What’s the main source of confusion among beginner indoor gardeners? Well, many friends who work in grow stores tell me the same thing: it’s the word “hydroponics” and what it actually means!
Here’s an actual conversation between a buddy of mine, Gary, and a new customer. This is pretty typical of what I’m talking about:
Customer: “My friend has been into hydrotonics for years. Now I want to give it a go too.”
Hydrotonics? Ok, so this guy doesn’t look like the type to be into water-based healing remedies but hey, you never can tell. The customer continues …
“Isn’t that what this shop is all about? Growing plants indoors under lights and stuff?”
Store owner: “HydroPONICS is NOTHING to do with growing plants under lights!”
The customer is taken aback. Confused, he swivels his head around to the grow lamps on display behind him, then he turns back to the store owner as if to ask, “So what the hell are all these grow lamps doing in here then? This is a hydrotonics store, right?”
I want to leave that conversation right there for now, but please allow me to repeat: Hydroponics is nothing to do with artificial grow lights. Forget about them. Forget about lamps, ballasts, reflectors, ducting, extraction fans, carbon filters and many of the other things you might find in your local grow store. Many of these items are very useful for setting up an indoor garden – granted. But the subject for discussion here isn’t indoor gardening. It’s hydroponics. So let’s get started.
What is Hydroponics?
Ok. First the Greek: Hydro = water. Ponics = working. Hydroponics, roughly translated, means ‘water working.’ But what does that really mean? Well, some debate still exists over the precise meaning of the word in practice. But the first and perhaps most important principle to understand is that plants grown hydroponically are not grown in soil. If this sounds crazy to you, first understand how things actually work in soil. A plant grown in soil sends its roots into the soil in search of oxygen, water, and nutrients. Soil is generally made up of particles of rock and decaying organic matter. Some beginners think it’s a weird concept to imagine oxygen in soil, but all we’re talking about here are small air gaps between soil particles. Don’t forget: oxygen is absolutely vital to root health!
Plants absorb the nutrients they need via their roots in the form of inorganic ions contained in water. In natural conditions, soil acts as a sort of cache for mineral nutrients. The important thing to understand here is that the soil itself is not the vital thing. You don’t actually need it! You can isolate the mineral nutrients that are present in good soil and dissolve them in water instead. All plant roots need in order to thrive is access to this nutrient solution and oxygen! So soil can be taken out of the equation completely.
You can grow plants in sawdust, coconut husk, clay pebbles, and all sorts of other ‘inert’ substances (inert, in this case, means the substance has no nutritional value in itself). It only becomes viable once you add the nutrient solution. You can even grow plants in the nutrient solution alone – as long as it is well oxygenated. The unifying principle here is this process of taking the required mineral nutrients and adding them to water artificially – this is the basis of hydroponics. The water is doing the “work” instead of the soil.
This begs the obvious question: why bother? Why go to the hassle of getting hold of the mineral nutrients a plant needs and dissolving them in water, instead of just letting the plant get what it needs from soil in the first place?
It All Comes Down To Energy!
Let’s go back to looking at what a plant needs. Above the surface, plants need light and air. Below the surface, plants need water, nutrients and oxygen. Why? Well, light is the motor of photosynthesis. Photosynthesis is the name given to the conversion of light energy into chemical energy. It’s this chemical energy (oxygen and carbohydrates) that a plant uses to develop.
It’s helpful to imagine this energy as a finite resource. If a plant needs to do anything, like grow a new leaf, thicken some stem, produce a flower, fight off a disease or set down a new root, it needs to invest some of that energy. Picture that energy supply getting smaller and smaller as it performs all these energy-dependent tasks.
Continuing with this energy idea for a moment … soil-grown plants typically have to produce larger root systems in order to fully exploit all the nutrients, oxygen and water necessary for them to grow and develop. This takes energy! Now, imagine if all the nutrients, oxygen and water were available directly and close by, without the plant having to create large root systems to find it. It’s a bit like the difference between dialing a number for a pizza to be delivered to your house instead of walking to the shops, buying the dough ingredients, toppings, grating the cheese, and cooking it for yourself. If a plant doesn’t need to invest lots of energy into creating huge root systems it can redirect that energy towards producing more stems, leaves and flowers – which, in turn, creates more energy! Do you get my exponential drift here? More energy spent on creating leaves that, in turn, generate more energy!
So this is one of the reasons why plants grown in hydroponics develop faster than soil-grown plants. They don’t have to spend so much energy creating roots to find nutrients, oxygen and water in the first place!
Keep Stress to a Minimum
Let’s look at another aspect. A common problem with soil gardening is over or under-watering. Or in other words: not enough oxygen (because the soil has become compacted or saturated with excess water), or not enough water. Under-watering is less of a common problem. However, many gardeners who grow using containers experience it. Not enough water dries out the root hairs, causing them to die. This, in turn, stunts growth. Both over and under-watering cause your plants to suffer from stress and increase the likelihood of disease.
Plants grown in an active hydroponics system have access to nutrients, water and increased levels of oxygen all the time! There’s no perpetual ‘too wet, too dry’ stress – meaning plants can get on with the business of growth and bloom rather than wasting precious resources on self-protection. Growing plants in hydroponics is a far cleaner environment too – there is far less potential for harmful pathogens in a hydroponics solution than in soil.
Finally, let’s not forget that you can far more easily control the nutrients your plants have access to in a hydroponic environment because you are totally responsible for it! (There are two sides to this coin however … certainly soil affords the grower greater margin for error!)
To sum up then, here are some advantages of hydroponics over soil:
- Increased control over the plant’s rooting environment
- Hydroponic systems cut down on your manual labor
- Water can be conserved through recirculating the nutrient solution
- Smaller root zone means less floor space required
- Faster growing time means you don’t have to wait so long between harvests
- Pest, weeds, and diseases can be more easily prevented / controlled
- Hydroponic plants do not have to deal with soil borne pests
- Much higher yields!