First Grow to Hydroponic Hero!

Download the First Grow Cheat Sheet for step-by-step instructions, DIY templates, and shopping lists that will take your first grow to the next level!

By entering your email address you agree to receive emails from Happy Hydro Farm. We'll respect your privacy and you can unsubscribe at any time.

Starting Seeds for Hydroponics + Rapid Rooter Instructions

By: Chris | Last Updated: November 2, 2021

Have trouble starting seeds? Are your plants slow to grow?

In this article, I’ll share my method of starting seeds for hydroponics with Rapid Rooter plugs to increase germination rates, make planting more efficient, and accelerate early-stage root development.

In a hurry? Jump to Rapid Rooter Instructions

What are Rapid Rooter Plugs?

Rapid Rooter starter plugs are an inert mixture of organic compounds that create a great environment for seed germination and early root growth. They can be used for both soil and hydroponic gardening. Since they don’t easily fall apart, they’re a perfect choice for indoor gardeners who don’t want to deal with soil.

What are Rapid Rooters made of?

Sphagnum peat moss and a plant-based foam binder. Good ole natural, organic material without any of the pesky problems that soil brings to the table.

How do Rapid Rooter grow plugs work?

For seed germination, the plugs work as a moisture-holding medium that provides water to the germinating seed. Once the seed has sprouted, the plug acts as both a source of moisture and a supporting media. As a rooting media, the plug provides stability to the plant as the roots develop in and through the soft, airy organic material.

Oxygen is a vital component of overall plant health. It may be hard to wrap your head around, but good soil is rich in oxygen. Most hydroponic systems introduce oxygen at the root zone as well. That’s why so many systems use bubblers. Since water is stagnant in Kratky systems, plants actually develop special “air roots” to absorb oxygen.

The point is oxygen is important. Rapid Rooters work by creating a unique air to water ratio that helps young seeds germinate faster, and develop extensive root systems.

Rapid Rooter Growing Medium - 50 Plugs
$17.99
    Buy On Amazon
    As an Amazon Associate, we earn from qualifying purchases at no cost to you.
    11/27/2021 01:41 pm GMT

    Are Rapid Rooters good for hydroponic gardening?

    Yes, Rapid Rooters are great for hydroponic gardening. The plugs are soilless and were originally designed by General Hydroponics with, you guessed it, hydroponic systems in mind.

    Beyond that, they’re one of the easiest seed starting mediums you can use. They don’t need to be pH adjusted before use like rockwool and some brands of coco coir fibers. The plugs hold water well, but also allow high levels of airflow which reduces the chance of root rot and other diseases.

    Do Rapid Rooters have nutrients?

    No, Rapid Rooters do not have nutrients already in them. They are chemically inert. There is a small chance that minimal amounts of trace minerals may exist in the plugs, but not enough to be either beneficial or harmful.

    Basic Supplies for Hydroponic Germination with Rapid Rooters

    Hydroponic Germination Supplies

    No matter what germination method you use, there are some basic supplies you’ll need for successful germination.

    Tray & Insert
    Since no soil is involved in hydroponic germination, the seed tray serves as a water reservoir. The insert holds the plugs vertical, so they’re not falling over sideways into the water.

    Humidity Dome
    Humidity is key to seed germination.

    60 Cell Seed Starter Kit
    $40.99

    This is a really good deal that includes: (2) Trays, (2) Inserts, (2) Humidity Domes, and (2) Heat Mats.

    Buy on Amazon
    As an Amazon Associate, we earn from qualifying purchases at no cost to you.
    11/27/2021 02:55 pm GMT

    Heat Mat
    Some seeds benefit from the additional warmth provided by a heating mat.

    Grow Light
    Unless you have a sunny windowsill, you’re going to need a light source. Fluorescent grow lights are an affordable and effective way to promote growth.

    Seeds
    If you’re gonna grow plants, you’re gonna need seeds.

    How to Use Rapid Rooter Plugs with Seeds

    1. Soak the plugs in water or weak nutrient solution. Rapid Rooter plugs are spongy and will wick up a lot of water to supercharge germination and early-stage growth.
    2. Add about half an inch of water (or nutrient solution) to the bottom of the seed tray.
    3. Plant seeds. Drop 1 or 2 seeds in the hole on the top of the plug. A small pair of tweezers makes inserting the seeds easier.
    4. Place planted seed plugs into the tray insert.
    5. Cover with a humidity dome.
    6. Place under a low-output grow light. I use fluorescents for seeds/seedlings.

    Tip: Getting algae growth on top of Rapid Rooter grow plugs?
    Overwatering is the most likely cause. Grow plugs shouldn’t stay submerged in water. They also shouldn’t be top-watered. Only the bottom of the plug should contact the water.

    Planting seeds in Rapid Rooter plug with tweezers
    Grow Perfect Salad Greens!

    Download the First Grow Cheat Sheet for step-by-step instructions, DIY templates, and shopping lists that will take your first grow to the next level!

    By entering your email address you agree to receive emails from Happy Hydro Farm. We'll respect your privacy and you can unsubscribe at any time.

    How to Clone with Clonex and Rapid Rooter Plugs

    Cloning, or rooting cuttings, is pretty straightforward with grow plugs. Some plants clone better in aeroponic systems, but I’ve successfully rooted tomato, cilantro, oregano, basil, and many other cuttings in grow plugs.

    1. Soak the plugs in weak nutrient solution.
    2. At a 45-degree angle, take a cutting that contains at least one leaf node, & 3 inches of stem below the leaf node.
    3. Coat, or dip, the freshly cut end of the cutting in Clonex.
    4. Place the cutting into the wet grow plug. Be careful sliding the cutting into the hole in the plug.
    5. Put the plug into a bottom watered tray insert.
    6. Cover with a humidity dome.
    7. Place under a low-intensity grow light until roots begin to emerge.
    HydroDynamics Clonex Rooting Gel, 100 ml
    $19.32
      Buy on Amazon
      As an Amazon Associate, we earn from qualifying purchases at no cost to you.
      11/27/2021 03:16 pm GMT

      Preparing Nutrient Solution for Seedlings

      I say this all the time, but it’s worth repeating. If you plan to use a weak nutrient solution for seed plugs, make sure you use distilled or reverse osmosis water. Most tap or well water contains a lot of trace minerals. Those minerals increase the overall electrical conductivity of the solution.

      What does this mean? For one, it means you’re limited on how many nutrients you can add to the water. Second, those trace minerals can cause a nutrient lockout making your added nutrients less effective.

      Transplanting Rapid Rooter Plugs

      When to transplant will be based on the plant you’re growing. Most plants are ready to transplant 1 week after their first leaves (cotyledons) open. Some plants may need as much as 3 weeks before transplanting to allow time for healthy root development.

      The best indicator that a seedling is ready to transplant is when roots start emerging from the sides or bottom of the plug.

      Normally, a plant is ready to transplant into a hydroponic system once it has formed its first “true” leaves. True leaves are the sets of leaves that develop after the initial seed leaves. These seed leaves are called cotyledons.

      Grow plugs can be transplanted into any growing medium whether it be a hydroponic system or soil.

      If you start seeds in net pots, be aware that roots will form around the mesh of the net pot. Don’t let the seedling develop too many roots before transplanting to avoid root damage.

      Storing Unused Rapid Rooter Plugs

      I don’t understand why they do this, but General Hydroponics staples the label onto Rapid Rooter bags. The staples render the “resealable” bag useless after opening. To safely store unused plugs after opening, move them to a large sealable plastic bag.

      The sealed bag will help prevent the grow plugs from drying out. Store the bag in a cupboard or drawer where it won’t receive direct sunlight. If you notice the plugs seeming a little dry, add a teaspoon of distilled water to the bag and reseal it.

      Common Questions About Rapid Rooter Starter Plugs

      You’ve got questions, I’ve got answers. Below are the most common questions I get from hydroponic gardeners using grow plugs for the first time. Have a question I didn’t answer? Contact me!

      How Long Should I Soak Rapid Rooters?

      Long enough to saturate the plug with water. I hold the plugs underwater for 30 seconds to one minute.

      They’re basically a sponge. Once they’re saturated with water, they don’t get wetter.

      There are some crazy recommendations out there when it comes to soaking time, but let’s think about this rationally. What is being accomplished by soaking for hours, or even longer? Nothing.

      Do Rapid Rooters Go Bad?

      Yes, they can go bad. The most common way they go bad is by drying out. It’s no worry if they become a little dry, but if they reach the point where they are hard and brittle you may as well throw them away.

      Also, if the storage bag is too wet it becomes a breeding ground for mold, algae, and different types of bacteria. This unwanted growth is accelerated if the plugs are not stored in a dark place.

      Only soak plugs if you plan on using them immediately. Soaked plugs should not be stored with other plugs.

      Can Rapid Rooters be Rehydrated?

      As long as they’re not completely dried out, Rapid Rooter plugs can easily be rehydrated before use by soaking them in water, or a weak nutrient solution.

      If the plugs are totally bone dry, they will feel brittle. If your plugs have reached this point, there’s not much you can do to salvage them.

      How Long to Leave Seedlings in Rapid Rooter Plugs?

      Short answer, forever. Rapid Rooter starter plugs are designed to support a plant throughout its entire life cycle. So, you keep seedlings in the starter plugs for the entire life of the plant.

      The plugs can be transplanted into soil or hydroponic systems.

      Are Rapid Rooters Organic?

      Rapid Rooter starter plugs are made from organic, natural materials. While they are made from organic material, they are not Organic Materials Review Institute (OMRI) listed. With that said, these plugs are perfect for hobbyist organic gardeners.

      How Big are Rapid Rooter Plugs?

      Rapid Rooter Plug Size

      Roughly 2 inches tall, and 1 ½ inch around at the top, with a 1 ¼ inch base.

      They will fit in a regular 72 cell seedling tray insert. These trays are easy to find at garden stores, big box stores, and online.

      They will also fit in the larger 36 cell seedling tray inserts. All you really need is an insert that will keep the plugs from falling over.

      Are Rapid Rooter Cubes the Same as Plugs?

      Yes, cubes and plugs are similar terminologies that both refer to the same product.

      Chris Cook started Happy Hydro Farm to share his passion for hydroponic gardening! Growing your own food is incredibly rewarding both physically and mentally. His mantra - "Take excellent care of your plants, and your plants will take excellent care of you."
      Grow Perfect Salad Greens!

      Download the First Grow Cheat Sheet for step-by-step instructions, DIY templates, and shopping lists that will take your first grow to the next level!

      By entering your email address you agree to receive emails from Happy Hydro Farm. We'll respect your privacy and you can unsubscribe at any time.