Ventilation is the key to a good growroom. If you do not have enough fresh air, and a suitable temperature, plants can suffocate. An exhaust fan, especially the steel ball bearing types are quiet and much more efficient than 10 of the budget ceiling fans. Ideally you should have a fan with an air exchange of 10 to 15 times the growroom size per hour. Remember, the more fresh air the better. Carbon Dioxide Enrichment systems are fine when a grower is experienced, but to a beginner they represent more problems than they are worth. Ask a Store for advice.
The results of using lighting in an indoor environment are at least remarkable.
The benefits of controlling a plants environment are numerous, and you should speak to your local Hydroponic Store about the results obtainable.

When indoors you must bring in all that is present outdoors naturaly into the growroom, with good fresh airventilation, fresh air is inexpensive and real easy to find. fresh air is one ofthe most overlooked factors. Experienced gardeners know the importance of freshair and take alot of care to set up a proper air movement.
The main threefactors are, stomata,ventilation, and circulation. lets start with STOMATA whichis  microscopic pores  located on the underside of the leaves. the stomataregulate the flow of gasses in and out of the plant. it is very inportant tohave air movement to keep these pores clean and free of filmy residues, dust,
pollen etc.

If you want your plants to grow quickly and stay healthy, it’s important that you keep them within
their ‘comfort zone’. This is between 70-80°C. Most plants are very comfortable up to 80 °C, but are
sensitive to higher temperatures.

Plants are very sensitive to differences in temperature between the light cycle and dark cycle. To measure the night and day temperature you need a max-min thermometer. If you want fast vegetative growth, you need to try and keep your night and day temperatures as close as possible. However, to promote flowering and fruiting, you need to increase the difference between night and day by + 6 to 15 °F (day). If your temperature differential is bigger than 15°F, you’ll put your plant under stress. The sugars your plants have made during the light cycle will be poorly transported in the dark cycle, thus lowering growth rates.

Consequences of high temperature:
Small pores on the leaves (stomata) allow water vapour and gasses to leave the leaf and keep the plant cool (transpiration). If your plants are within their temperature ‘comfort zone’ and are transpiring healthily, they’ll keep themselves a few degrees cooler than the ambient air temperature. As a defence mechanism to conserve water, your plants’ stomata will start to close at around 85 °F.

With the stomata shut, your plants will not be able to transpire to keep themselves cool. If the temperature remains too high, the water trapped in your plants’ leaves can overheat, causing internal cell and enzyme damage. The result is poor growth and unhealthy plants.

If the temperature in your grow room is too high, your plants will respond in a few ways. They’ll appear stretched as the inter-node distance increases with a high temperature. This results in very airy flowers or poor fruit quality. During high temperatures, your plants will have difficultly laying down dense material because their sugar energy is being used so fast that they cut back on the energy used to make flowers and fruit. High heat is often associated with summer and low humidity in grow rooms. As a result, the roots of plants take more water than nutrient salts to compensate for the loss of water from the leaf due to high transpiration. This increases the nutrient strength in your reservoir or media leading to nutrient lockout, which can cause over-fertilization.

The time of day your lights come on can also have a big effect on your grow room temperature. In the hotter months, it’s advisable that you start the light cycle in the evening, running the lights through the night. This allows you to bring in cooler night time air into your room during the light cycle and avoids extreme mid-day temperatures.
(Running your lights through the night is great in Winter also, counteracting extreme low temperatures outside at night). If your grow room temperature is constantly high and growth is affected, you may want to invest in an air conditioner. Air conditioners are the most effective way to reduce high temperatures in the hotter months. They remove water from the air, thus lowering humidity. A humidifier may be needed when using air conditioning units.

Overlooked by many growers, Carbon Dioxide is vital for healthy plant growth. In fact, maintaining optimum levels of Carbon Dioxide can significantly improve the yield of your plants. 

CO2 or Carbon Dioxide is a colorless, odorless, and slightly acid-tasting gas, sometimes called carbonic acid gas, the molecule of which consists of one atom of carbon joined to two atoms of oxygen (CO2).

Without Carbon Dioxide your plants will not grow. This is because it’s essential for photosynthesis – the process by which your plants use Light, Water, and Carbon Dioxide to make glucose (plant food). Your plants need glucose for healthy growth. Photosynthesis can only take place in the light period. This is when the leaves of your plants
absorb Carbon Dioxide and give out Oxygen. During the hours of darkness, the leaves give off Carbon Dioxide and absorb Oxygen. At a higher temperature and light level, the absorption of Carbon Dioxide and the rate of photosy
thesis will also increase until a maximum is reached. Most growers are aware that optimum light and temperature can enhance plant growth. However, they are not often aware that even if optimum light and temperature are achieved, a lack of Carbon Dioxide can be a limiting factor – which means you will not get the best results from your plants.

in the atmosphere there’s about 300-400ppm of Carbon Dioxide. In a tight grow room with little/no ventilation the Carbon Dioxide present will not last long. If Carbon Dioxide runs out, your plants will stop photosynthesising, and eventually stop growing. To prevent such a situation, you need to ensure that there is an adequate amount of ventilation in your grow room By increasing the level of Carbon Dioxide to 1000-1500ppm during the light period, it is possible

We would recommend that you start adding Carbon Dioxide as soon as you put your plants into your chosen hydroponic system. You should continue adding Carbon Dioxide up until harvest. Never suddenly remove the extra Carbon Dioxide you are supplying to your plants. This can have an adverse effect on your plants’ overall development.