Today we have an article from the Rand corporation, a study on the effects of mixing Cannabis and Tobacco use in young adults.
More than a third of young adults report using both cannabis and tobacco or nicotine products, providing a unique challenge to public health officials as cannabis is legalized in more jurisdictions, according to a new RAND Corporation study.
Studying a group of young adults from California, researchers examined the many different ways that cannabis and tobacco or nicotine products are used together—a by-product of the introduction of new vaping devices and other delivery methods.
Among those surveyed, young adults who used cannabis and tobacco or nicotine together in some way (either using one right after the other or by mixing the products together) tended to consume more marijuana and tobacco or nicotine products, and report poorer functioning and more problematic behaviours compared to those who did not use both products together. The study is published online by the journal Psychology of Addictive Behaviours.
“There is growing concern that as more states legalize marijuana, there also will be an increase in tobacco use because the two substances may be used together,” said Joan Tucker, lead author of the study and a senior behavioural scientist at RAND, a non-profit research organization. “Co-use of cannabis and tobacco could reverse some of the progress made on reducing rates of tobacco use.”
Mixing cannabis and tobacco is more common in some other countries compared to the U.S. But in recent years, cannabis and tobacco or nicotine co-use in the U.S. has risen among adults, coinciding with greater availability and diversity of cannabis, tobacco and vaping products. In the U.S., national data show that young adults between the ages of 18 and 25 are more likely to use cannabis, tobacco or nicotine products than any other age group.
Studies on the issue thus far have been limited in scope. They typically have not accounted for the use of newer vaping products nor examined whether certain ways of co-using these substances is associated with greater problems.
RAND researchers surveyed more than 2,400 young adults during 2017 and 2018. Participants have taken part in an ongoing study of substance use patterns from adolescence to young adulthood. While they originally were recruited in 2008 from 16 middle schools across Southern California, they now live in more than 400 neighbourhoods throughout the state.
Among the young adults in the RAND survey, about half reported using cannabis during the past year, and 43% reported using some type of tobacco or nicotine product during the same period. About 37% reported co-use of the substances at some point during the past year. More than 80% of the young adults who reported past-year marijuana use also reported past-year tobacco use.
Using both substances sequentially (one right after the other) on the same occasion was reported by 17% of the young adults, and 14% reported using the substances together by mixing them in the same device.
The study found that co-use of cannabis and tobacco or nicotine is associated with worse functioning, including poorer mental and physical health, as well as greater problematic behaviours such as fighting, skipping school, being fired and getting in trouble with the police.
Young adults who used both products in the past year, but did not use them on the same occasion, did not show greater risk compared to those who used only one of these products.
“How these products are used together matters in terms of potential health consequences and functioning among people in their late teens and early 20s,” Tucker said. “Our findings suggest that we can no longer just think about the consequences of tobacco use or marijuana use alone—we have to think about them together.”
For example, programs designed to educate people about the health risks of tobacco or cannabis probably need to address both substances at the same time, Tucker said.
Support for the study was provided by the California Tobacco-Related Disease Research Grants Program Office of the University of California and the National Institute of Alcohol Abuse and Alcoholism. Other authors of the study are Eric Pedersen, Rachana Seelam, Michael Dunbar, Regina Shih and Elizabeth D'Amico.
In order to talk about humic acids and what they do for plants and growing substrates, we must first talk about humus.
If we analyze top soil for example, there is 45% mineral content 50% air & water content, 2% plant & animal remains, 2% Humus and less than 1% living organisms (bacteria, fungi & insects).
The formation of humus is a continuous cycle, breaking organic matter down into basic components by the decomposers, insects, fungi and bacteria.
Decomposition is continuous, alongside it, is the slow degradation of rocks and minerals caused by external factors like natural weathering and rock eating organisms named lithotrophs.
The second part of this cycle is the reformation of the broken down particles into a variety of chemical compounds, collectively these compounds are called humus. Eventually these compounds break down further into molecules that are very chemically stable and resistant to further decay.
These molecules are broken down into three forms;
Now that we have a basic understanding of the origin of humic acids we can now we can talk about their relationship with plants. Humic acids contain high amounts of carbon which directly feeds microbes, in turn improving soil ecology.
Humic acids benefit gardeners because they act as a natural chelator of other elements.
“Chelate” Allows complex molecules to bind to other ions.
Molecules of humic acids are negatively charged because they have lost positively charged hydrogen ions, this creates spaces on the molecules where positively charged particles, zinc, iron, copper & manganese can attach. The roots systems of plants are also negatively charged but have a much greater charge than humic acids do, as a result the humic acid compound is drawn to the root, positively charged ions then leave the humic acid molecule in favour of the root. The plant in turn can now use these micro elements for growth and reproduction.
Positively charged ions are referred to as cat-ions, is the measurement of a substrates ability to hold onto these cations, this process is called cation exchange capacity (CEC), mineral composition of soils is made up of various combinations of sand, silt & clay. Clay particles have a strong negative charge, soils comprised with large amounts of clay have a high CEC, which reduces leaching of the positively charged cations. Sandy soils have a low CEC meaning some elements are more easily flushed through the roots zone, because of humic acids ability to chelate cations, humic acids may have the ability to raise the CEC of soils and other substrates, allowing more readily available elements available to the plant, in turn making fertilizer applications more efficient, for this reason it is advised that you incorporate humic acids into your fertilizer regime.
References: ecofarm, Omnia nutrition, Down to earth ferts
Note: To be able to read PPFD or instantaneous PPFD will require an accurate quantum meter to take the readings, such as the Apogee MQ-500.
Most light meters measure the instantaneous photosynthetic photon flux density in µmol m-2 s-1 and yet plant growth is determined by the integrated daily photosynthetic photon flux density in mol m-2 d-1.
Here is how to convert from µmol m-2 s-1 to mol m-2 d-1 when using electric lights.
There are 3600 seconds in an hour. If the electric light output is constant, the instantaneous PPFD can be added up (integrated) over an hour.
Therefore 1 µmol m-2 s-1 = 3600 µmol m-2 h-1.
This must be divided by a million (1,000,000) to convert from micromoles to moles: 3600 µmol m-2 h-1 = 0.0036 mol m-2 h-1.
If the electric lights are on continuously (24 hours), the hourly PPFD must be multiplied by 24 to get the daily PPFD: 0.0036 mol m-2 h-1 = 0.0864 mol m-2 d-1.
There are 86,400 seconds in a day (3600 x 24 hours) so the daily PPFD can be calculated directly from the instantaneous PPFD from the following equation: µmol m-2 s-1 multiplied by 86,400 and divided by 1,000,000 = mol m-2 d-1.
So: 1 µmol m-2 s-1 = 0.0864 mol m-2 d-1 with continuous light
These conversions are accurate only under electric lights. The integrated daily PPFD from sunlight changes during the day so a single measurement cannot be used to estimate daily PPFD.
Daily PPFD Reference Table
Instantaneous PPFD (µmol m-2 s-1)
Daily PPFD (mol m-2 d-1)
Instantaneous PPFD (µmol m-2 s-1)
Daily PPFD (mol m-2 d-1)
Instantaneous PPFD (µmol m-2 s-1)
Daily PPFD (mol m-2 d-1)
*There are 50 to 60 moles per m2 day on sunny summer days in outside areas without any shade.
When your lights turn off what happens is the temperatures start dropping and the root zone activity slows down, when the temperatures reach below 15C degrees the plant's metabolism will shut down causing stunted growth and restricted nutrient uptake which can display some potential deficiencies with new growth.
If your grow room is reliant on ambient conditions you will find this is a major issue and without corrective action, your plants will go downhill very quick. You cannot ignore the minimum requirements.
Below 15 degrees and its full shutdown, every night!
What should my temp be at night?
18.5 -21.5 is the perfect range for the environment and the root zone.
What can I do to raise my temperatures?
Most hobbyists employ an oil (column/bar) heater, these units come prebuilt with thermostat controllers which will allow you to maintain a minimum and a maximum temperature during lights off, they are reasonably priced but do consume a fair bit of power.
Climate control units offer cooling and heating features but come at a significant cost and they can consume some serious power. Proper HVAC systems are the best way to control your environment temperatures but are not always an option, depending on the location of your grow room or grow budget.
Seahawk have a range of various sized Heat mats these will also raise the ambience by 10 degrees however only ideal during the propagation phases, although I have seen some growers wrap their fabric pots with heat mats during the night, so an idea worth considering.
What will happen if I do not correct my temperature?
If you do not correct your temperature, it will only be a matter of time before the plant starts to wilt and die. As a generalisation; the warmer the environment, the faster plants grow, the colder the environment, the slower plants grow.
The science is solid on temperature and plant growth, so rather than formulating wild theories about what could be causing problems, just set it up from the beginning, then it will never be a concern, and going forward you will only need to adjust your environment as the seasons change.
Please note: The temperatures listed in this tutorial are optimal temperatures to aim for to achieve the best conditions for your plants. Do not panic if your temperatures are outside of these ranges for periods of the day, simply aim for these ranges for the best results.
It is quite cold outside at the moment, so in this article, we explain how important temperatures are for each stage of growing.
Let’s start from the beginning:
Seed Germination: 24-27°C - 75.2-80.6°F
Seed Germination is an essential part of the plants life, if temperatures fluctuate and don’t remain consistent temperatures your seedling will struggle and will not have a ‘perfect’ start to life which will affect: Growth rates, Plants overall health and overall end yield.
Clones or Cuttings: 24-26°C - 75.2-78.8°F
Clones or cuttings require the same temperature as seedlings.
25 °C - 77°F is perfect for all varieties, allowing your cuttings to root much faster than colder/warmer or unstable fluctuating temperatures.
Vegetating/growth: 23-29.5°C - 73.4-85.1°F
Vegetating plants grow very fast in the right conditions, there is a big difference in this phase due to different expressions in characteristics.
If you are after a the ‘colour fade’ harvest pushing the temperatures lower will help your specific outcome (Keep in mind not every variety will change colour)
If you are growing a longer flowering variety then they require slightly more heat due to them originally coming from around the equator where it is much warmer so we would grow these specific varieties at around 27 °C - 80.6°F.
If you are growing an 8 week strain optimum temperatures are closer to 25 °C -27°F due to the strain originating further from the equator.
Flowering/bloom: 22-28°C - 71.6-82.4°F
As we transition our plants into the flowering/fruiting phase of their life cycle, the temperatures should roughly stay similar to the vegetive period depending on your variety and the outcome you are trying to achieve.
If you are growing a longer flowering variety, starting flower at 25 °C - 77°F and ending closer to 28 °C – 82.4°F is ideal.
Drying: 18-21°C - 64.4-68°F
If your room temperatures are too high your flowers will be significantly less potent and much less aromatic.
Consistent temperature stability in the drying phase is what we call a ‘slow dry’ and is much better in my opinion for holding all the essential oils inside the flower.
Too fast of a dry and your flowers will be more crispy/crumbly much less potent and less aromatic. Dry at these temperatures for 4-14 days depending on flower structure and size.
Curing/storing: 18-21°C - 64.4-68°F
Once you are this stage, make sure your flowers are dry and the stems snap or rapture when bent, because if you start curing with dampish bud you will have mould in no time. Keep at a consistent temperature with burping your jars (opening removing old air) for the first 2 weeks after this time the flowers will be much browner and from here your smell and taste of your flowering will majorly increase.
Stay tuned for next week's tutorial, we look at night temperatures and how they will affect your plants.
A great question, the amount we water/feed our plants is different for each growing medium used.
The amount of water/food we use is subjective to the size of the pot being used.
The frequency of water/food being applied is dependent on a few things, specifically consumption, have they started to suck the pot dry or are they sitting in a soggy pot not really doing much?
In this topic we discuss the most commonly used growing medium and the most commonly applied watering/feeding techniques, and more importantly what you can do in these situations if something isn’t going to plan. This tutorial is based on RTW, this doesn’t negate flushing if there is a problem.
Coco Coir, Coco Perlite & Coco Clay mixes
Coco is not soil, therefore we cannot treat it like soil. Coco needs to be kept moist pretty much all the time. If coco dries out too much it actually inhibits the spread of root growth.
This seems to be a confusing topic for new gardeners so let’s break things down a little, firstly lets pick a method of feeding for this example I will use run-to-waste as the feeding method.
Everything is relative to growth and pot size!
100mm Pots, usually house seedlings for the first 2-3 weeks before transplanting into the next size pot up.
Now, a 100mm pot is not going to consume much food each day, but it does require food each day. The idea here is to ‘micro-feed” to help the plants root system develop which in turn will require greater amounts of food as it grows (transportation).
Run to waste (RTW) merely indicates that upon feeding a solution there is a small amount of run off, this tells the grower that the medium has been soaked effectively, not drowned.
A seedling sitting in a soggy pot will do nothing, and even more so if your environmental temperature is not on point, in the right conditions with the right feeding application consumption is non-stop.
So how much is too much? Let’s look at the process: (If temperature is not on point, please refer to the temperature blog for more in-depth environmental information)
New seedling alive.
Transplant to new pot with coco (100mm)
Make up 1L of water and add 0.5-1ml of the supplied Rooting solution
Gently water in approx. 300ml-400ml until the newly transplanted seedling is saturated thoroughly.
EVERY day after we will micro-feed them with the same dosage of food per L, the major difference here from the first flooding, is the feeds are now approx. 50-120ml. this dose will roughly achieve similar run off to the first feed.
Repeat this each day, until the new feeding week comes around so that on day 8 (week 2 day 1) you will make up a newer solution with a slightly increased amount of food and repeat the steps, what you should start to notice is the volume of solution slightly increasing which is the indication the plant is up taking the food that’s going in.
When your plants have a large enough root system and can consume food rapidly it is then time to transplant into the next size pot. Repeating all the steps from above the only thing that is changing is the volume of solution going in.
During the vegetation phase all established plants require daily feeding, its coco, not soil remember that! Figuring out how many times your plants need feeding is solely reliant on you as the gardener to understand and organize, but most commonly in veg most gardeners who RTW would feed 1-2 times per day during the 18 hour cycle.
Feeding a flowering plant does involve a lot more work and interaction, the premise is still the same though, every day we must feed them.
The frequency of feeding for flowering crops is again subjective to pot size and volume of solution etc. but commonly between 1-4 feeds per day in a RTW style grow. Remember that the first 2 weeks of flowering is the plant translocating the sugars formed in the vegetation phase so you will find that the volume of solution required at the first 2 weeks of flowering is much greater, then consumption slows for about 2 weeks (meaning you can drop to 1-2 feeds per day) then when your plant has transitioned to full flower there is another 2-3 week period where the consumption for food goes through the roof.
Feeding is generally subjective to your environment and conditions. Everything is a guide, each plant is unique like a fingerprint, so sometimes you “The gardener” have to understand this, and use your intuition.
Einstein once said:
“The definition of insanity is doing the same thing over and over again and expecting different results.”
They are a part of the Mycetophilidae and Sciaridae super families. They feed on decaying organic matter, fungi and plant roots (which contain the nutrients you feed the plants) they cause significant damage to the root-zone as the larvae attach themselves to the root feeders and deplete them of nutrients in turn feeding themselves whilst starving the plant.
They can also carry diseases such as Pythium on their feet and transfer it from plant to plant.
Many growers who correct this problem long term, report yield increases of approx. 15-25%, that’s literally how much food they are draining away from the plant.
There life span consists of about 3-4 weeks depending on the conditions on the environment. They love damp moist (overwatered) mediums, they breed insanely in these conditions (up to 300 eggs in an adult’s life) they also love high humidity air.
Fungus Gnats have 4 life stages:
Fungus gnat eggs will hatch after about 3-6 days, hatching little larvae (translucent like maggots)
These larvae feed on the fine root hairs of the plant, the larvae will do significant damage if feeding on a seedling/cutting or an unestablished plant.
If you have a big healthy established plant the larvae can still cause problems, so rather than ignore we should treat immediately to preserve the immediate issue and allow the plant to reach is maximum potential.
Fungus gnats are rather easy to control if the infestation isn’t bad, but if your infestation is bad your fruits/flowers will act as sticky traps.
Until now, the most commonly used products to remove Fungus gnats have been vastly inadequate and thus, the fungus gnat still thrives in grow rooms everywhere.
Most commonly used products to remove Fungus Gnats
Diatomaceous Earth & Sand
Hydrogen Peroxide (H2O2)
A new product I recommend which is highly effective in the removal of Fungus Gnats is Triple R, by Lost Labs Nutrients. This product has been the best tool I have come across in removing infestations and preventing Gnats from returning. Triple R also aids in replenishing essential minerals back to the roots that may have been stripped by a Fungus Gnat infestation.
Get ahead of pests and don't let Fungus Gnats become an issue in your grow room.
Vapour Pressure Deficit (VPD) is a metric most growers either don't know or don't care to monitor, foolishly.
What is Vapour Pressure Deficit (VPD)?
Simply put, VPD is the measurement of pressure in the atmosphere, which is measured and altered by temperature and humidity.
Why does knowing my VPD matter?
Knowing your VPD will let you know how your plants are going to respond to the atmospheric pressure and allow you to prepare accordingly.
How does my VPD affect my plants?
The VPD in the grow room will determine how your plants transpire. This directly relates to your plants ability to consume nutrients and water.
If your VPD is too high or low, your plants will be over or under transpiring, leading to massive problems nutritional problems if you are not prepared or aware of how to deal with the situation.
What happens if my plants over or under transpire?
This is essentially the key to why VPD matters in the grow room.
If your plants are under transpiring due to your VPD being too low, this is a result of humidity being too high, relevant to the temperature in the room, causing high atmospheric pressure and preventing or reducing healthy transpiration of your plants. This will result in your plants under drinking or consuming through their roots, leaving excessive moisture and nutrients in the medium, leading to compounding problems with feeding if left in this state.
If your plants are over transpiring due to VPD being too high, your plants will be drinking significantly more water through their roots to prevent drying out, leaving behind nutrients and effectively drying their own medium out much quicker than usual. This has a synergistic effect that can cause toxicity in the medium by altering the concentration of water to mineral nutrients, changing the ratio from what you originally fed to your plant.
A plant that has been fed 1.0 EC at 6.0 pH can quickly turn into a dry pot with 2.5 EC at 5.0 pH when the plant has been over transpiring for a prolonged time, leading to serious nutritional problems when the plant drinks again.
How do I find out my VPD?
To simplify VPD, just use this chart!
VPD Chart Source: http://www.just4growers.com
What do I do if my VPD is too high or too low?
Take whatever measures you can to alter your grow space temperature and/or humidity to a safe VPD range for your plants current growth stage, as referenced on the above chart.
In part two of this tutorial Jase is giving out some crucial growing tips that a lot of growers overlook, by implementing them you will eventually form good habits in the grow room allowing you to grow the best possible crop, grow after grow!
TIP 1 – WATER CONTROL! CALIBRATE YOU EQUIPMENT (EC & PH)
Every day we are doing something in our growing space, that constant maintenance pays off in the form of healthy crops abundant in flowers. Sometimes, it doesn’t go to plan though and usually we can go back and determine that human error was the cause. The same thing goes for mixing up nutrient rich solutions, you may have memorised what the value of each dose represents in pH and EC, but do you check your run off?
Do you know what your pot/rootzone is ‘holding’? To put this simply, if the EC range of the pot is over 2.4-3.0 then no matter what you feed them they will only consume water because of the accumulation of food which only increases the EC and acidifies the water.
Always check your pH and EC measurements from your run off and you will have much better results.
TIP 2 – LIGHTING CONTROL! NO LIGHT METER MEANS YOU DON’T KNOW
Artificial lighting systems for indoor growing are intense. High-end LED lighting for example outputs serious amounts of light energy and very minimal thermal energy.
The light that leaves a fixture is measured in PPF(Photosynthetic Photon Flux), light hitting plant canopy is measured in PPFD (Photosynthetic Photon Flux Density) and over a specific photoperiod (duration) the PPFD measurement (per second) is multiplied to give us our DLI (Daily Light Integral) reading. If you’re already confused, then not having a light meter is going to be detrimental to your success.
Not knowing the amount of light your plants are receiving sort of negates growing in a precision based environment, imagine if you actually knew the exact number to expose your plants to in a specific phase, the purchase of one of these units will send your yields, floral form and quality through the roof.
TIP 3 – IPM (INTEGRATED PEST MANAGEMENT) PREVENTION IS MUCH CHEAPER!
We all know that growing indoors provides the perfect environment for plants, it also is the perfect environment for pests and pathogens to breed in. So many growers in mid flower come to us with pest problems, the conundrum here is that half of the consumable crop is now developing so spraying pest deterrents is not ideal as excess moisture in the flowering phase can aid in the development of botrytis and other fungal infections.
So what do we do? We go for prevention instead of painstakingly looking for a solution. The moment your precious seeds have germinated or cuttings have rooted, we highly encourage to spray once-twice weekly to prevent the possibility of an attack, by implementing this procedure the plants immune system will strengthen making it near impossible for a potential attack.
In this tutorial Jason gives you some crucial growing tips that a lot of growers overlook, by implementing them you will eventually form good habits in the grow room allowing you to grow the best possible crop, grow after grow!
TIP 1 – RUN-TO WASTE! (RTW) FOR COCO & ROCKWOOL GROWERS
If we feed the maximum dosage of food each day, this is called run to waste. Now the one thing some of growers can potentially overlook is the amount of food the pot may be holding.
Following a nutrient regime seems simple, you just add the recommended dosage to water confirming with your pH and EC pen the solution is within range and feed, for the most part plants thrive from this kind of input, but eventually at some point in the grow (usually flower) a deficiency or slowed growth (or no growth) can occur, they key is in the pot.
For example, if we feed our plants 1.6 EC each day consistently throughout the entire grow, there is only so much of that food that is being consumed on a daily basis, so, your input dose may be 1.6 but the plants may only consume 0.5-1.0 EC, the rest doesn’t just dissipate it is withheld, and bound between roots.
Because of this there is an accumulative effect of elements eventually causing the pH in the rootzone to become extremely acidic locking out access to the other elements. The fix, is to flush more frequently and actually collect a sample of the run off solution to test. If the EC is high you will need to first remove the excess buildup (Kleanse works great and works much quicker than just plain water) then resume feeding at 50% strength.
Always keep the pot EC under 1.8 and you will a very happy grower.
TIP 2 – RECIRCULATING! FOR HYDRO GROWERS
Unlike above, this method relies on a nutrient rich reservoir solution. The plants grow directly in this solution and the most commonly used substrates for this method are rockwool, LECA and perlite. The trick here is to not push the solution too hard, daily pH & EC checks are required.
The ideal scenario for hydroponic growing is an EC around 1.2-1.7 depending on the requirements of the plants, and instead of the system changing pH and EC daily, their value will ideally remain the same and the solution will be consumed evenly, slight tweaks of 0.1 EC per week seem to be the best way to manage this.
If you make a solution with an EC of 1.6 and the next day you check and the reading is EC 1.2 your plants have consumed 0.4 of that nutrient solution, this generally for hydroponic growing means, the nutrient strength is too high, so by lowering the solution by 0.2 may be all that is needed for the solution to be consumed evenly, meaning the EC, the pH and the water are all equally consumed, this is how you know your hydro system is on point.
TIP 3 – PRUNING & TRAINING! FOR ALL GROWERS
Plant training! In veg your plants can become monsters, try not to let the monster emerge when growing indoors, it’ll only mean light starved flowers and hours of trimming. Ideally, you would train throughout the vegetation phase as this will “set-up” our flowering phase.
If using HID systems (HPS & MH) you will need to remove all growth under the main canopy that receives the most light. Leaving this growth to develop will result in undesirable outcomes, usually fluffy and undeveloped due to lack of light. If you get down under the canopy you can see the shade, anything that exists in this space should be removed, i.e. thin stems, weak growth patterns and lacklustre in vigor.
Note: For HID systems I advise on training no more than 4-6 branches on each plant, for LED you can go up to 8 (4-8 main branches per plant) by doing this technique, plant uniformity and flower consistency are improved with less of the smaller flowers and excess vegetation)
For quality LED and CMH systems, both of these lighting applications are full spectrum, meaning they have every visible colour in the wavelength, training under these lights is still just as important but because of the presence of green and yellow light, the lower flowers are actually penetrated with an insane amount of light thus developing the flowers nicely, I would still remove any growth that looks weak or potentially sucking energy from a flower that could become much larger. The most important message here is to look after you plants in veg, set them up right, and they will reward you in flower.
TIP 4 – WRITE IT DOWN, DATA IS RECORDED, NOT MEMORISED
Whenever we do something in the grow room, this information should be recorded simply to allow a grower to retrace their steps and re-correct. Without that information you’re just guessing or loosely remembering ‘what you did’ so, if the mindset is the same grow after grow, the results will reflect.
Changing things does not mean you have to relearn how to grow, it could be a simple as recording pH and EC to start with and then build from that and expand the detail involved, eventually you will call on the information and it can save you big time!