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Growstones – Better results with Hydroponic Substrates and Aggregates

Growstones Aggregates: A Hydroponic Medium for Better Cannabis Growing

Growstone Hydroponic Substrate You’ve put in all the time, effort and cash to create your ideal hydroponic grow set-up. You’ve chosen the best grow lights, arranged the space to accommodate new seedlings, clones, vegging and flowering plants. After all that work, don’t settle for an inferior hydroponic growing medium. For the highest yields of frosted buds you need a medium that holds the perfect balance of water and air. Sure, you could purchase and carefully mix perlite, coco coir and hydroton. Or you could simply open a bag of Growstones Hydro Stones, soak them overnight, and start growing. Young Cannabis In Growstones

What are Growstones?

Made entirely from recycled glass, Growstones are as ecologically friendly as they are functional. These are small, irregularly shaped, heavily pocked stones. They are light-weight, dust free and suitable for nearly any hydroponic set-up. Growstones are unique among hydroponic mediums in that they hold nearly equal amounts of air and water at saturation (after all free water has drained away). Plant roots require at least 20% air for optimum root development and growth, and levels up to 45% are even better. Take a look at the chart below comparing air and water holding capacity of the two Growstones products to other commonly used hydroponic mediums. Growstone Hydroponic Cannabis Medium Comparison

Why Choose Growstones?

Growstones have many qualities that make them the ideal hydroponic medium for your next indoor grow.


  • Hold three times more water and 12% more air than Hydroton
  • Are fully reuseable
  • Are lightweight
  • Are a sustainable and eco-friendly growing choice
  • Are completely free of weed seeds or mold spore

Growstones provide superior:

1. Aeration and drainage

The pores in each irregular Growstone have special features to improve root health and plant growth: they are of variable sizes and interconnected. The large pores allows for fast air and water exchanges, so that oxygen dissolves quickly, while the little pores develop a coating of the oxygen rich water to supply the roots. The interconnected pores offer a large surface area in for root growth.

2. Capillary Action

Growstones aggregates have some serious wicking ability. They can pull moisture up to 15 cm above the water line. This keeps the roots evenly moist, and means you need less water in an Ebb and Flow or Continuous Flow set-up. Growstones Marijuana Ebb and Flow

3. High Steerability

Because Growstones tend to be drier than other hydroponic mediums, it is easy to make changes to your nutrient levels and ratios. This facilitates an easy transition from vegging to flowering nutrients.

4. Silica Release

Being made of glass, Growstones release a small amount of silica in a form that is accessible to plants. Silica has been shown to improve a plant’s resistance to rot, pests and disease. While we’re not sure Growstones release enough of this useful mineral to make a difference, it is a side benefit that might help and definitely won’t harm your grow.

5. Low Risk of Rot

The dryness of Growstones means you can feed your plants more frequently, giving them an extra boost of nutrients without running the risk of waterlogging them or creating root rot.

6. Multiple Use Options

While Growstones make an ideal hydroponic medium, they are also a good addition to a soil mix. The stones can be added to any soil to provide increased aeration that will boost plant health and reduce the risk of root rot or overwatering. Growstone Coco Mix for Healthy Harvest

Features of Growstones

Here are the nitty gritty specs for those of you interested in the technical details.
Physical Characteristics of Growstones
Electrical Conductivity (mmho/cm)
Total Porosity (v/v)
Water Holding Capacity (v/v)
Air Filled Pores (v/v)
Bulk Density (g/cm3)
You can purchase Growstones in three sizes, each with a particular application.
  1. Small (2 mm) – Ideal for propagation mixes
  2. Medium (5-12 mm) – For aeration in soil mix
  3. Large (12-25 mm) – Best for most hydroponic systems

What Growers are Saying

People love this product. Indoor gardeners working with tomatoes, coffee and other vegetables are chucking their lava rocks, coco coir and Hydroton in favor of this lightweight, non-toxic and undeniably functional medium. It is time for cannabis cultivators to get on board and give Growstones a try. Tomato growers claim the aggregates offer a lot of support to heavy plants and require less staking and caging. The same should hold true for your marijuana girls as they develop their hefty harvest. If you have used Growstones please tell us about your experience in the comments below. Get a Great Cannabis Harvest

A few words of caution

No product is perfect, and Growstones two mediums are no exception. Here are the potential drawbacks:
  • Rinse Well and Carefully
    • Growstones come coated with a fine dust of silica. This needs to be carefully washed off. This is best done outdoors or in a well ventilated space. The dust is not only hard on drains, but it is dangerous to inhale.
  • Keep an eye on pH levels
    • Growstones use calcium carbonate as a foaming agent. In some set-ups, particularly in aquaponics systems which rely on a symbiotic relationship between fish and plants, this can cause pH levels to rise. Be sure to check your pH frequently and make adjustments as necessary
Be sure to soak the stones for a full 24 hours before using them. This will balance the pH. Growstones come with thorough instructions, and the owners are very friendly and responsive to queries. Growstones Cannabis Top Drip System


If you are looking for a great growing medium or soil aerator, give Growstones a try. Not only will they make growing healthy plants a breeze, but you’ll be doing your part for the environment. Indoor cannabis cultivation usually leaves a significant carbon footprint. It is somewhat ironic that a plant often associated with Earth-lovers and hippies is now being grown in a way that is not sustainable. Incorporating a renewable, reusable growing medium like Growstones into your set-up is a great first step to making indoor marijuana viable in the long-run.