Best lighting for growing cannabis
Lighting types, schedules, and electrical money-saving tricks—you will be amazed at how much you can use lighting to your advantage in the cannabis grow-op.
As you progress in your journey toward becoming a grandmaster grower, you will soon start identifying the limiting factors in achieving those glorious yields we all love to see in photos and videos.
Inarguably, lighting is one of the biggest and most immediately recognisable of such limiting factors. Within reason, the more light you give your plants, the more they will yield.
Other valuable aspects of growing include environmental conditions like CO₂ levels, maximum and minimum day/night temperature, and relative humidity range. Nutrition is also of equal importance. Feeding needs to be adjusted to what the plant is asking for based on its phase in the grow cycle. Some growers even go the extra mile and have classical music or biowaves playing to stimulate the stomata to squeeze in a little extra growth spurt. However, the jury’s out on whether this yields any noticeable results—but it can’t hurt!
Light is, in itself, just another type of “food” for plants. Keeping this in mind will allow you to better decide what is right for you. Just like an athlete has a specific dietary regime for his sport, so must you consider what is the ideal type of light for your growing conditions.
There is little point in blasting your cannabis plants with 2000W/m² if you are just getting started, or deciding on the latest and greatest LED fixture if you cannot dial in the right ambient temperatures. Plant height and spatial limitations also play very important roles depending on which type of lights you decide on.
In this article, we will give you rundown on what constitutes the “best” light for growing cannabis. There are many pros and cons to each, and a little information goes a long way.
A BRIEF HISTORY OF THE GROW LIGHT
In the beginning, there was light…from the sun! Then cannabis became illegal, and someone had the brilliant idea to bring a powerful street lamp indoors to simulate the sun and grow weed.
Not only did this work, but it also created a massive industry catering to indoor/greenhouse operations. This lighting technology is called high-intensity discharge, or HID. Typically, these lights come in one of two varieties, either sodium or metal halide. These lights are very strong, quite inefficient, and produce a substantial amount of heat. But if you manage to tame the heat, they get the job done fantastically well.
Primarily due to space constraints, some growers started experimenting with lower-powered and more efficient lights. More efficient means less electricity is lost to heat, and more of it transformed into actual light. For instance, CFLs—compact fluorescent lights—are quite efficient, small and compact, cheap, and readily found in any common hardware store or supermarket. Ideal for seedlings and clones, they underperform for flowering. This is due to the limited light spectrum they produce. On the other hand, you will be able to fit a few of them inside a covert, desktop PC micro-grow retrofit.
In recent years, we have witnessed the beginning of a new artificial agro-specific lighting era. Modern LED fixtures are superbly efficient, while at the same time producing a great PAR, which means photosynthetic active radiation. This is the measure of the quality and intensity of the light spectrum that the plants actually use for photosynthesis. This in and of itself does not necessarily mean LED is better than HID or CFL—it just means it fills a huge gap really well.
A special mention to plasma fixtures. While operating under the same principles of HIDs, they do have a better spectrum than sodium or metal halide bulbs.
LIGHTS ON, LIGHT OFF
Light schedule is something quite often overlooked. Some growers take years to realise they can further manipulate their plant’s behavior in their favour, with simple light schedule tricks.
The typical schedule will be something like 18 hours on and 6 hours off during the vegetative period, and a flat 12–12 for flowering.
But did you know you can do so much more? You can save significant amounts of electricity if you employ the gas lantern routine during the vegetative period, while maintaining a high level of performance.
Giving your cannabis plants 24 hours of darkness before switching to flowering is known to induce sexing substantially faster in many strains.
During flowering, if you progressively decrease the lights-on period, you will trigger the plant to speed up production. This can be done by setting your timer to turn off 10 minutes earlier each week until harvest. This will simulate the natural shortening of days as autumn sets in while saving you a little extra on electricity.
This technique is sometimes referred to as light deprivation or the diminishing light technique.
Some growers swear by a 10–10 flowering schedule. The theory is that you will trick the cannabis plant into shorter day cycles. You can fit 8.4 “short days” in each week. That means that a typical 9-week strain (63 days) can be ready in 7.5 weeks (52.3 days).
Even autoflowers can benefit from experimentation, so do not be shy to try it out for yourself.
SAVINGS, SAVINGS, AND EVEN MORE SAVINGS
Even if electricity were free, getting into a habit of saving electricity will not only be an environmentally conscientious thing to do, it will further improve your skills. Understanding and measuring your environment will save you time and money while improving the potential of your plants.
Investing in an automated exhaust system works wonders to save on heating. In the winter, exhaust fans will blow slower, thus conserving heat. Mid-summer, they can work full-power to keep things under control. Many modern inline–exhaust fans come already pre-built with heat sensors for this very purpose.
This can be done cheaper by manually using a quality variac transformer. These will slow your fans down while prolonging their life. Do not confuse variacs with typical dimmers, as these will create a noticeable hum and take a heavy toll on your gear.
If you use butane/propane heaters to warm up your house, slowing down the fans will not only help conserve heat, but will have a dramatic effect on the available CO₂, which will boost production potential considerably. Higher CO₂ levels also mean you can run the grow room at higher temperatures, so it is a win-win situation.
If using LEDs, you can lower the lights closer to the canopy without burning the leaves or buds. You’ll notice you will be using fewer nutrients and water while your girls flourish considerably better.
There are dozens of little tricks to boost yields and save on productions costs. From training, stressing, environmental manipulation, and of course, lighting. But there are no silver bullets.
There is a reason experienced growers swear by one method over another, or one type of light over the next. Even the biggest commercial operations have radically different approaches.
Different genetics, different growing mediums, different growers—this is a never-ending debate. And thankfully so, as it keeps us on our toes and on top of our game in pursuit of top-quality buds.
Remember that what works for one person may be a complete flop for the next. Experiment slowly and gradually introduce the next features—never make rash decisions. This way, you will be able to judge what works and what doesn’t for your operation. Also, be sure to take notes and pictures so you can track your progress.
As you improve and create a deep relationship with your secret garden, you will certainly reap the rewards of the efforts you put into it.
Traditionally, most cannabis requires long days of full sun to produce its full potential of luscious bud harvest.
Offer enough Light for Cannabis Seeds
Apr 16, 2019 · 6 min read
Cannabis seeds don’t need light when they are germinating. In fact, they require an absence of light. All of the methods below call for darkness.
Once they have sprouted, they will need a lot of light — 18 hours a day, to be exact (though you could even give them 24 hours of light per day).
How To Germinate Cannabis Seeds
There are several methods for germinati n g marijuana seeds, each with their pros and cons. We will cover the best methods below, with the first method offering the best chance of success and the last one offering the lowest chance.
These seeds are expensive, so we recommend using the method with the best chance of success, so you reduce the risk of wasting seeds as much as you possibly can.
Germinating Cannabis Seeds In A Propagator With Peat Pellets
You get the highest success rate when you provide the perfect environment for germination. A propagator ensures optimal control over the environment.
Whether using peat pellets or rapid rooters, this method ensures a high rate of success, but it does require the purchase of a propagator and the pellets or rapid rooters.
You can save a bit of money by skipping the propagator and just rigging something up yourself (or not using any type of covering at all), which is what we’ll cover next.
Using Peat Pellets With No Propagator (Or With A DIY Propagator)
If you are on a bit of a budget, you can forgo the propagator and just use peat pellets on their own. You could even make a DIY propagator by simply using some kind of plastic cover.
lower cost than using propagator
peat pellets (or rapid rooters) still offer the best chance of success, even without a propagator
less control than with propagator
if using a DIY propagator, requires time to construct
A great DIY solution is to use simple plastic cups, one for each peat pellet. Cut the top off a small plastic drink bottle and place it over the peat pellet with the seed as a dome.
But you don’t need any propagator at all.
Covering the seeds helps keep in the moisture and makes it easier to keep them warm, but it is not necessary. You can just as easily keep the peat pellets uncovered, as long as you ensure they stay moist and are kept in the correct temperature range.
Germinating Cannabis Seeds Using Paper Towels
This is probably the most written about method, but that does not make it the best. It is easy and you won’t need any additional equipment, but it requires handling the delicate seedling.
no additional equipment required (assuming you have paper towels)
requires transplanting the seeds, which risks damage
need to ensure the paper towel stays damp, but not wet
The only thing you need for this method is a paper towel, although I would also recommend using two plates.
For the paper towel, you actually want to use the cheapest brands. More expensive towels are more porous, which makes it easier for the delicate root to get stuck and tear off when transplanting the seedling.
For this method, place a paper towel on a plate and get it nice and wet. Drain off any excess water, though. It should be damp, but there should be no standing water or the seeds can drown.
Put your seeds on one half of the paper towel and fold the other half over them, so that they are covered. Then take the second plate and put it upside down on the bottom one, forming a dark cavern between the two plates for the seed to germinate.
Check once or twice a day to ensure that the paper towel never dries out. If you need to add water, make sure that you always drain out any standing water. Keep the seeds covered and at the correct temperature. They should sprout in a few days.
Once they have sprouted, you’ll want to transfer them to soil or a growing medium. See below for instructions on how to do this.
Germinating Weed Seeds In Soil
This method is the easiest, since you simply let the seeds germinate in the same place where they will grow afterward. Not having to transplant the seed after it sprouts means you don’t risk damaging it causing it shock that will slow growth. The main drawback is a lower success rate.
no transplanting required
no additional equipment required
lower success rate than other methods
All you do for this method is poke a hole in the soil or growing medium that is about half an inch deep (1.5 cm). Place the seed in the hole and cover it up. Ensure that the soil or growing medium is moist, but not soaking wet. The temperature needs to be in the correct range as well.
You should see the tap root poking out of the seeds by then. If not, you’ll want to continue germinating the seeds elsewhere, perhaps in soil. If they are submerged in water for more than 24 hours, there is a risk that the seeds can drown.
My Seeds Germinated, Now What?
Once the seeds have germinated, it is time to transplant them into soil or a growing medium. Be very careful not to damage the delicate taproot. Ideally, use tweezers to handle the seeds, to avoid any oils from your fingers doing any damage.
Plant the seeds about 1 to 2 cm deep, so that it does not require too much energy for the stem and first leaves to pop up through the soil.
Make sure the soil is moist and the seeds are kept at the correct temperature of 68° to 82° F (20° to 28° C). Your little plants should pop out of the soil within a few days.
At this point, the seeds will want light, and lots of it. Even if they are still beneath the soil, you can go ahead and turn on your grow light.
If you do not have a grow light, there are a number of different types you can consider. For seedlings, fluorescent lights or LED light bars (like the veg/clone bars from Secret Jardin) are ideal, unless you are germinating a lot of seeds at once. Then you might want to consider a larger Plant LED grow light.
Best LED Grow Lights For Starting Seeds
The best LED grow light for seedlings is the AIS led GROW LIGHT. It was specially designed for seedlings. The main drawback is that it is made to cover a 2 by 4 foot area. If you only have a few seedlings, this light will be overkill.
LED bars are the best LED lights for seed starting when you don’t have enough seedlings to fill a 2 by 4 foot area. These bars from Secret Jardin are a great choice. They are inexpensive and give off enough light to get your plants through the seedling stage in no time.
HPS Or MH For Seedlings
You can put seedlings under HPS or MH light, but I would only suggest this if you already have the lights. It is more cost effective to use LED or fluorescent lights.
The only time MH or HPS really makes sense is if you keep your plants in the same space from seed to harvest, i.e. you do not have a separate area for seedlings.
Metal halide light is better for seedlings than HPS light, since they need cooler light with more blue light than red.
When To Put Seedlings Under MH or HPS
You can turn the grow light on once the seeds have sprouted and they are in the soil or growing medium. Even if the plant is still not visible, the heat from the grow light will actually help warm the soil, which encourages the plant to grow.
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Cannabis seeds don’t need light when they are germinating. In fact, they require an absence of light. All of the methods below call for darkness. Once they have sprouted, they will need a lot of…