thing to notice. We might see that the upper layers of Rockwool products appear to be dry; hence we are compelled to think it needs water. But, you are wrong because the bottom layers of the Rockwool products are saturated with plenty of moisture.

It will become a problem when growers do not know about this unique characteristic of Rockwool products, and there will be higher tendencies of over-irrigating them.

The dryness on Rockwool products’ surface area allows access to an abundant supply of air and oxygen for root respiration. The moisture at the bottom contains all the nutrient solutions bringing essential elements to the root system.

This moisture gradient from top to bottom provides the plants to extract water for growth at a very low moisture pressure in the Rockwool. Another thing to observe is when Rockwool products drain 70-80% of their moisture content; it does not cause severe wilting to the growing seeds because of their moisture-holding capacity.

This gives the advantage of Rockwool products to starting seeds compared to other growing mediums.

Dos and Don’ts of Rockwool for Plants

Despite Rockwool products’ pretty characteristics in the farming industry, growers need to pay special attention and consideration when working with them. At the same time, it may be true that they are proven to be productive in terms of growing seeds, some drawbacks of Rockwool products needed to be.

The dos of Rockwool products:

It would be best if you correctly prepared the Rockwool cubes before putting seeds on them. This will get rid of their natural pH, which is considerably high for most plants to handle.
Wear protective gear like gloves, eye protection, and masks when handling Rockwool products. These materials are very fibrous which are infuriating to the skin, eyes, and lungs. Protective gears like masks will keep you from inhaling the fibers and eye protection to the fibers getting contact with your eyes. You might want to wear gloves and long sleeves shirts to avoid the fibers from reaching your skin. It is imperative to protect yourself all the time.
Sterilize the feeding solution before putting it back in the Rockwool products. There is still a tendency that it might be prone to algae and bacterial growth, which might lead to contamination.
Please dispose of the Rockwool materials properly after using them. Throwing them is not the best idea to make because they will not break down immediately. The convenient way of disposing of them is by breaking them into pieces and combining them in your garden or potting soil to increase their moisture capacity.
Heat treat the Rockwool products if you are planning to reuse them. Heat treating them includes steaming or pouring hot water on them or putting chemical solutions to sterilize the materials and rinse them thoroughly. This is to safeguard the Rockwool products from any bacteria or fungus living in them after their previous use.

The DON’TS of Rockwool products:

Squeezing the cubes when they are wet destroys the internal structure that the Rockwool products are known for. If you want to remove some water in them, you might as well leave them to dry excess water all by themselves, or you could lend a helping hand by shaking them gently.
This way, you can help them in their draining process without destroying their natural composition.
Forgetting that the Rockwool products are inert. This means that they cannot provide nutritional value to the plant roots growing in the cubes despite having good water retention. They need to be supplied with nutrients, which are vital elements for the plants to grow.
Using the Rockwool products out of the package. It is essential to soak them in water until no more air bubbles are coming out of the water before growing seeds on the materials. Rockwool products from packages are completely dry and might suck off the plants’ moisture if you use it directly out of the package without soaking them wet.

Steps on How to Plant Seeds in Rockwool

You can grow different types of seedlings in Rockwool products. Whether you are planning to grow leafy vegetables, herbs, or bigger vegetables, Rockwool can handle them.

Now, the next thing you need to know is how to plant them in the Rockwool successfully. Do not worry because there are details to help you with that.

Here are the steps on how to plant seeds in Rockwool products:

1. Prepare the Rockwool products. You must soak all the cubes and adjust the pH level to 5.5 up to 6.5.

2. Insert two seeds in the hole located at the top of the plug. You can use materials like a toothpick to push the seeds downward until it reaches the bottom of the hole.

3. Close the hole by pinching the top of Rockwool. You can also add a small piece of Rockwool to the hole if pinching does not work.

4.Put them in a try and keep them in a place where the temperature is around 70-80 degrees Fahrenheit.

5.Check them every other day to make sure that the cubes are not drying out. If they did, you can add a small amount of water but see that you do not overwater them because the bottom part of it still contains water even if the top layers are dry.

6. Place them under the growing lights once the seeds are starting to sprout.

7. If you see a dominant seedling, do not remove the smaller shoot as it can damage the shoots of larger seedlings. It is better to trim the shoot of smaller ones.

8. You can transfer the seeds once they reach two or three inches in height. There is no need to remove them from the plug since it is safe to transplant them to the other growing medium.

Advantages and Disadvantages of Rockwool Seedlings

While there are many positive comments regarding the effectiveness of Rockwool, we might still want to know its advantages and disadvantages completely. This helps us have total control when working with them. Nothing works better than knowing everything you’re working with.

Here are some advantages of Rockwool:

Sterile and Inert due to manufacturing process.
Do not decompose over time.
Maintains physical properties over time.
Maintains ideal levels of aeration.
Lightweight and easy to handle.
Remarkable water retention.
Lesser water consumption.
It prevents root suffocation and overwatering.

Here are some disadvantages of Rockwool:

Bulky in size before cutting into cubes, making it difficult to transport.
Needs a fully leveled surface to even moisture gradient inside the material.
Disposal may require some extra effort compared to other growing mediums.
Fibers of Rockwool are harmful to a human when working without protective gear.
Additional expenses due to protective gear.
Requires precision in terms of irrigation.
Since it is inert, it relies significantly on nutrient solutions supplied to them compared to coco, which has specific potassium levels in them.

Final Thoughts

You can never go wrong when it comes to using Rockwool for seedlings to grow. It is efficient and reliable, although not suited to every type of farmer. Rockwool requires special care and demands strict compliance in terms of irrigation.

If you are a small-scale farmer on a tight budget, Rockwool may not be suited for you. But if you are eager to get a hold of it thinking it fits your preference, you might as well go for it because no one is stopping you. Just remember every detail about Rockwool products as you need them once you start using them.

Jenny M
Tribal Writer

Edited by:
Patricia Godwin


Patricia Godwin

Patricia has many years of experience as a content writer on various subjects, but her first love is gardening. She’s never met a plant she didn’t like and, consequently, she writes about every type of plant you can think of. Once an avid gardener with a herb garden, a succulent rockery, and a rose garden – to mention a few. Nowadays, she’s constantly on the move searching for interesting plants to bring to your attention; and explain to you all the details you need to grow, care and maintain these plants.

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