There are few things you can do to fix a cannabis plant problem easily. Most of the time, a cannabis plant problem can be fixed, with in 24 hours. The most important thing to remember when treating cannabis plant problems, is take your time, and get the diagnosis right. If you get the wrong diagnosis, you could make the problem worse. Take your time, and ask for help in the forum if you need it.
Most problems with a cannabis plant are caused by the same few things. In this guide we will cover the most common causes of cannabis plant problems, and how to fix them. After reading this guide, you should be able to keep your plants at full health throughout the grow.
7 Steps to Fixing any Cannabis Plant Problem
- Temperature & Humidity
- Provide Enough Light
- EC and PH Levels
- Breeze & Air Circulation
- Maintain Healthy Roots
- Prevent Bugs & Mold
- Ask for Help
Temperatures and humidity in your grow room will influence what your plants will eat and drink. If the environment is not at optimal levels, serious problems can occur. Having your grow room at optimal temperatures will have your plant grow happier and healthier. Too hot, or too cold, and the plant can shutdown and stop growing. In extreme circumstances, your plant could die.
Also, if the grow room is too humid, your plant will not be able to breathe. Your plant needs to be able to evaporate moisture from the leaves into the air. The more humid the air is, the harder it will be for that moisture to evaporate.
Grow Room is too Cold
When a cannabis plant starts to fall below the temperatures of 18c, its metabolism will slow down. This will slow down its growth. As temperatures get colder, the metabolism slows down further. Once the temperatures reach below 15c, your plants cant shut down completely. Temperatures below 10-12c, maybe even be cold enough to kill a cannabis plant!
Also, because it is cold, the plant will stop drinking so much, and this may lead to water logged medium, or ph and ec fluctuations in hydro. Even when lights are off, try to keep temperatures above 20c. With the best temperatures being around 26c.
The most common type of heater in small grow room are “oil rads”. These are radiators that are plugged in, and then a heating elements heats oil inside. This is an efficient way to bring heat into the grow room
Grow Room is too hot
If temperatures reach above 28c in your grow room, your plant can start to suffer with heat stress. The symptoms of this are when the edges of the leaves cup upwards. This is called “canoeing”.
Because of the extra heat, your plant will be forced to drink more, to try to cool itself down. This will result in more water being used, and evaporated. This can cause a “EC Spike” in the medium. EC spikes will cause nutrient burn and other cannabis plant problem you don’t want.
You must have adequate extraction in your grow room to remove heat, and moisture from the air. If the ambient temperatures outside of the grow room are causing problems, than air conditioning will be your only option.
Some strains of cannabis are more hardy than others. Some like temperatures up to 32c, some do not. Each strain is different. If you see the symptoms of heat stress, like canoeing leaves, you need to reduce the temperatures in the grow room
Lowering Humidity in Grow Room
Warm air will hold more moisture than cold air, so with a raise of temperature usually comes arise in humidity. Keeping humidity level low, especially during late flower is crucial to keeping a plant mould free. There are a few ways to decrease the humidity of your grow room:
- Add more intake Vents: Increase the amount of air that can be pulled into the grow room, this will increase extraction rate. Maybe consider active intake.
- Bring more fresh Air into the grow room: The grow room needs to pull air from a good fresh source. Open windows, and doors, to allow more fresh air into the room
- Buy a GOOD dehumidifier: By good, we mean 16l +. A small dehumidifier will do very little, you need a big one.
Raise Humidity in your Grow room
If the humidity of your grow room is too low, the moisture in the plants, will evaporate too quickly. This will cause leaves to dry out, and become fragile. Also, if the plant drinks too much there will be an EC spike in the medium. Keep humidity at the level recommended for each stage of plant growth. You can do this by:
- Add moisture to the air: By using wet towels hung in the grow room, you can increase the moisture content of the air. It will work but not for long
- Decrease extraction: Slowing down extraction will reduce the amount of air being pulled out of the grow room. Also temperatures will rise too, which will allow the air to hold onto more moisture.
- Buy a humidifier: You need proper equipment to grow good cannabis. Invest in a humidifier so you can have more control over your grow room environment.
You can easily fix a cannabis plant problem by maintaining a steady, consistent environment in the grow room. With the right temperatures, and correct humidity level for the stage of growth, your plant will be happy. What you need to do now, is make sure they are getting enough light.
Providing Enough Light to a Cannabis Plant
Sometimes, health problems can be caused by lack of light, your plants will use light to make food, and if they do not have enough, they can not eat as much as they would like. Providing a sufficient amount of light to your cannabis plant will improve growth rate, and overall health of your plants.
Hid Lighting: If you’re using HID lighting, a good rate to go by is, 50w of light, per square foot of grow space. Remember, the bigger bulb you use, the more heat will be produced. Make sure you have adequate extraction for your grow room.
LED: Lighting: Growing with LED lights is more efficient than using HID. For growers using LEDS, 30-35w per square foot is recommended. Always keep your lights at least 18 inches/ 40 cm away from the top of your plants.
Lights too Close to Cannabis Plants
If you’re light are too close to your plants, it can cause “Light Burn”. This is when the heat from the light cause white, or orange patches at the very tops of your plants. If this is happening raise the height of your light straight away.
Here are some picture to help estimate of how high to hang your lights above your plants.
Lights Too far Away
When your plants are too far away from your light, or not receiving enough light, you will see them stretch. They do this to try and get closer to the light, as the closer they are the stronger it is, and they need that light to make food. When your plants stretches for the light, it will cause weak stems, and long internodal spacing.
EC Levels for Cannabis Plants
This will apply more to grows that are using salt based nutrients rather than organics. If you are growing organically, the fix won’t be as simple. See our plant problems guide or ask for help in our cannabis growing forum to fix a cannabis plant problem in organic mediums.Head to the organics section to find out how to fix a cannabis plant problem with organic nutrients.
EC is the measurement of how much food is in your water. By measuring EC you can determine how much your plant is eating, and if you should feed more or less.
A common problem for growers is they feed their plants too much, and suffer with nutrient excess issues. By following the EC of your reservoir, or run off, you can see if your plant is eating properly.
If the EC of the run off, is coming out lower than what your feeding, your plant could be hungry, and raising the EC might be a good idea.
If the EC of the runoff is coming out higher then the EC going in, then your feeding the plant too much. Reduce the EC for your next feed.
For an easy to follow EC and PH chart for hydroponic reservoirs, print or download these picture guides:
Correct PH Levels for Cannabis Plants
PH is vital to the nutritional intake of your plant. If the pH is out of range the plant can’t eat the elements it needs for growth. Measure the PH of your reservoir, or the run off after feeding your plants. (Make sure it is as the water is still flowing, out of the pots for best results).
The PH for hydroponics setups, and coco like mediums, should be around 5.8-6.2.
When growing in soils, the ph should be around 6.5-7.0. Most soil will be treated with a ph buffer, like dolomite lime. This will help keep the pH of your soil at the right levels. So there is less need to monitor the PH.
4) Breeze & Air Circulation
Your plant need fresh air in the grow tent. This is not only because heat and humidity needs to be removed, but fresh levels of CO2, oxygen and other elements in the air need replacing. Even if temperature and humidity is fine without it, you still need good extraction to allow your plant to breathe fresh air.
Correct air exchange rate: To calculate the size extraction you need, follow this calculation:
Step 1 – Length x Width x Height of growing area.
For example, a room that is:
8′ x 8′ x 8′ will have a volume of 512 cubic feet.
Step 2 – Cubic Feet per Minute Required
The fan should be able to exchange the air in a grow room once every three minutes, or at least 20 times an hour. Therefore:
512 cubic feet/ 3 minutes = 171 Cubic Feet per Minute.
This will be the minimum CFM needed for the air exchange in your grow room.
The maximum amount of extraction you should use will exchange the air in the grow room every two minutes, or 30 times an hour. Using the calculation above, ( 512 CF/ 2 minutes = 256 CFM) you can find what extraction is best for your grow space.
Fans for air movement
Air needs to be kept moving around the grow room at all times, you need good, reliable fans that are not going to break down. There are many options for you here. You don’t need anything special
A usual desktop fans will do fine, but most growers prefer using clip on fans, as these will not take up any floor space in the grow room.
Another good type of fan, is a bladeless fan like a dyson AM02 tower fan. Theres is a wider spread of air, and there are no blades to accidentally chop leaves, and gather dust.
It is good to have 2-3 fans for every square meter of grow space. They must be oscillating fans. A constant draft can cause fan burn on your leaves. Fans must stay on 24/7! Never let them turn off for too long, mould spores will germinate in stale air pockets and ruin your crop.
Your plant will pull the vast majority of nutrients it needs through the roots. If your roots are unhealthy, your plants will be too. To keep the root zone healthy, you must allow plenty of air to get to the roots.
In soils, you must let the medium dry out until the pot feels light, and the top inch of soil is dry. If you water your plants too much. the root zone will not be able to draw in fresh oxygen, and the root zone will begin to suffer.
This is a common problem for new grower. It is assumed that the more a plant can drink, the more it can eat. Which is true to some extent but, the roots also need air. If there is too much water, the medium will be waterlogged, and fresh air can not be pulled to the root zone.
Bad bacteria can breed in situations like this, and you will soon find rot setting into your roots.
To prevent this, let your medium dry out in between feedings if you’re growing in soil. Coco is a little different is it light and airy, and has great drainage, so it is hard to over water in coco.
But if you’re growing in full hydroponics systems, then check to make sure your air stones are working properly, and are not tangled in the roots.
Droughts in the root zone.
Without water, nutrients can not be moved around the plant, the plant can’t sweat, and it will soon die. This is obvious, but what isn’t so obvious is what goes on in the root zone.
When the medium dries out too much, good bacteria begin to die. Also, the roots will begin to die back and air prune. If your plants are starting to wilt, and leaves are drooping, it may be down to a need of water. Feel the weight of the pot, and check the top of the medium for dampness.
There is some evidence to suggest however, that in the last couple of weeks of the flowering cycle, you should give your plant one long drought. This will encourage the plant to push out more resins and terpenes.
6) Bugs / Mould
Along with all of the previous mentioned potential issues, you can get outside invaders into your grow room. Certain bugs can devastate a whole crop in a matter of days. You must act quickly and accordingly if you suspect them.
If you have seen or suspect bugs on your cannabis plant, your first step, is to identify which bugs it is. You can usually tell this by looking at what kind of marks are left on the leaves, or you may see some of them on the plant.
Treating bug infestation on cannabis plants is fine during veg, as you can use pesticides and sprays to get rid of them. But during flower, especially late into flower, you do not want to spray your buds with anything, never mind chemicals.
You can use Predatory insects to kill most pests during flower. These bugs will only eat the living bugs on your plant. This will help reduce the number and can even kill of any bug problems.
Bud Rot is something that will set in days or even weeks before you see it. Mould spores are everywhere, all the time, they are like seeds. Given the right conditions these spores will germinate, and grow.
If you have found rot, there is nothing you can do, do not use the bud to make oils or hash, it must be composted, or thrown in the bin. The only thing you can do, is prevent the infection from getting worse.
Turn off all fans immediately if you have found rot. The mould spores will travel in the breeze, and you need to reduce the risk of it spreading. Cover the infected bud with a plastic bag, and remove the whole cola.
Check your whole crop thoroughly for more, and when you think you have it all, reduce your humidity! Mould spores will germinate above 55% humidity, and below 15c. Most germination happens during lights off.
Add a heater to your grow room that can be turned on while lights are off. Also, consider buying a dehumidifier if levels are a constant issue, it will be worth it when it saves your future crops!
Do not rush anything when trying to fix a cannabis plant problem, always look for a second opinion if you need help! Giving your plants incorrect treatment can just make things worse. So take your time to get it right, you have 24 hours from first diagnosis of most thing to react.
Take this time to research and resource what you need. Find the info and tools you need to fix a cannabis plant problems. By signing up to our forum, you will have access to many experienced growers that can help you along the way.
We have all been there before, and we understand your frustration when your plants get ill. We can help, and it would be a pleasure to have you in our community.
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