EarthThat hydroponics is ecological is something you read and hear anywhere.

And that really annoys me. Why? Because this statement is often exploited in marketing strategies to entice us to buy quite expensive stuff.

The plants themselves are undoubtedly of good quality (no pesticides, but you can also achieve that with culture in soil) but the growing itself is not exactly environmentally friendly.

This article was conceived after the launch of a new range of products for hydroponics by Ikea.

Claiming that hydroponics is ecological, is simply nonsense. This is a pure marketing strategy that responds to the trend towards greener living but if you study it a bit, you will see that hydroponics is not as ecological as they claim.

The operating principle of hydroponics is indeed environmentally friendly:

  • water consumption is 70-90% lower than for culture in ground
  • it requires fewer pesticides
  • the efficiency is higher than in soil culture
  • several substrates are waste products or from renewable resources: clay pebbles, coco peat

But you need a minimum of material:

  • the fertilizer: is manufactured, packed in plastic bottles and transported to the store… that can hardly be considered ecological
  • the substrate has to be bought: the substrate itself may be ecological, the packaging and transport are not

And it may be necessary to buy additional accessories:

  • grow lights: grow lights are not environmentally friendly (they contain heavy metals), they also consume electricity which is rarely green. You use a solar panel? Okay, you get electricity from a renewable source but the solar panel itself is not ecological.
  • heating: no comment, very few heating systems are ecological.
  • pump: dynamic or circulation systems where the nutrient solution is passed along the roots of the plant, requires a pump. This consists of plastic and metal, must be manufactured, and then transported to the store.
  • electrical conductivity and pH meters: in large containers the conductance and pH must be regularly measured. The meters are made of plastic and metal, there are manufactured and transported to the store.

But are hydroponics then not actually green?

Whether hydroponics is environmentally friendly or not, depends mainly on the scale at which it is used.

Hydroponics in industrial horticulture is less polluting than traditional horticulture but yet it is untrue that there is no impact at all on the environment.

In industrial horticulture where roughly 100,000 plants are grown on an area of 1 hectare, the polluting impact on the environment (through the products and materials that you need, as well as consumption of electricity, fuel for transport…), is a lot smaller per plant than when growing on a small scale.

And it’s certainly less polluting than a few home-grown plants on hydroponics:

  • the packaging for the fertilizer (plastic) is relatively bigger for smaller amounts of fertilizer
  • 1 EC/pH meter for 100,000 plants instead of 1 for 20 plants at home
  • grow lights illuminate 500 plants instead of 20 plants at home…

Conclusion:

Hydroponics always has a polluting effect on the environment, mostly indirectly by accessories made from polluting material, through the manufacturing process of these accessories and transportation as well as the consumption of energy (electricity, fuel…).

The polluting effect is relatively lower per plant for large systems than for small installations.

The claim that hydroponics is an ecological way to grow fruit, vegetables and herbs at home is simply not true and certainly not if you use grow lights, pumps and other advanced equipment.

It irritates me to death when marketing messages claim growing vegetables, fruits and herbs at home on hydroponics is environmentally friendly to make you buy a complete kit with grow lights.

And if you want a circulatory system, you need a pump, EC and pH meters, bigger grow lights… and that’s even more polluting.

If you really want to achieve ecological gardening, use your garden or grow your plants in pots with potting soil and make your own fertilizer by composting or getting horse manure at a horse riding center of farm nearby.

Why then should you use hydroponics at home?

For house and patio plants in a simple system with passive or non-circulatory hydroponics, pollution is quite limited.

All you need are a plastic or other water tight container that can be reused, fertilizer and tap water.

You still have the advantages of hydroponics, mainly fewer pesticides since there are fewer pests and fungi in the substrate.

I use hydroponics mainly for ornamental plants because the plants are less affected by pests or fungi and it is easy to use: the gauge shows exactly when to water the plant, you never have to guess.

For fruit, vegetables and herbs indoors or on a patio, I rarely use hydroponics. Some plants are difficult to keep in the winter due to lack of light and I refuse to buy grow lights because I think they are not environmentally friendly.

I recycle PET-bottles and plastic containers for sowing. I have to ask them to family because we rarely buy drink in PET bottles (the drink itself is often not very healthy and the bottle is not environmentally friendly). And we rarely buy food in plastic pots, so I have to beg family for those as well.

Image sources

  • Earth: Own work

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