Why Soil And Not Hydroponics, And Vice Versa
I have decided that is high time we tackle this topic as my next article because in fact is a pretty hot topic of conversation. Especially in Berlin, where we have incredible startups like infarm, who specialize in hydroponic production in urban areas, supplying restaurants, supermarkets, and much more, and therefore cutting down on the food miles as in most places their setup is installed in-house.
Also, I’m finding that friends left right and center are getting themselves home hydroponic kits to grow exciting salad varieties. So we’ve often find ourselves talking about why we use soil instead of hydroponics, and so we wanted to give a bit of an overview of the pros and cons of soil versus hydroponics.
So then let’s go back to basics, what is hydroponics? Hydroponics, in a nutshell, is a method of growing plants without soil, where you use mineral nutrient mixes in a water solution (hence the word ‘hydro’). Generally, the plants are grown with their roots exposed, whereby the water and nutrient mix is introduced by either the roots sitting within the mixture, being sprayed or in some cases having partial drying and partial immersion. In other cases where plants require support to their root systems perlite, rock wool and gravel can be used. The nutrient solutions utilized can be those produced by the multiple companies that have begun specializing in this, or you can mix up your own (with access to a lab-type stock of elements), by-products of aquaculture farms, fish waste, etc. can also be used. Generally, hydroponic systems that most homeowners utilize for home gardening are a fully controllable unit including lighting. Therefore enabling growers to control and produce a very efficient plant in the best conditions that you choose.
Economic investment
This all might sound ideal to some, but actually, there are a few things to consider here. Firstly the economic investment required in the beginning is rather substantial. These systems are not always cheap. Or let me put it this way, if you want good lighting which are in the right ‘spectrum’ and are not going to give you leggy unhealthy plants, you want a good system that has been produced by a trustworthy company. And whilst these sure exist, say Ikea even does great systems their not cheap, it adds up financially. Whilst in comparison when you’re doing home balcony soil based gardening you can do so without investing tons of money in the beginning but build it up slowly, all you need is some seeds and soil and you can recycle egg cartons to your hearts delight for seedling trays and bang you’re on your way in springtime!
Energy reliance/plant compounds
Now another thing to be concerned about in terms of hydroponics is that its energy reliant. So if you’re in a place where the electricity tends to cut out, or you don’t fancy using unnecessary energy but conserving then this is really something to consider. If your lights go out, your plants will die. Sadly that’s just the reality, it’s a very fine-tuned system and you can get great productivity out of it, but at the same time, these plants produced in such systems are not as resilient as those grown in natural conditions. And that brings us to the next major point to consider. Natural conditions tend to enable plants to develop a buffer capacity against changes in temperature, lack of water, etc. They toughen up and produce all kinds of amazing secondary metabolite plant compounds that help protect them from the stress. And guess what- science is just discovering how healthy some of these compounds are for us, humans! Secondary metabolites called ‘glucosinolates’ in the broccoli family have been found to have anti-carcinogenic properties! So plants toughening up to growing conditions can be a good thing for them and for us.
Maintenance / disease
Now whilst there is a whole hype in controlling ‘lighting’ recipes that LED’s can now create for plants, and some home growers are tweaking their tomato plants for example to increase flavonoid secondary compounds. This is realistically a bit more on the advanced side. And essentially hydroponics can be even harder for the novice gardener because the plants are not very resilient or forgiving. They are fragile beauty queens that have never had a stress in their life and really throw a temper tantrum when things go a bit unusually out of schedule. This importantly enough brings us to another point, that hydroponic systems are very controlled clean and uncontaminated. This usually means then that if one plant gets a disease, a virus or is afflicted by something you can pretty much count on all the other plants being afflicted or struck down by the same thing within days. All plants are grown in the same water mixture and this just causes disease and contamination to spread extremely fast. So you have to really be quick on the draw in identifying a malady or symptom when it crops up.
Organic?
Now another aspect if you were not aware of it, an interesting fact, organic produce will not be certified so if grown using hydroponics. Why you might ask? Because one of the underlying most important rules for organic certification is that organic produce in grown in soil. There has been a huge push to get this removed as there have been increasingly more sustainable organic fertilizers and nutrient mixes being made for hydroponics that were not available a few years ago. But I must say that I think it might be an important gold standard to keep in play. Soil is so important, and actually is also such a reserve of all kinds of micro life and activity that when cared for and given back to in exchange for the harvests and bounties you are getting out of your balcony or garden, can become enriched and magical. There is a whole micro magical world of fungi and organisms that aid in the breakdown and transport of nutrients from the air into the soil and to your plant’s roots that are just mind-boggling. So when you create a healthy balanced soil you are in for a win-win situation of constant giving in exchange for a bit of compost and humus content every year. It’s pretty satisfying I must say!
Big companies?
Also back onto the topic of minerals and fertilizers, this is not so far off from the monoculture system many of us are trying to not support by, in fact, growing our own and sidestep the big agri-companies. Hydroponics sadly is fertilizer based, and one very important aspect to consider even when using organic biofertilizers is where and how is this product produced? It’s very often the result of mining activities in a developing country where workers are not living in healthy socially justifiable conditions. Additionally, a lot of ‘producers’ of chemicals required for the creating of these mixtures are big pharmaceutical companies. And essentially I still have a hard time justifying such high externalities when liquid manures and composts can be created so easily at home in even space limited flats. Additionally, the production of hydroponics growing facilities and systems is very energy-intensive to ‘build’ or manufacture. And so if you have access to a windowsill or balcony with sunlight or even semi sunlight I would be more in favor of encouraging gardeners to branch out and explore that area first. I especially cannot wait in spring for those first warm days to go and begin organizing and sowing and get growing. There’s nothing better than fresh air and sunlight and actual dirt under nails in my opinion but that’s just me. Also, let’s not forget how much the insects and bees thank us for the plants and flowers that are provided to them from our outdoor growing activities.
Cons of hydroponics
Now I know I’ve banged on about the cons of hydroponics a bit and I going to try and redeem myself here a bit. Because trust me living in Berlin and being an urban gardener by profession, the idea of growing things indoors in winter really is starting to get under my skin. So for me, this is where the plus can come in. If you have no balcony or sunny windowsills then these systems can be incredible. In fact, I’ve even visited fantastic bars that grow all their medicinal plants indoor year long using beautifully handmade hydroponic shelving systems. So I have been secretly scouting out a section in our flat for a little homemade DIY winter growing because let’s be honest, this green thumb gets super itchy and would love to have some things to play within the winter. I also really like the idea of homegrown winter veg and salads during the winter and being able to see the results of lighting and nutrients first hand, and sadly my flat is incredibly dark year-round with not an inch of sunlight all day. Now my only constraint is all the points I’ve mentioned beforehand, especially as I am blessed enough to have an urban garden here in Berlin that I share with friends. But you know where I think the pay of is going to come? In the summer because fantasizing about all the amazing seedlings I could start of early with a hydroponics system here in the flat. So I guess to finish off- to each their own. But for me personally? Nothing beats being outdoors with dirt under my nails!
Lead photo by Emile-Victor Portenart on Unsplash
Natasha Weddepohl
From market gardening to urban permaculture projects, Natasha has been involved in a multitude of projects linked with food growing and sustainability, for over 12 years. Originally from South Africa, she has gained her experience in sustainable food production through hands-on work worldwide. She is currently based in Berlin, assisting a few projects, whilst completing an MSc in Horticultural Science.