[Sticky] Cannabis Growers FAQ's

The ideal temperature for vegetative stage is around 26-28c (75-80f). But a couple degrees cooler during the flowering cycle

The best way to tell if your plants are ready for harvest is by checking the trichomes. These are the THC crystals on the buds of the cannabis plant.

Use a jewellers loupe, or magnifying glass to see the trichomes up close. All trichomes should be milky before chopping. But personal preference can be taken into consideration. See our guide on how to harvest a cannabis plant.

A big concern for new growers, and one of the most common Cannabis growers FAQs, is how to cover the smell of a cannabis plant.

By using a carbon filter, and good extraction, the air from your grow room will be "scrubbed" of smell, before being exhausted.

The average humidity level for growing cannabis is around 50% (40-60% range is fine). Humidity should be higher for young plants in vegetative growth stage, 60-70%.

When a cannabis plant is flowering, keep humidity between 45-55% to reduce the chances of mould spores germinating.

To calculate how big a fan you need, follow this equation:
Length x width x height of your grow room in meters. (This will give you the cubic capacity of your room)

Multiply that value by either 20 or 30 which is the minimum and maximum air changes required per hour for optimum ventilation. (30 air changes per hour are ideal for optimum ventilation).

For example: A grow room measuring 2mtrs x 2mtrs x 2mtrs = 8m³, x30 air changes an hour = 240m³ per hour will need to be extracted.

A 400-600w HID bulb, is a the standard amongst indoors growers, but you can also use LED and CFL lighting.

Choose which light will be best for your grow space, by reading our guide on grow lighting.

If you're not growing organically, then yes. Keeping the pH of your nutrient solution within the ideal range is crucial to healthy growth. It will help your plants to take up essential elements contained in the nutrient solution.

In hydroponic grow systems, the ideal range is between 5.8 -6.2. For coco growers, the pH tends to be kept at 5.8 during veg, and then 6.0 during flower.

For soil grown plants the ideal pH range is between 6.5 – 7.5, closer to 7.0 is optimum.

Ideally yes. It is possible to grow without an EC meter, but you will have no idea how strong the nutrient solution is. This can lead to excess nutrient feed problems which will harm your plants.

Measuring EC will also give you a good idea of how much your plants are eating. If you're using salt based nutrients, it would be highly recommended you use an EC meter to get the best diet to your plants.

Organic nutrients are not salt based, so will not be measured on an EC meter. Because of this, if you're growing organically, an EC is unnecessary.
Find out more about EC and how it works, here.

This is a one of the common Cannabis growers FAQs, but its hard to answer directly. The strength of your nutrient mix is very much dependant on the age, strain, and stage of the growth cycle of your cannabis plants. Experience will give you personal guidelines that suit your growing best.

General guidelines:

Young vegetative plants: Start off 0.2 points above your Background EC
Established vegetative plants: Should be around 0.8 EC, after gradually raising EC by 0.2 points, as the plants have grown.

Established flowering plants: Can be anything from 1.0 to 1.8 EC. Raise EC slowly, your plant will tell you when it's too much. If it's too strong, your plants will display signs of nutrient excess. In which case, lower the EC.

Your plants will suffer lock out, and nutrient excess problems. Also, plant growth will slow down, and visibly you will see, brown spots or curling leaves on your cannabis plant.

The plants will be weak and pale and yields will be lower. They will display signs of nutrient deficiency, and will be more susceptible to bugs, and disease

Hard water, is water from your supplier, that has a lot of dissolved minerals in it like Calcium, Magnesium and other trace elements.

This can cause pH instability and in some cases, will require the grower to use a hard water specific nutrient.

You can reduce the amount of trace elements and contaminates in your water by using a reverse osmosis system.

The ideal temperature for hydroponics nutrient solution is 18C. Lower temperatures cause a slowing in all aspects of growth, and higher temperatures will starve the solution of oxygen and can lead to root rot problems.

If your flowers look dead, with grey or brown patches, then you may have bud rot. To be sure, you can check out our guide on bud rot, or get a picture of the problem to us in our cannabis growers forum.

Keeping your grow room humidity below 55% during flower, and using plenty of fans will help to avoid this problem. But most gardeners will experience it at some point. Be extra vigilant in the last few weeks of flowering, and keep temperatures and humidity at ideal levels.

When growing cannabis hydroponically with a reservoir, you should change the nutrients solution every 7-9 days.

Two weeks should be the absolute maximum. If you do not change and clean the reservoir often, then a build up of salts left behind from the nutrient will cause serious problems for your plants.