The Basics Of Indoor Environment Control

Quit Marijuana The Complete Guide

New Treatment for Cannabis Dependence

Get Instant Access

By now you have managed to set up the basic environment in which your indoor plant will grow. As a gardener you have total control over that environment and need to make sure that it meets your plants needs.


As your plant grows through its life cycle it begins to absorb some of the minerals from the soil. When it does remove minerals it adds some waste material of its own. We have said before that Cannabis plants like a steady pH of around 7. The removal of nutrients and addition of waste material on top of other factors may cause this pH to increase or decrease.


It is always good to check the pH at least once every week for plants that grow in soil. It is also good to check the soils pH a day or two after you feed your plant. A pH test kit can be purchased in most grow shops. The electronic test kits can be a bit expensive though. If you find that your soil's pH has shifted out of the 6 - 8 range you may want to try and bring the pH back to 7. Again, below 7 is acidic and above 7 is alkaline. There are two ways to do adjust the ph of the soil. The first is called a soil flush and is not recommended but may be needed under certain circumstances such as serious pH fluctuations and chemical burns.


A soil flush is a last resort 'time to save our dying plant' manoeuvre. You only resort to a soil flush when all else has failed. Let us pretend for a moment that you have a soil that holds a lot of water and you want to feed your plant. You take out your favourite feeding bottle and you decide that you want to add it straight to your plant and then pour water in after. This is never recommended! Always mix your food with water in a container and then use the container on your plant, such as a jug or watering can. Try follow the guidelines on the feeding bottle along with the recommendations in the book. If not the following story may happen! So you open the cap and bend it over towards the soil. You flinch, the bottle spills. The next thing you know half of your raw feeding liquid has managed to find it's way into the soil. You curse yourself that you did not follow the instructions. You grab your hair, AWhat to do?' you say. You pick up this book and turn to this chapter. You read about the soil flush and see that your plant now has a small chance of survival. You know that all the raw chemicals will kill your plant. All hope is lost. This is your last resort. Here is how to flush your soil.


(2) Turn the plant on its side making sure that you do not break the stem!

(3) If you think the stem will break then quickly find a long stick and place it in the soil.

(4) Use a piece of sowing thread to tie the plant to the stick at several points. (5) Tape the stick to the pot. (6) Tilt the plant on its side so that the top of the pot with the soil is facing at an angle towards the sink.

(7) Watch the colour of the liquid that runs out.

(8) Do this until all the liquid has poured through.



(1) Pull your plant back up and sit it in the sink. Pour lots of water on top of the soil.

(2) Wait until the water flows out the bottom of the pot. Look at the colour of the flow.

(3) Repeat this process until the colour of the water becomes clearer. (The soil should get very muddy when you do this and some of the mud will pass out with the water.)

(4) Once the water is clear tilt your plant on its side again and wait for all the water to drain out. You may repeat this process several times. If your feeding solution does not have a colour then you should keep an eye on the texture and smell of the solution that you are flushing out. When this changes your flush has worked.

(5) Quickly take your plant to a warm dry area and wait for the soil to dry out.

(6) Use a pH meter to test the pH of your soil.



(1) You can use a screwdriver to make holes in your pot if it is light and the plastic is not tough. You can always use thick masking tape later to patch the holes closed. If you can do this then do and follow step B. (2) If you can not then you need to do an emergency transplant.

(3) Quickly set up a new pot and put in new soil leaving a large gap in the middle where your plant will go in.

(4) Take your plant and use a knife to cut around the edge of the soil as close to the rim of the pot as possible. Go as deep as you can. (5) Put you fingers in down around the inside of the rim and pull the plant out of the pot.

Try not to rip the roots.

(6) Hold the soil over the sink and place it down near the drain holding it together with your hands. If your root mass is big you may need help doing this.

(7) Turn on the water and let it run slowly down over the soil.

(8) Keep holding the plant for a number of minutes until you see a change in the water that is coming out from the soil. Do not crush the soil just hold it. It will get muddy and it will break up a bit, but this is to be expected.

(9) When the water changes quickly place the plant into the new pot.

(10) Fill up the spaces with new soil and use a stick to prop up your plant if needed.

(11) Quickly take your plant to a warm dry area and wait for the soil to dry out.


(1) Every day measure the pH of the soil. If you have flushed your plant properly it should return to the near 7 mark (given that the water you use is a neutral pH of 7). In the meantime you can be reading about how to change your plant's pH as directed below.

It is sad to say but very few plants do survive such an emergency soil flush. The soil flush is, in its essence, over-watering your plant to the point of removing most of the minerals and ingredients in the soil. If your plant manages to pull through you have done well. If your plant does not then you will know better next time. A soil flush causes the plant a great deal of shock and should only be attempted as a last resort if your plant is dying and can not be cured by any other means.

If your plant makes it, the plant may have sustained some damage. If any of the leaves are burnt or look dead you can remove them from the plant by clipping them away. Plants usually take about 2 weeks to get back to full health.

pH - bringing back to neutral from acidic:

If the pH of your soil is too acidic then you may want to bring it back to a natural 7. What you need is Lime. Lime can be bought in small containers from any grow shops. Just simply add some lime to your soil the next time you water your plant. Only add small amounts each time and then the next day use the pH

meter to study the effects. What you will find is that you will get to know your soil better than I could describe here and know what it needs. Advanced growers know how much lime they need to bump their acidic soil back to 7. They know this by trial and error. This is one thing about cannabis growing. The best cannabis growers grow good cannabis because they have made many mistakes in the past. Learning is an experience and that is why people enjoy growing. They like to learn more and experience more. Don't let a bad growing encounter put you off.

pH - bringing back to neutral from Alkaline:

If the pH of your soil is too alkaline then you may want to bring it back to a natural 7. To correct this you need to make your soil more acidic. Here is a list of ingredients that can each be used to return your plants PH to 7.

-Cottonseed meal -Lemon peels -Ground coffee

-Some Fertilizers also are very acidic and can bring the pH down to 7.

When using this method always moderately apply the substance and check the pH. Over time you will know what measures to use. This is best left up to the grower as he/she will know how big their pot is and how much should be added. Experiment a bit and learn as you go along.

These products are available in most grow shops. They actually act as a pH agent for adjusting your soil pH. They only come in two forms - pH up and pH down. More and more people are using these chemicals to adjust their soil pH.


Remember NPK? Well, NPK are the primary ingredients that are needed in soil for marijuana to grow well. NPK stands for Nitrogen, Phosphorus and Potassium. In addition to these there is something called secondary supplements. Secondary supplements are found within the soil but sometimes not all of them are there. The secondary supplements are as follows. Ca (calcium), Mg (magnesium), and S (sulphur). CaMgS for short. There are also seven more micronutrients. These are as follows: iron, boron, chlorine, manganese, copper, zinc, and molybdenum.

These micronutrients are not extremely important for good plant health, but the secondary nutrients and Primary nutrients are. Check your bag to see if it has some secondary nutrients.

Sometimes a Ca, Mg, or S deficiency in the soil may cause growing problems for your plant. If the soil is lacking one of these factors your plant may start to display a nutrient deficiency. Mg problems are common. To correct this feed your plant a 1/3 of a spoon full of Epsom salts per 3 gallons of water every 3 - 4 weeks.

If your soil does not have these properties and you feel that you are going to have future problems then simply find a feeding product that contains these elements. Next time you feed your plant you will be able to supplement it with these missing secondary nutrients.

Micronutrient problems rarely show themselves unless there is a problem with lockout. Lockout is a chemical reaction that takes place among the nutrients in the soil. It can occur if a large amount of one single nutrient is added. This can lockout the other nutrients, preventing your plant from using them. If lockout does occur then you need to flush your soil.


Feeding is the process of adding to your soil what the plant has taken out. You will only need 3 types of feeding solutions throughout your plants growth. You will need a bottle of feed where the NPK has equal or higher levels of N than P and K and you will also need a bottle that has higher levels of P than N and K. The first one is to be used during vegetative growth and the second is for flowering. You will also need a third bottle of secondary nutrients.

You should only feed your plants when they need it. The amount of feeds that you will use is relative to your growing conditions and strain. Most plants only need to be feed every fortnight at 50% or less than what it says on the label. Marijuana plants burn easily. So never mix your solution at 100%. If it says use 1 cap full of feed per 3 gallons of water, then use 1 cap full per 6 gallons of water. Sometimes you might even end up burning them using these low levels. This goes for both flowering, secondary nutrients and veg feeds. You should never have to feed cannabis plants once a day. During flowering simply switch the feeding bottle over to the one with the NPK where P has higher levels than N and K. You may want to add secondary nutrients once every 3 weeks to your grow. Epsom salts is a great way of giving your plant Mg, which is probably the most important secondary nutrient.

During vegetative growth and flowering, cannabis plants love to get fresh air. Always keep a window open and let your grow room refresh itself every day. The fresher the air the better. Also during the dry periods, in between watering, the roots like to breathe. Fresh air is always the best air. During winter you may want to reduce the time you leave the windows open as the cold may stunt growth. Just refresh the air in your room for 15 - 20 minutes during winter and close it again.

If your grow is enclosed, then use fans to extract the old air and another fan intake to refresh the system.


Cannabis plants work best in the 40 - 80 percent relative humidity area. rH (relative humidity) is the amount of water in the air. Fresh air always is the best way to control humidity. If you have a rH measuring kit you can judge for yourself how much fresh air you need before hitting the optimum 60% level.

There are some expensive devices called De-humidifiers that control humidity in the room. This is not recommended unless you have a very large grow area underway. Just use fresh air and you can't go wrong.


Temperature is controlled by any heating unit or natural sunlight that your room receives. Normal households have suitable temperatures for growing cannabis in. The best meter for temperature control is the human body. If you find it is too cold in your grow room then so will your plants. 75 degrees Fahrenheit is what you should aim for. Slightly warmer rooms do help plants to grow a bit quicker. Use a thermometer to analyse your room's temperature. If too cold, turn on the heating. If too hot, open a window and maybe even use a fan.


Plants enjoy C02 and release O2 during a process called photosynthesis, but more 02 is released than C02. Since our plants would like more C02, the grower can use a C02 generator to help the plants growth. C02 also helps grow bigger buds! Since room C02 levels in general are low the plants can use a bit more.


Figure 5.27 - This is a regular squirrel cage fan. These fans come in all sizes and can be bought in most hardware stores.

Figure 5.27 - This is a regular squirrel cage fan. These fans come in all sizes and can be bought in most hardware stores.

Fans can be placed quite close to mature marijuana plants. Cannabis plants like the wind if it is a slight breeze because it helps them to develop stronger stems and branches. Also fans circulate the air around your plants.

Fans help create an environment which makes the plant think that it is outdoors. Get a fan if you can. It is worth it and will help you grow a better plant!

Was this article helpful?

0 0
Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

Get My Free Ebook

Post a comment