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Hydrofarm

GROW!T GMC40l - 4mm-16mm Clay Pebbles, Brown, (40 Liter Bag) - Made from 100% Natural Clay, Can be used for Drainage, Decoration, Aquaponics, Hydroponics and Other Gardening Essentials

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Availability: In Stock.
Fulfilled by Amazon
Arrives Wednesday, Aug 5
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Size: 40 Liter Bag


Pattern Name: Bag


Features

  • Extremely stable in both pH and EC
  • Made from 100% natural clay
  • Pre-washed to aid in stability
  • Drain freely and do not hold any excess water, providing good oxygen levels around the root
  • Will not float once fully wet

Description

GROW!T horticultural clay pebbles are made from 100% natural clay. They are clean, pH stable, and offer great aeration and drainage in hydroponics, especially in flood and drain, deep water culture, and drip feed systems. Due to their unique structure and ability to cover a large surface area, they offer the ideal environment to foster beneficial bacterial growth around the root zone, leading to naturally healthier plants.GROW!T Clay Pebbles can be used for:•Aeration of growing media - ideal to mix into coco coir or soil to aid aeration •Drainage - will hold water as well as offering great aeration properties and free draining •Decoration - looks great as a top dressing for pots and also helps to prevent evaporation •Hydroponics/hydroculture - used widely in hydroponic growing, they are ideal for flood and drain, deep water culture and drip feed systems •Aquaponics - are also ideal to be used in aquaponic systems

Brand: Hydrofarm


Style: Classic


Item Weight: 20 Pounds


UPC:


Global Trade Identification Number: 44


Brand Name: Hydrofarm


UPC: 638104013444


Global Trade Identification Number: 44


Unit Count: 40.0 Count


Model Number: GMC40L


Manufacturer Part Number: GMC40L


Manufacturer: PLANT!T


Manufacturer Warranty Description: Warranty.


Included Components: Clay Pebbles


Item Type Name: Clay Pebbles


Style Name: Classic


Item Weight: 20 Pounds


Volume: 40 Liters


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, Aug 5

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Good product
Size: 40 Liter Bag Pattern Name: Bag
Clean and works well
Reviewed in the United States on November 17, 2025 by Jesse Sartin
    • Hydroponic friendly Hydroponic friendly
Size: 40 Liter Bag Pattern Name: Bag
Review Image by John
I've used these and ones like it for a little while now. I've got a hydroponic flood and drain system that's about 5 months old or so. They work as a fantastic base for most plants. They only seem to struggle with large heavier plants like tomatoes. Pictured is some parsley, lettuce, and the shoots you see between the lettuce is ginger we tossed in just to see how it would do. ... show more
Reviewed in the United States on May 20, 2026 Reviewed in the United States on May 20, 2026 by John
    • Good value for starting semi-hydro
Size: 40 Liter Bag Pattern Name: Bag
Starting my semi-hydro plant journey and bought these. They're not like the perfect orange-y colored balls that you see some people using. These are a regular brown color and are more irregularly shaped, but that's fine for me because I had read it's actually easier to situate your plant in the irregular-shaped leca instead of the perfect balls. For the most part these haven't sunk after soaking them in water (even after soaking for weeks), but I don't think that really matters as far as actually using these for planting because none of the plants I've moved to leca have died and it's been a couple months now. ... show more
Reviewed in the United States on April 21, 2025 by CC
    • ANY ?'s I have researched this for you. ANY ?'s I have researched this for you.
Size: 40 Liter Bag Pattern Name: Bag
Review Image by Plant On!(tm)
Review Image by Plant On!(tm)
Ok, while soon many questions regarding this product have surfaced, and there is conflicting data, I have done research. I have DONE SERIOUS NUMBER CRUNCHING FOR EVERYONE, NOT BIASED AND NOT A PAID ENDIRSMENT. While this product will not be suitable for aeroponic use, as it floats more than sinks... It will displace water and will not alter ph. A 40 liter bag is 1.4 cubic feet- the bag will come to. Just about your knees and is about a foot wide. (See photos) Upon rinsing and reweighing after days of dying, I found that 14.3 ounces were lost. Upon a second testing on another bag- twice that was lost, so a great variance is seen upon batches. This product is often hated as of "... So much orange water and rust left behind" after initial rinsing and being held in a 5 liter, 10 liter and 20 liter containers filled 3/4 respectively and equivalent quantity of tap water with a ph of 6.8, with rather high levels of phosphate, though no ammonia, nitrates, nitrites, nor more than a slight reading of chlorine, left for 1 month the following was found: the 5 liter container retained NO discoloration and .7 ounces of "rust" whereas the larger containers in fact, oddly- all results were found after repeated twice, left no orange water and almost no rust. So, the less you use- the more is left behind. This may be due to several reasons. Of which comes down to NOTE: -results are being sent to chemists, an organic biologist and numerous PhDs and waiting to revise with findings on this and a couple other oddities which require determinations from colleagues- In summation, this is a fantastic all around medium which is inexpensive, versatile, and when mixed with a few bags- consistency (obviously) becomes less of a con. I have used other products, I have used every other product available to the public. Findings: while other products may be superior- until their prices come down, expanded clay will be the continued choice for DWC, Gravity fed Dripers, and more advanced timer based drip systems, among other systems including a cheap GREAT way to ensure your soil is constantly well drained and consistently consistent. Any further questions? PLEASE ASK, I have MORE data to come! Thanks for your interest, and time. ... show more
Reviewed in the United States on April 23, 2015 Reviewed in the United States on April 23, 2015 by Plant On!(tm)
    • The best leca product there is, basically an industry standard
Size: 10 liter Pattern Name: Bag
If you require these, you already know what you need them for. The build quality is excellent. They are simple to setup and easy to use. They do an outstanding job of storing and transporting your water & nutrients. These are the golden standard of leca. Absolutely highly recommended.
Reviewed in the United States on May 26, 2025 by Andy
    • Waterfall Waterfall
Review Image by Michael Twitty
Review Image by Michael Twitty
Review Image by Michael Twitty
Hydrofarm clay balls to keep moisture in my snake terranium. A great component for making a waterfall
Reviewed in the United States on March 19, 2026 Reviewed in the United States on March 19, 2026 by Michael Twitty
    • My favorite LECA
I bought this LECA because it was the cheapest I could find for the quantity. As others have mentioned, most of it is not round. If aesthetics are concerning for you, this LECA isn’t for you. I actually think all the variation makes the LECA fit together nicer, and I actually get better results with it. Yes roots stick to it, but roots stick to the round ones too. Yes it’s a little dusty when you get it, but what LECA won’t be? They all rub on each other during shipping. Just rinse it and it’s completely fine. No they do not sink. I don’t know what makes these different than others, but they definitely always float. It doesn’t really bother me, so that’s not a concern. Having said all of that, I’m very happy with it for what it is! It works great and the price is right! ... show more
Reviewed in the United States on June 19, 2020 by Review2Me
    • Solid budget option
Size: 40 Liter Bag Pattern Name: Bag
You get A LOT for what you pay, but I struggle with this brand because they float so easily. Makes it harder to thoroughly clean them, and also makes it hard to water the plants. I find I have to mix in another brand of leca that’s more compact and heavy in order to offset the floating. It’s a solid budget option. I’m still saving a bit by not having to buy as much of the expensive stuff, but not as much as I hoped. ... show more
Reviewed in the United States on December 13, 2025 by dreamer194

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