Category Archives: Sustainability

Why You Want to Kiss Clay Pebbles Goodbye

Clay pebbles available today

Growers have had a love hate relationship with clay pebbles for years. Now there’s finally a choice. Besides the clear advantage of providing a higher level of aeration than clay pebbles, Growstones have significantly less fines, and release silica over time in a form plant roots can uptake.

Here are some of the advantages of Growstones aggregates over clay pebbles based on actual physical characteristics of both substrates.

1. Higher air-filled porosity

At field capacity (i.e. after irrigation water has drained away), clay pebbles air-filled porosity is about 42%, while Growstones hydroponic media is 48% by volume. This corresponds to at least 12% higher aeration in Growstones than clay pebbles. The importance of high porosity in hydroponic growing cannot be undermined. Ideal substrates have small and large pore spaces. When the substrate is irrigated, water is held in the small pores but quickly drains through the large pores, allowing fresh air to flow through the soil, bringing oxygen to the roots and removing carbon dioxide from the root zone.

The Importance of Buffered Coco and Why We Use It in GS-3 Coco Mix

As I am sure you know, coco peat or coco coir are byproducts of industries that use coconuts. Coconut tree plantations are found in the tropical and subtropical areas of West Africa, Asia, South America and Central America. Garden grade coco coir is created by a series of steps like aging, washing, rinsing, drying, buffering, grinding, and grading. Without proper processing, coco coir will have an excessive salt content, degenerate and compact resulting in problems with Pythium root rot, and lead to nutritional imbalances especially related to calcium and magnesium deficiencies.    

Without going into too much chemistry, we'll explain cation exchange and coco coir. Since coco coir has a negative charge, it can hold certain nutrients and keep them from the plant (nutrient lockup = BAD). Suppose you are growing a fast growth annual flowering plant. You want every bit of calcium to get utilized by your plant. Nutrient lock up will affect plant health and reduce overall yields. 

So, how do we make sure our coco coir doesn't contain a lot of elements that will lock up expensive fertilizers, burn plants with excessive unwanted salts, and reduce plant health and yields?

The Science Behind Gnat Nix for Fungus Gnat Control

gnatnix-illustrationDid you know that potted soil from garden centers often is contaminated with eggs and/or larvae of fungus gnats? That means before you even start, you could have a fungus gnat problem and not even know it. Whatever the source of your fungus gnats issue, larvae are the source of plant damage. They feed on algae, fungi, decomposing organic matter, and plant roots in the growing medium. They prefer feeder roots and root hairs, both of which are important for plant health and vigor. If these roots are damaged plants may lose vigor, wilt, have poor growth, leaves may turn yellow and drop.

What’s more, even though adult fungus gnats don’t bite or feed, as long as they are able to complete their life cycle, there will always be potential for plant damage from larvae. Up until now, there was no way to significantly disrupt a gnat’s life cycle without the use of chemicals.

Not any more.

Time Is Money! GS-3 Saves You Both


Time to a grower is crucial. Why waste it measuring, blending, and preparing your blend? Did you add enough? Did everything get evenly mixed? Without the proper blending equipment, it’s a guessing game. Inevitably, you will have that ½ bag of something left over taking up space. All of this can be a waste of your time, which ultimately is a waste of your money. Not anymore.

We’ve done all the work for you!

Growstones hit the roof with Rooftop farming in Brooklyn

Edenworks family

This is a guest blog by Jason Green of Edenworks. Growstone is collaborating with this Brooklyn-based startup helping to build the future of urban farming. 

Presently, cities are largely hubs of consumption, but there’s a growing tide that is instead moving cities toward becoming closed and renewable ecosystems. Much of the driving force behind this change is increasingly conscientious consumers demanding locally and sustainably grown food. But a gap exists between the availability of this local produce, especially in cities, and the ever-increasing demand.

Some technologies, like hydroponics and aquaponics, offer a glimmer of hope for solving this problem. However, large scale systems are expensive to build, require significant expertise to operate, and are further constrained by the uniquely cramped and vertical environment of cities.

Our Fix on Chow Mix

 Coco mix plant shotGS-3 Coco Mix

Growstone’s new revolutionary take on the “chow mix”

What is a chow mix? Chow mix started a few years ago when a handful of growers mixed expanded clay pebbles (Hydroton at the time) with coco fiber creating a soilless growing medium. The addition of the clay pebbles allowed their mix to drain faster. As with any fast draining growing media, the grower can increase the number of feedings per day without the risk of over watering. These frequent feedings provide an opportunity to exchange the stale air and spent nutrients in the plant’s roots. In this situation more feedings = bigger yields!

Fast growth flowering plants enjoy a rapid draining root zone. Essential oil production and flower density increase with a “steerable” root zone. Any experienced grower knows a simulated drought at strategic periods during a plant’s life can trigger changes in growth increasing yield, potency, flavor, and aroma. Chow mixes are ideal for this style of gardening!

Gnat Nix VS Diatomaceous earth. The Results are In!

Gnat Nix!

Are you using diatomaceous earth or sand in an attempt to control fungus gnats but still see them flying around?

Know why? They don't work.

According to Kansas State University, Diatomaceous Earth and Sand are NOT effective control for Fungus Gnats? (Source: Raymond A. Cloyd, Fungus Gnat Management on Greenhouse-Grown Crops, Kansas State University, September 2010).

It has been thought that fungus gnats are more of a nuisance than harm. However, that annoying cloud of gnats can do way worse damage than getting stuck in things you wish they wouldn’t.

Fungus gnats lay their young in the top few inches of soil. These larvae feed on your roots reducing root mass. Less roots = less yield! Even worse, recent evidence has shown they can carry harmful spores leading to certain fungal infections. The open wounds created by the feeding larvae are an entry point for these plant pathogens.

Growstone’s Favorite Things Recycled… and Rethought

p>recycle-glass-with-ecyclerWhy do you love Growstone? It probably has something to do with our supreme aeration abilities, the fact that our aggregates are non-toxic and chemical free, and even better, we continually outperform all the other growing mediums on the market.

The other side of Growstone is also our sustainability story. We make no secret about it – our manufacturing plant is located in the middle of a landfill. We take trash (in this case, discarded glass bottles) and turn it into growing treasure. 

Growstone has rethought how to approach growing mediums. Unlike perlite or diatomaceous earth, our products are not the results of strip mines. We appreciate other companies and products that originate from recycled materials, and here are some our favorites:

Growstones, Coco Coir and Redwood Fiber: So Happy Together

Today, more and more growers across the country are finding real benefits in using soilless mixes which combine high quality media with complementary physical characteristics. We agree.

Growstone designed an amazingly balanced, ready to use and sustainable and environmentally-conscious blend, GS-3 Coco Mix.

GS-3 coco mix combines the high porosity of Growstones with the great water holding capacity and biological benefits of high quality buffered coco coir and redwood fiber, topped with a high concentration of Mycorrhizae. The mix was also designed with ideal pH levels in mind.

The synergies created are undeniable.