I’ve asked myself this question countless times. Walking around a new property I hear the little voice inside my head weighing up each room, every nook and cranny, all with a view towards potential veg production. “Can I grow in here?” “How about in here?” “What about up there?” Yeah, I know, I sound like an obsessed little kid. But it’s not far from the truth. Growing indoors is more than just a hobby for me. It’s my life’s passion. So while the letting agent or realtor is trying to impress my wife with designer taps and garish bathroom ceramics, I’m speccing the place out for potential growing action. I mean, common boys and girls, do you really feel like you’ve moved into a new place until ALL the lights are on? Exactly.
Over the years the obsessive little kid’s voice has grown up, well just a little. Experience has taught me to ask a whole bunch of crucial questions when evaluating a potential grow space. I’m not talking about whether the wife will get mad if she returns home to find her walk-in wardrobe magically ‘transformed’ into a propagation station. She knew what she was taking on when she signed on the dotted line in front of the registrar! In fact, these days she doesn’t even complain, bless her. Maybe it’s something to do with the access to fresh homegrown salads she enjoys year round? In fact, it’s amazing what a steady flow of leafy greens can do for a relationship!
Anyway, lest we digress, let’s get one thing clear. When I ask, “Can I grow in here?” I’m not referring to obtaining permission from your spouse or anybody else for that matter. I’m talking about how we go about assessing the viability of a given space for indoor gardening. So, let’s dispense with the celebrity gossip and get on and do this!

1. Insulation

The better your indoor garden is insulated, the easier it will be to grow in it. Many indoor gardens suffer from excessive heat problems, especially during the summer months when ambient temperatures are considerably warmer. High temperatures can slow plant metabolism and stress your plants causing them to respond in unfavorable ways. This isn’t just a euphemism for death either. Many culinary herbs and lettuces will ‘bolt’ into premature flower and seed production if they are forced to endure prolonged high temperatures. Similarly, if nighttime temperatures drop too low this invariably stunts growth and bloom. Cold, poorly insulated rooms cause very slow growth, poor water and nutrient uptake, and low temperatures can cause further undesired changes in your plants – e.g. chili peppers will fruit prematurely if nighttime temperatures drop below 65°F (18°C). So remember, the better a potential grow space is insulated, the greater the “base level” of protection from extremes in ambient temperature and the less money and effort you will have to invest into controlling temperatures in your indoor garden. Is it really worth all the energy, money and time investing in a state-of-the-art cooling system to chill your grow lights in a ramshackle loft apartment in Los Angeles, or will it simply be cheaper and easier in the long-run just to move to somewhere more suitable? Now’s the time to ask yourself these questions!
Take a moment to think about the general characteristics of your house or apartment. What is it made of? Wood, stone, brick, concrete? How thick are the walls? What type of insulation has been used? Not sure? Ask yourself these questions: Does your home already get too hot in the summer, and is it a pain to keep warm during the winter? In either case – not a good sign! What about your indoor garden’s location within your home? Is it in a room at the top of the house that has an external wall facing the sun all day? Or is it cool and shady? Hopefully you’ll be nodding at the latter.
Insulation is measured by its R value. The higher the R value, the more effective the insulation. Some of the best insulation materials are:

• Blown in Cellulose Insulation – R3.70 per inch
• Fiberglass Insulation – R3.14 per inch
• Expanded Polystyrene – R4.00 per inch

Many growers report their greatest successes from gardens located in a cellar or basement. And there is a good reason for this – the amazing insulation qualities of the earth! So whether you are storing wine or growing food to accompany it, a basement can be ideal. (Just don’t do both at the same time!) Basements can be subject to high humidity, so you may also need to invest in a dehumdifier. Their subterranean location can make getting rid of spent nutrient solution more tricky than usual.

2. Ceiling Height

Look up. What do you see? Hopefully it’s a ceiling high above you, well out of reach. 8 ft ceilings are okay. 10 ft or more is a godsend for any indoor gardener – that extra air volume makes your life so much easier, believe. Not only do you have more height to grow climbing varieties of tomato, peas and beans but, once again, you will find your temperatures and CO2 levels far easier to maintain and control. Additional ceiling clearance means that you also have the option of raising the height of your grow trays so that your garden is easier to work in, with the additional benefit of making drainage / nutrient return easier to manage using plain old fashioned gravity alone.

3. Water

Your plants want a lot of things – some of them desirable, some of them essential. One thing they can’t possibly go without is water! Prior research into the water quality of the area will be useful. Generally, the softer the water the easier it is to grow with. Hard water can still be used to produce productive crops but a lot of growers now use RO machines to remove the carbonates and other contaminants. Indoor gardeners commonly use a large container such as a rain collection barrel to mix and store their nutrient solutions – often referred to as a reservoir or ‘res.’ Ideally this should be kept in an adjacent room so that your nutrient solution is not subject to the temperature changes in the growing area itself. Think about where you are going to store your nutrient solution and its location relative to your nearest water source. Running hoses across landings or up and down stairs is a pain and invariably leads to leaks and spillages. I’ve lost count of the amount of times a hose end has flopped itself out of a res, spewing water all over the floor. It’s a nightmare scenario! Filling up your res is a regular chore, so make your life as easy as possible with sensible planning and, ideally, a dedicated tap right above it. The less hose pipe in your life, the better! (My wife hates seeing hose pipe running from room to room!)

4. Drainage

It’s not just about getting water into your indoor garden. What about getting it out? Is there an easy way to drain your spent nutrient solution? Once again, it’s all about making life easy for yourselves! Most growers use a submersible pump and hose to drain their reservoirs. Some growers recycle their spent nutrient solution by using it on their outdoor gardens too.

5. Ventilation / Windows

Unless you are growing in a sealed room with AC and CO2 supplementation, you are going to need to install some sort of ventilation in order to keep on top of temperature, humidity and CO2 levels in your indoor garden. Many novice growers grossly underestimate their ventilation requirements. Remember, all that hot, CO2-depleted air needs to go somewhere. And then it needs to be replaced with cool, clean, fresh air of course! Simply pumping air out of your grow tent back, for example, into the same room it’s situated in does not count as adequate ventilation. We need to transport the old air well away, and keep the fresh air … well fresh!
Think of your ventilation in terms of input and output. In order to maximize your control over your indoor garden’s environment you should always spec the size of your output (aka extraction) inline fans bigger than your input. More air being pumped out than being pumped in creates a ‘negative pressure’ which ensures zero air and odor leaks and also increases the efficiency of your input fans. If you are using carbon filters with your input or output fans, remember to take into account their diminishing effect on their respective fan – often a 25% reduction factor is used but depending on the make and age of the filter it could be anywhere between a 10 – 30% reduction.
Extraction has the most positive effect on reducing temperature when it is removing air from the top of a room – as hot air rises. Ideally it should be vented out of the property to the outside world. As far as intakes are concerned, be aware of where you are taking your air from. Drawing ice-cold air direct from sub-zero temperatures outdoors and blowing it directly on your plants is not clever. It’s a far better option to draw air from a cool room in your home instead. Be sure to use a bug screen on all air intakes. Yes, you will have to spec up your fan by 10-30% to counter the increased air resistance, but at least you won’t be drawing bugs, mold spores and pollens into your indoor garden!

Size and Accessibility

Remember, you need space to work and get around in your garden. Ideally you should be able to access your growing area from all sides, allowing you to inspect all your plants with the same level of care and precision. Overfilling your garden, however tempting, will quickly turn maintenance into an onerous, back breaking exercise. Remember, your hobby should be a pleasure, and not a chore!

Pest Protection

All carpet should be removed from any space where you are planning to grow as it can harbor no end of pests and pathogens. If removing the carpet is not an option, you can lay down protective plastic sheeting. Remember, your indoor garden should be as easy as possible to keep squeaky clean. A laminate floor that is easy to mop is ideal. Air intakes should use a bug screen so that you don’t inadvertently suck bugs into your garden.

Next issue: Electrical Safety in your indoor garden – so important, we need to tackle this subject on its own!