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The pros and cons of growing vertically and horizontally

At its core, vertical growing is a very simple concept; if you lack the floor space to grow horizontally then you can tip your whole system 90 degrees and grow your plants sideways. The practicalities of doing this aren’t so simple. There are products, self-contained units, on the market which ingeniously deal with the inherent problems. Of course it’s never that simple and vertical growing has thrown up a number of further issues along the way. Some people swear by vertical growing, others think it’s little more than a gimmick. Both parties love to argue about it. So what’s the truth of the matter? Who’s right and who’s wrong? Well, let’s lay out the issue and see if we can’t get to the bottom of it.

Classical wisdom dictates that growth mediums are laid flat on the ground with a horizontal bulb placed at a particular distance above it. So whilst the growth medium and the bulb are both positioned horizontally, the sum of the constituent parts are arranged along the horizontal plain. The inherent problem with this is that only a portion of the bulb is directed towards the plant. Reflective hoods and materials go some way towards dealing with the problem, but there is an argument to be made that these materials refract the light in such a way that the light’s efficacy is diminished. Vertical growing aims to solve the problem by positioning the bulb and the corresponding growth medium vertically, with the plants arranged around the sides of the bulb, thereby utilizing the full 360° arc of light produced by said bulb. Technically, in this case, the sums of the constituent parts are arranged on a horizontal plain.

The coliseum arrangement is the most well-known configuration of vertical growing in the hydroponics industry, with the ‘Ecosystem’ being the most recognisable example of this. Plenty of people believe it to be the only configuration though, which is one of the major contributing factors to the considerable disagreement over vertical growing’s worth. Since most of the arguments for and against vertical growing refer to the coliseum arrangement, we’ll start there before looking at alternative arrangements.

  • Fewer bigger plants
  • More choice in systems
  • Wider spread - less disease prone
  • Cheaper setup cost
  • Better for taller crops (Sunflowers)
  • Takes up more floor space
  • Less efficient use of light
  • Closer to floor - more backbreaking

Space, the limited frontier

If you’re not already up to speed on how light works in the context of growing, check out our ‘Making Light Work’ series. In the coliseum arrangement, the distance between the bulb and the plants is fixed, which negates the problem of the diminishing efficacy of light over increased distances. Proponents of vertical growing claim that this means your light usage is more efficient. This is true to an extent, but it comes at a price; plants have less space in which to grow and the distance between the growth medium and the light source is fixed. This relative lack of space has to be compensated for by altering a number of other aspects of the grow.

Obviously tall, gangly plants don’t fair too well in a coliseum arrangement; short, stocky plants are your only real option. Phototropism dictates that plants grow upwards, towards the light source. Plants in a vertical system still have a tendency to grow in a general upwards direction, which is great news for Basil growers, but not so good for Sunflower fans or any growers of top heavy crops.

Vertical growers can push out at least one additional crop per year. In financial terms, that isn’t something to be sniffed at.

Cuttings put in a coliseum need to be old enough to handle a relatively short veg period, which means more time spent developing your cuttings. The advantage of a shortened life cycle is, of course, the ability to grow more crops in a shorter space of time- Vertical growers can push out at least one additional crop per year. In financial terms, that isn’t something to be sniffed at. Horizontal purists argue that much of the time saved in a vertical grow is negated by the extra workload involved in developing your cuttings or seedlings before putting them in the vertical system. Obviously all those young plants also need space in which to develop, too.

It is a widely held belief that the curved glass cooling tube which the bulbs sit in, in a coliseum setup, acts to diminish the effective output of the bulbs by 5-10%. Many vertical growers remove the glass casing and compensate for its absence by increasing the amount of cool air being fed to the bulbs. This has the added function of making it easier to change the bulbs where appropriate during a grow, something which can be a nightmare when using the glass tubes. If airflow is a particular problem for you, then it could be argued that you’re simply shifting the problem from one aspect of the grow to another. We will be looking at airflow elsewhere on the site and getting to grips with just how different air quality is, dependent on where your grow room is situated.

  • Lots of plants in a small area
  • More efficient use of light
  • Often easier access to plants
  • Better for smaller plants (Lettuce)
  • More prone to spread of disease
  • Small, stocky plants - harder to crop
  • Often expensive equipment cost

Close quarters

Plants in a coliseum arrangement live cheek to cheek, so the spread of diseases and funguses are a real worry. If you don’t catch a problem quickly enough, your crop stands a strong chance of being ravaged. In reality this problem has more to do with the practices of the grower than any inherent problem with the vertical system. Good plant spacing is a worthwhile practice in any grow room, be it horizontal, vertical or any other arrangement. Vertical growing doesn’t necessitate ramming in as many plants as possible, but because most vertical growers are aiming to eke out the maximum yield per wattage of electricity used, they tend to fill their grow rooms to the brim.

At this point you may well ask; what self-respecting grower would be so deficient as to allow his entire crop to succumb to a disease? Well, there is a misguided perception that a self-contained unit like the Ecosystem requires less maintenance then a conventional setup. Vertical growing units aren’t cheap and it isn’t hard to imagine a less than scrupulous retailer selling this high end stock as a save-all solution to an unsuspecting newcomer. The basic rule still applies; the more plants you have on the go at any particular time, the more time you’re going to need to spend taking care of them.

It’s all about the money, Baby

Commercial growers aim to maximise their yield relative to the amount of electricity used to grow the plants. Vertical growing has the potential to do just that, but it comes at the expense of other factors- predominantly your workload. That’s not to say you can’t maximise the size of your yield by increasing your workload in a horizontal grow room, but in that case you are likely to be limited by a lack of growing space. Really it comes down to what your motivations are.

If you’re a hobby grower, then vertical growing still offers you the opportunity to make the most of a limited grow space without using the coliseum arrangement. Bookshelf and stadium arrangements aim to make the most of a limited floor space. Horizontal and coliseum arrangements both tend toward producing top heavy plants, whilst these alternative arrangements aim to maximise flower or fruit production by offering the whole plant a good dose of available light, unimpeded by a heavy, or thick, canopy. We’ll look at these alternative arrangements, and indeed we’ll take a closer look at the coliseum arrangement in future articles.

Ultimately there are no hard and fast rules. It’s nearly impossible to define one system as being superior to another when there are so many contributing factors to consider. Choosing which arrangement to use depends on the space you have available, what you’re hoping to achieve and which system you feel works best for your individual needs. Vertical growing opens a door to thinking in a way other than laterally about how we utilize the space available to us. It’s a stepping stone on the path to new avenues of growing, not the ultimate destination.

I know, I know, we’re avoiding the question of which is better, horizontal or vertical growing. Well answer me this- which is better; Kung Fu or Karate? Strawberry jam or raspberry jam? Blackpool or Bournemouth? Cats or dogs? Made In Chelsea or The Only Way Is Essex? That last one was a trick question; they’re both harbingers of the Apocalypse, but you get the idea.

Maximising your yield is all well and good, but it isn’t necessarily better than maximising the quality of your crop, and it definitely shouldn’t come at the expense of having a grow room in which you’re happy to spend your valuable hours doing what we all love to do. Gardening, any kind of gardening, isn’t all about arriving at the perfect end product. If it was, surely you would simply buy the end product? Gardening is about the process. It’s a journey which wouldn’t have the same resonance if it was ever ‘perfected’. We’d be foolish to draw a line in the sand, but that doesn’t mean that you can’t. If you’re a particular proponent of either medium, pop your manifesto in the post to us and we may just give you the airtime to voice your opinion to your fellow growers.


This article was originally published in Issue 002 of HYDROMAG (November – December 2012).

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