Building Your 1st Indoor Grow Room

OK, you’re convinced. You want to set-up a grow room and you want to start growing indoors – but where do you start? It can be very confusing when you’re starting out. Take a tip from us – a well planned grow room will make your life a lot easier.

The Basics. Keeping it simple

Before you build your grow room and start growing there are a few things you should keep in mind. Indoor gardening is easy – not even remotely difficult unless you make it hard for yourself. All you need to do is build a simple grow room with good light and air exchange, add some good healthy stock and look after your plants well. Excellent results are easily achievable however you decide to grow. Whichever method of growing you choose (Hydroponics, Soil or Coco), following some simple standard methods and practices will give you a good base to develop from and add more advanced skills as you progress. The best way to make your indoor garden as efficient and easy as possible is to put some thought into your grow room. A well thought out and constructed grow room will make your life so much easier – so where do you start?

Choosing a suitable space

Almost any space could be used for a grow room, from a small cupboard to a whole room, garage or attic space. You can either convert a whole room or cupboard into a grow room, or use a grow tent or chamber within a room to create an enclosed growing space.

An electrical supply source is also needed. For a one or two light set up a couple of normal double wall socket would be sufficient.

A nearby water supply is vital as your plants may get very thirsty under all that light. We recommend tap water over rain water as it gives you a much cleaner and safer base liquid on which to build. Rain Water will already contain many elements and could also carry diseases or fungi that could harm your plant.

Lights and pumps may be on at night creating a small amount of noise, so you need to consider the placement of your grow room in relation to bedrooms/neighbours etc that you do not want affected by your grow room.

Do not grow on carpeted floors as these can both hold moisture and harbour bugs and bacteria. Ideally remove any carpet and line the floor with thick black/white reflective sheeting or seal with pond liner if possible leaks would cause you a problem.

Even if you have a small window or natural light source in your growing area you may want to block it off or light trap the area with reflective sheeting. This is because you will want to seal in any light that may escape from your grow room and because natural light could affect your plants growth. Because of the cost of electricity, many growers decide to have their lights on during the night and their lights of (dark) period during the day. Any natural light that gets to your plants during this lights of period could confuse the plant and affect its growth.

The main consideration is that whatever area you choose you will have to give that area air exchange, provided usually by an extractor fan. The smaller extractor fans are very quiet, but the larger extractor fans can be noisy. As a general rule, the more lights you have the more air exchange you will require.

Extractor fans are normally on 24 hours a day when run with carbon filters. The extractor doesn’t have to be in the grow room, it can be placed outside the room and run in line with ducting.

To help avoid heat problems, especially in summer, try to make grow rooms at least 180cm (6”) tall. If your garden doesn’t have this headroom then you may want to consider using smaller lights or a light rail.

Most of our grow lights produce very high light levels. We supply 5 different types of reflective sheeting, including Total Blackout sheeting, Mylar and Orca to help lightproof an area, build reflective grow tents with, and make walls more reflective.

Extractor fans, ducting , clips, brackets, reducers, tees, elbows, tape, chain, hooks, 35mm plastic modular framework and fittings, and other accessories are also available at GroWell.

Build Options:

Converting a whole room

Generally it’s best to match the size of area to the amount of light. There would be no point using a 600 Watt light in a 20 foot x 10 foot room. You’d be better off using a Tent to trap the light in and maximise growth/yield.

If you do have a small room and want to use the whole space, then use one 600 watt light every 5 or 6 feet, the more lights you have the bigger extractor fan you will need. There’s a nice chart in the blueprint section of our catalogue that can help you work out your extraction requirements, or call alternatively you can call our technical team on 0845 345 5176. Remember air needs to enter the room as well as leave, some air input holes and/or input fan should be used to bring new air into the growing room from a friendly temperature source like from inside the house. Hot air extracted from the top of the grow room should ideally leave the building. Your input fan should be a bit smaller than your output fan.

Converting small areas like walk in wardrobes, closets and cupboards

When in small spaces and closets try and have your grow room as tall as possible – at least 5 feet even with only 250 Watt lights. Ideally, you want even more headroom than this to prevent possible future heat problems. If you don’t have this sort of headroom then you may want to use a smaller light like the Bright-Wing high output fluorescent unit, or ideally find a bigger area to grow in.

In small areas with 250, 400 or 600 Watt lights it’s best to use an extractor fan to take the hot air from the top of the room and air input holes around the bottom of the area for new air to enter the area. Better still, an air input fan can also be used to force new air into the grow room and create a constant flow of new air in and old air out. This will keep the area as cool as possible enabling the use of nearer optimum light levels and better results. When using an input fan, keep the air input holes and use a smaller input fan than output fan.

When only using one or two lights ideally want to use input air from an indoor source at a friendly temperature. Your extracted hot grow room air should be ducted outside, or at least away from the plants into the rest of a larger room which is well ventilated. Your main concern is to get the hot used air away from the plant tops and out the growing area, it can be re-circulated with the air from the larger room as long as that room is well/regularly ventilated.

Grow room within a room

GroWell Grow Tents are very popular because they can be set up quickly in any space to create the perfect growing area without it infringing on the rest of the room. They are constructed of highly reflective Total Blackout Sheeting to trap the light in and maximize yield. An extractor fan is then used to create some airflow through the tent, either taking the air completely out of the building or mixing it back into the rest of the larger room. Grow-Tents are very popular and contain all the growing, light and environmental factors into one distinct area and therefore protecting the larger room from the heat and humidity. These tents are made from 35mm square plastic framework and connectors and can be easily erected and taken down again many times making them often more practical than wooden structures.

Whether you decide to buy a grow-tent, build your own growing chamber or section off part of a room, we should have everything you need to create a good lightproof growing environment. The blueprint section of our catalogue contains a number of grow room set-up diagrams to get you started.

Along with a suitable size Grow-Tent, for a basic set up you would also need:

a suitable Light system

a suitable relay and timer system for the light

an extractor fan (for one 600 Watt light we recommend the RVK 125 fan)

ducting and quick release duct clip

That’s about it for the grow room, now you just need to choose a growing system for the plants. Hand watering in pots is very popular, especially in coir, but a small hydro system does make it easier for the plants to cope with intense light environments and heat.

Get The Right Light System

For most high light gardens we use high pressure sodium light systems. These come in 4 basic sizes:

250 Watt: very popular for a first time light, or for smaller areas like cupboards, still gives good yields

400 Watt: very popular, good for vegetative plants, small grow rooms or larger grow rooms with limited headroom

600 Watt: the most efficient and popular size. Gives optimum light and good depth over an area of 4 foot by 5 foot or more

1000 Watt: Extremely powerful light systems that are best utilized on light rails where they will cover an area of about 9 foot by 5 foot

If you’ve got a small closet type area a 250 watt sodium light will give great results from start to finish, although at least 5 feet grow room height should be used. If you want a small area to use purely for propagation and early vegetative growth, then a high output Bright-Wing fluorescent unit may be the answer, the minimum grow room height for this unit is at least 4 feet, preferably more.

If using a high pressure sodium light system you will need to use a relay to protect your timer from blowing as the inductive current that fires the lamp up is very high and will cause the timer to fuse and stay on. Call our Technical Team on 0845 345 5176 if you need help getting the right Light or Timer system.

Air Exchange

As mentioned earlier, air exchange is a key ingredient to a successful grow room. The ideal air exchange rate will vary at different times of the year and from room to room depending on things like grow room height, etc. As rough guide about 30 air changes per hour is often recommended. Personally we like to also work on at least 200 cubic metres of movement per hour for one 600 Watt light, then 150m3/hr for each extra light. Then compare the two figures for each method and go for an average between the two and you won’t be far out. Adjust this figure slightly up or down for 1000 Watt or 400 Watt respectively.

Basic Grow Room Safety

Grow light systems are very safe. They use a few hundred watts – no more than many other household electrical items and like any of these items are perfectly safe if used with common sense and a healthy respect for electricity.

Run cables neatly and out of the way, position ballasts and any other electrical equipment where it will not come into contact with water unless specifically designed to do so like nutrient heaters and water pumps.

From time to time check all installations, connections and wiring.

Make sure equipment is not accessible to children or animals.

Read instructions and safety information where applicable, especially where aggressive liquids are concerned.