Do-it-yourself (DIY) hydroponic gardening is a rewarding,
pleasurable pastime. To this end, designing your
own setup (as opposed to buying a kit) saves money on
supplies while also teaching many the nuances of hydro
growing. As many DIY gardeners know, the design process
consists largely of weighing your options on equipment
and assessing your buying choices.
While hardware stores can supply some DIY
hydroponics needs, certain items still require a trip to the
grow shop. While it’s often fun to try new things and save
money, there are certain elements of your hydro setup
you simply can’t skimp on.
When designing a hydroponic garden, one of the most
important choices will be deciding on a cultivation system.
Within this frame, many hydro growers opt for clay pellets
as their substrate of choice. Yet, there are many clay pellets
on the market, with some proving better suited for horticulture
than others. Of importance here is the notion of avoiding
construction-grade clay pellets in your hydro setup.
What are Clay Pellets?
Both the indoor gardening and construction industries utilize
clay pellets referred to as “LECA clay.” The term LECA is an
abbreviation for “lightweight expandable clay aggregate,”
which is also sometimes referred to as “expanded clay.” The
standout feature of LECA clay is how it is formed, with the
material expanding into extremely lightweight pellets when
heated at more than 2,000°F. Interestingly, this extreme heat
causes the clay to expand with air pockets, giving LECA its
signature light mass.
Clay pellets allow for excellent root zone health and drainage.
Clay Pellets for Hydroponic Growing
Clay pellets for hydroponic growing are made with the same
process as all LECA clays. However, special attention is paid
in manufacturing these pellets so harmful materials aren’t
accidentally mixed with the clay. As such, clay pellets found
at hydro stores are considered food grade because they are
free of harmful impurities. Therefore, store-bought clay pellets
such as hydrotons can support a plant’s delicate root system
without exposing it to harmful impurities.
There are many motives for choosing to grow crops in clay
pellets like hydrotons. To begin with, because they are lightweight
and porous, clay pellets retain water while also allowing
for excellent root zone drainage. Also, many growers
prefer clay pellets because they are considered pH-neutral
and won’t cause imbalances in nutrient mixes. Finally,
clay pellets are extremely durable and can be reused many
times as long as they are cleaned between harvests. While
these factors doubtless make clay pellets attractive for hydro
growing, it’s important you purchase the correct LECA clay
products for your needs.
“Because it is difficult
to determine the
precise mineral
composition of
construction-grade
pellets, troubleshooting a
hydro system with them in
play is virtually impossible.”
Issues with Construction-Grade Clay Pellets
On the macro level, construction-grade clay pellets are made
in the same way as other LECA clays. However, construction-grade
clay pellets are produced specifically as an ingredient
for lightweight concrete. Because concrete mixes don’t
require food-grade purity, this LECA clay is manufactured
with few controls in place regarding contaminants.
LECA clay pebbles are formed from standard clay that is
extracted from the ground. Generally, for construction-grade
pellets, LECA producers will utilize the most convenient clay
source in their manufacturing facility, regardless of quality.
Therefore, because there is a lack of quality control on this
clay, it could contain impurities that are harmful for plants.
Similarly, with a disregard for the good manufacturing practices
(GMP) that come with food-grade pellets, construction-grade
pellets can also be stored with potential contaminants
such as concrete, limestone, and mortar.
The contaminants found in construction-grade clay pellets
can lead to devastating pH imbalances in your hydroponic
setup. To this end, overabundances of minerals such as limestone
can cause unpredictable rapid spikes in pH levels that
can prove toxic for plants. Even more, because it is difficult
to determine the precise mineral composition of construction-grade
pellets, troubleshooting a hydro system with them
in play is virtually impossible.
There is also a concern that the inconsistent sizing of
construction-grade clay pellets could cause problems in a
garden. Unlike hydroton pellets, construction-grade pellets
are not sized with cultivation purposes in mind. Therefore, if
pellets are too small, they may pack too tightly and choke the
rootzone off from valuable aeration. Conversely, oversized
pellets may absorb too much water and wreak havoc on the
water levels of your hydro system.
Stick to What’s Proven
DIY hydroponics can be fun and educational. However, there
are certain elements of your setup where you should stick
with proven methods. Of these, it’s vitally important to use
cultivation mediums that are known to work successfully in
hydroponics. In the case of LECA clay pellets, it seems you
can’t beat the quality and reliability of products engineered
specifically for horticulture.
One of the most attractive elements of hydroponics is the
amount of control it allows you over your garden. To this
end, savvy hydro growers can make precise choices on
nutrient regimes and quickly pivot with imbalances of pH.
Unfortunately, adding a wildcard to your hydro setup like
construction-grade pellets removes many of the controls that
have come to define hydroponics. While it’s great to save
money on our gardens and try new things, sometimes it’s best
to follow proven standards.
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