Hydroponic Substrate

Growstone Hydroponic Substrate
Growstone Hydroponic Substrate is the perfect growing media for herbs, vegetables, fruit, and flowering plants including tomatoes, orchids, strawberries and gerbera daisies. They can be used in hydroponic grow systems as simple as manually irrigated containers, or as advanced as automatically drip irrigated containers, Ebb-Flow systems, and NFT tables.
Growstones Give You:
- Balanced ratio of air/moisture over time for healthy vigorous plants
- Efficient absorption and release of water/nutrition for reduced plant care
- Optimum flexibility for different plant needs for consistent high yield
An Engineered Product for Consistent Results
Growstones media are engineered to provide an effective balance of aeration and moisture characteristics for your hydroponic growing system. Other substrates maximize either air or moisture, but Growstones are designed to allow for both rapid moisture absorption and controlled drainage and oxygenation.
Recycled and Recyclable
Growstones are manufactured using up to 98% waste materials. They replace strip-mined materials like pumice, perlite, and stonewool, reducing environmental degradation. At the same time, since the product largely consists of recycled bottles, a large amount of waste is given a new life, keeping it from the landfill.
Growstones are a reusable plant-rowing medium. To recycle, Growstones can be sterilized and used again or simply added to soil to improve texture, structure, and aeration.
Growstones are the Perfect Growing Medium:
- Holds an even ratio of air to water
- Is easily flushed and re-wets easily after being completely dehydrated
- Is reusable
- Sterile, no weed seeds or disease spores
- Is lightweight and easy to work with both indoors and out
- Made in the USA
- A sustainable and earth-friendly option
Download Technical Data for Hydroponic Substrate
Getting Started

When you grow hydroponically, your roots need a stable and well-drained foundation for maximum stability and growth. Growstones provide that perfect foundation as a highly porous, non-compacting, and non-clogging substrate, which enhances gas exchanges between roots and the atmosphere. Roots will grow healthy and ready to take full advantage of the dissolved nutrients.
Directions
At home or in the greenhouse, Growstones are an ideal substance to grow a wide variety of crops in different hydroponic systems. Growstones can be used in systems as simple as manually irrigated containers, or as advanced as automatically irrigated systems such as drip irrigated containers, Ebb-Flow, and NFT tables. For best plant performance, follow these simple steps and recommendations:
1. For first time use, rinse by submerging Growstones in a bucket of water.
2. Volume of water should be approximately five times the volume of Growstones. Add a pH adjusting solution (pH down) to reduce the pH of the rinse water to 5.5 – 6.5. For best results let soak for one hour.
3. Discard rinse water.
Seeding and Transplanting
4. Place rinsed Growstones in your growing system.
Ebb-flow systems
Fill container with a volume of Growstones proportional to your recirculating pump. Nutrient solution should rise until Growstones feel moist to touch 1” to 2” below the surface.
NFT systems
Total depth of Growstones should be adequate to support and keep root crown above water level or flow.
Containers
Fill container with Growstones to within 1” from the top.
5. For direct seeding place seed in a peat or other soilless mix plug and insert plug into Growstones media.
6. To transplant seedlings, gently insert bottom of plug with seedling into the Growstones media.
Build a Hydroponics System with Growstones
pH and Nutrition
Most plants perform best when pH of nutrient solution is between 5.5 and 6.5. Please consult your local garden center or hydroponic store for more information on pH adjusting solutions as well as nutrient formulations that will most benefit your plants. If your local tap water is hard, the use of reverse osmosis water is recommended.
Most pre-mixed formulations developed for greenhouse or garden plants will need Mg and Ca supplementation.
NFT systems
Maintain thin film of nutrients flowing at all times.
Containers
For recently transplanted seedlings, irrigate once to twice a day. As plants grow, maintain moisture 1” to 2” below surface. Irrigate until drainage is visible from bottom of container enough to maintain surface of Growstones moist to touch.
Manual Irrigation
Manual irrigation in Growstones is generally recommended for low water usage plants such as aromatic herbs, perennials or short cycle vegetable plants grown in individual containers.
Frequency and Duration
Twice a day until bottom drainage is visible. As plants grow, increase irrigation frequency to maintain surface of Growstones moist to touch.
How To Reuse Growstones
To reuse Growstones in a second crop, simply remove old plant material from the container and shake well to displace any Growstones attached to roots. As with any media, it is desirable to sterilize the previously used Growstones to eliminate any pest or disease that may be present before reusing the Growstones in another crop. Growstones can be steam sterilized without loosing physical integrity, or more simply they can be rinsed with a 10% diluted bleach solution. For directions on seeding and transplant, simply repeat steps 5 and 6.