In a fascinating and fun turn of events, more outdoor cannabis cultivators are using supplemental lighting to alter the photoperiod their crops are receiving, with many saying it’s essential. In particular, it’s outdoor cultivators below the 30th parallel who are finding the photoperiod of the variety of cannabis crops cultivated in northern regions aren’t matching up with theirs’. This includes Hawaii, Louisianan, Florida, and parts of South Texas.
As a short-day crop — extremely rare with the fruits and veggies we eat — cannabis won’t flower if it’s getting more than 12-14 hours of light. When it’s not flowering, cannabis is in its vegetation phase, where it will continue to grow bigger until the light it’s receiving drops below its critical photoperiod.
During the summer in the United States, it’s not uncommon for places in the South to see shorter day lengths than in the North by up to two hours. This can give a place like Baton Rouge, LA, only two to possibly just one week to run their crops’ vegetation cycle, depending on germination/propagation time.
If you’re experienced with cannabis cultivation, you may be familiar with the significance just one extra week in the veg cycle can give you. It can allow a plant to essentially double its size and potential yield. With cultivation costs essentially the same despite regional discrepancies, this can give a state like Michigan — which can potentially give a farmer seven weeks to run their veg cycle — an unapparelled advantage.
But it isn’t all rosy for the Northern States as it’s just not the Southern States who are finding supplemental lighting essential. Moving to the uppermost northern regions where cannabis is grown outdoors, you’ll find cultivators struggling with both late spring and early fall frosts. The last spring frost in many Northern states can vary by more than a month. This means a late frost can cut the final yield by more than half. And, an early fall frost can be quite damaging to plant tissue.
The Old Fix
Whether it’s a late frost or short summer days that cause outdoor cannabis cultivators to lose out on the critical veg cycle, a popular solution is to simply plant varieties of cannabis that tolerate shorter light periods without immediately flowering.
But not only does this make planning more difficult, particularly for the Northern States, but it also prevents places in the South from growing many of the most popular cannabis strains.
A Better Solution To Troublesome Short Day length
Fortunately, thanks to LED technology’s revolutionary advancements in efficacy and efficiency, outdoor cultivators now have a better solution. One that eliminates the headache and disadvantages of choosing which variety to grow.
It’s no secret that indoor gardeners have many advantages over outdoor counterparts, with their ability to manipulate their growing environment. However, commercially and for the at-home grower, these advantages are soon squashed when indoor growing costs are taken into account. One, if not the biggest, cost factor in indoor cultivation is power consumption driven by running artificial lights. During the vegetative period, a cannabis crop indoors is typically given 18 hours of light per day — some will even keep lights on 24/7 or close to.
In the past, supplementing in traditional grow lights like HIDs, just wasn’t feasible. Sure, it could help extend the day length for increasing yields, but the cost of setting them up, running them, eliminating excess heat, etc. all cut into any of the extra profit. However, today’s LEDs can produce the same amount of light as HIDs can and at nearly half the cost.
As well, unlike traditional grow lights, which are mostly a big unit consisting of a single bulb and reflector, LED grow lights come in a wide variety of designs, from bars to strings. This is big because not only does this improve issues with heating, relocating plants, etc., it makes it more affordable and easier to surround the plant in light. This is a must because if a portion of the plant doesn’t get direct light, it will flower, and this can open a bigger can of worms.
This makes supplemental light with LEDs a great idea for both outdoor commercial operations and for those that grow at home.
Even When Day length Doesn’t Need Extending, Supplemental Light Outside Offer Advantages
Not only has the superior efficacy of LEDs greatly helped indoor growers cut down on their electricity bills, but it also gives them the ability to utilize photomorphogenic steering techniques. Grouped based on their wavelengths, the photons that our plants use for growth can also change how they grow, depending on which part of the light spectrum they’re coming from.
For example, light particles from the UV and blue portion of the light spectrum tell plants to focus their energy on producing secondary metabolites like vitamins and antioxidants over growing bigger. This may allow a grower to increase their cannabinoid or terpene content by running brief periods of heavy blue light late in flowering. Outdoors, during late flowering, cannabis plants naturally are only getting very minimal amounts of blue light.
With LEDs, growers can use different colored lights to grow their crops in the way they want. If an individual plant is short, they can use extra far-red light to trigger them into quickly stretching (shade avoidance) to catch up with the rest. Likewise, if a plant is stretching too much, the grower can reduce its far-red light, or increase its blue light as it also impedes cell expansion.
Again, this makes supplemental lighting with LEDs advantageous for both commercial grows and the home gardener the prefers growing outside.
As is often the case, modifying our crops with an array of techniques that aren’t necessarily found in “nature”, has been essential to modern agriculture.