Sunlight, in all its forms, has shaped and driven the living of many organisms for billions of years. Yet, as sunlight isn’t available all year round due to seasonal changes or geographical restrictions, artificial lighting steps in to do the job.
The full spectrum LED grow lights for indoor plants, in particular, does a great job of mimicking the sunlight, even including the primary compound of solar radiation, the UV rays.
For as long as we can remember, UV has been a synonym of toxicity and harmful properties; however: anybody who ever tried giving their plants a little bit more sunlight knows this is how you grow plants faster. If the exposure is of the correct duration, intensity, and placement, plants can complete their growth cycle very fruitfully.
This requires a comprehensive understanding of “How Long To Leave UV light On Plants.” Well, this guide revolves around the same topic in detail. So, Keep reading!
Understanding UV Light and Its Role in Horticulture
It’s pretty well-established that UV light is the most harmful substance of solar power radiation for humans, and we’ve well understood why. But, when it comes to plants, you’ll surprised by how it’s unlikely to cause severe damage to most crops. UV rays have in fact continued to be pertinent for indoor farming and horticulture setups, especially when it comes to contributing plant nutrient uptake, growth factor, and ultimately overall yield.
Yes, UV light especially its UV-A and UV-B elements has this biologically active nature that helps plants regulate most of their growth journey.
UV-A is the milder one, closest to visible light, and it makes up about 95% of the UV radiation that reaches us. For plants, UV-A is pretty beneficial, helping them develop thicker leaves, deeper colors, and just overall become more resilient.
UV-B, on the other hand, is a bit more intense. Too much UV-B can damage plants, but in the right amount, it’s super helpful. It boosts the production of certain compounds that act like natural sunscreen for the plant, making them tougher and more resistant to things like pests and stress. It can even improve the taste and nutrients in the fruits and veggies you’re growing!
How Plants Respond to UV Light: Benefits and Potential Risks.
Plants have this unique relationship with UV rays and by harnessing its power in just the right way, plants are able to complete their growth cycle in a much more efficient and fruitful manner.
A horticulture expert suggests that if you want your crop to be tasteful, fresh, and rich in flavor, expose your plants to UV lights. The vibrant color, aroma, and taste are due to the plant resin production under UV Light.
Studies reveal that UV wavelength can change compounds that control taste in crops such as strawberries, tomatoes, and blueberries.
Other research shows that ultraviolet light makes strawberries and red lettuce a deeper red with more antioxidants.
Ultraviolet light has contributed to speeding up photosynthesis and increased plant growth, which means an increase in the root mass of your plants and veg branching with less stretching, resulting in tighter internodes and heavier harvest weight.
A study published in Oecologia concluded that exposure to UV-A light increased photosynthesis by 12%. Another study published in Scientia Horticulturae found that UV-A light has healthy effects on crops, including inhibition of extension growth, increased leaf thickness and thicker cuticles, and greater leaf coloration, making plants potentially more resistant to environmental stresses and pests.
However, UV radiation, as a valuable contributor to plant growth, is not just beneficial in all senses, but it can also exert warming and destructive effects. The harmful element is directly linked with how well you deliver the UV to plants, including the radiation source and its intensity and duration.
Obviously, An excessive dose will typically burn leaves and, thus, ruin your crop from every angle. The downside is only because of using UVs incorrectly in the grow room
Sensibly, If humans are asked to be protected from UV rays, it’s the same for plants. However, you can invest in a greenhouse grow light for your plants, referring to the Nanolux full spectrum LED grow lights that emit the preferable spectrum of light for the plants to grow properly.
Examples Of Plants Benefiting From UV Exposure.
Certain plants, including cannabis and hemp plants, lead to higher flower quality, potency, and weight when put under UV lights, and that is due to the increased production of compounds such as THC. Reports reveal that UV rays help improve the THC content by an incredible 28%.
This is because UVA light increases secondary metabolite activity in Cannabis, Such as cannabinoids THC and CBD, as well as terpenes, which give cannabis its distinctive aroma.
Many growers have also witnessed that by keeping the right balance of UVA and UVB light, their plants enhance the flavor and quality of certain crops, such as tomatoes and berries.
Additionally, desert plants that grow naturally in areas with high UV exposure are better able to thrive under UV light than plants that grow in shaded or low-light environments.
The list also includes plants thriving at high altitudes. Because they’ve unobstructed access to abundant clear sunlight, their spectrum is higher in UV wavelengths than at lower altitudes.
Determining the Optimal UV Light Exposure
Our perception of light, which tends to be very colorful, seems quite different from the plant perspective. UV undoubtedly does a lot of wonderful things for plants, but their dark side becomes evident if applied incorrectly.
The best practice is to identify the desired amount of UV rays on plants, considering all the following factors.
Factors Influencing UV Light Requirements: Plant Species, Growth Stage, And Environmental Conditions.
Plant Species
UV light appears to have a positive effect on the growth of plants, but not all plants respond equally. Many statistics prove that some plants under UV produce higher yields and profits, while others are impacted negatively, as evidenced by many experiments.
For instance, rice plants treated with UV-C were found to be less palatable and more susceptible to pests, thus, it leads to lower consumer interest and purchase intention. However, sweet cherry fruits under UV-C radiation have shown a decreased respiration rate, but the content of aspartate remarkably increased.
Contrary, UV-C on fresh-cut strawberries increased phenolic compounds and activated the phenylpropanoid pathway to enhance antioxidant activities without reducing fruit quality.
Growth Stage
Based on a professional suggestion, it is ideal to include UV light in plants when they are in the middle to the last few weeks before their flowering.
During their flowering period, add 60-90 more minutes of UV light during early flowering and extend that to a 90-120 minute photoperiod halfway through the flowering stage.
At the end of their flowering phase during the last 2-3 weeks, it is also good to boost with the extra UV light for up to 120 minutes. This can therefore result in your plants having higher or lesser THC and other chemical stuff.
Bear in mind, that UV light is treated differently by different types of plants, so it is important to monitor your plants as you increase the time.
Environmental Conditions
Climatic differences in region and differences in the availability of natural resources make the assessment of the proper UV light difficult. The same UV-watt bulb will have its effects on crop productivity in different regions of the world, so being able to take even more measures of the environmental conditions into account here would be important.
During dry and humid weather conditions, a greater amount of UV exposure is advisable. Similarly, plants that have a natural habitat of growing at higher latitudes require an extensive degree of UV than those thriving at lower.
General Guidelines For UV Light Exposure For Common Plant Types.
UV light might sound like something that could burn your plants, but it actually has a pretty important role in indoor gardening. As a matter of fact, if you’re growing with commercial LED grow lights, you should definitely be supplementing your plants with some form of it.
The UV light requirement for all plant species is generally very low. Even though some folks think UV isn’t necessary during the vegetative stage, it really does help. By offering UV light to your plants during propagation & early veg, they tend to develop thicker cuticles, faster metabolism, and just be overall stronger and healthier.
This means they’re more likely to give you a bigger and better harvest down the line. Instead of blasting them with a ton of UV light at specific times, it’s smarter to use a small amount of UV light throughout their entire growth cycle. It’s safer and more effective.
Here, Opting for the best LED grow light for indoor plants would ensure your plants get the right amount of light exposure to thrive and produce outstanding results.
Implementing UV Lighting in Commercial Grow Operations
If you’re into the commercial horticultural business and wish for your plants to have greater growth and productivity, believe me, UV lighting can be a serious game-changer for you.
Here’s a casual rundown on how to make UV lighting work for your grow operation and some real-world examples of successful setups.
Best Practices for Using UV Lighting
- Start Slowly: Don’t go full throttle with UV light right away. Plants need time to get used to it, so start with shorter exposure times and gradually increase as they adjust. This helps avoid any potential damage, especially for young or sensitive plants.
- Place Lights Wisely: Positioning is key. Keep your UV lights about 18 to 24 inches above the plants. This distance helps ensure they get enough UV light without risking leaf burn.
- UV-B Timing: Many growers use UV-B light during specific growth stages, like flowering, to boost plant quality and resilience. For best results, try using UV-B in the later stages of growth to enhance flavor and stress resistance.
- Schedule Smartly: UV light should be a supplement, not a replacement, for your regular grow lights. A typical schedule is to run UV lights for about 2-4 hours a day, either at the beginning or end of the light cycle.
Scheduling UV Light Exposure: Daily And Seasonal Considerations.
Scheduling Light quantity (intensity and photoperiod) and quality (spectral composition) have a great impact on plant growth and physiology. These lights, more than providing the energy for photosynthesis, also dictate specific signals that regulate plant development, shaping, and metabolism.
Remember that plants are different, and the amount of UV they can bear varies, too, even between plants of the same strain.
So it’s suggested to give your plants just 2 hours of exposure per day, split into 2x 1-hour stints initially.
You can even increase these 1-hour periods by 15 mins every 2 days. If you notice a little burn on the smaller top leaves, reduce the exposure time by 30 minutes per stint.
Follow this procedure to calculate that sweet spot between giving as much UVB as possible but without causing detrimental damage to their plants.
Real-World Success Stories
Some commercial growers have nailed the use of UV lighting. For instance, many agricultural farmers reported that by taking the help of UV-A and UV-B lights, they were able to promote plant growth and productivity. Through precise control of light placement and duration, their plants were able to fend off pests better as well as they experienced less stress.
Similarly, some commercial retailers that deal in indoor leafy greens added that in the last couple of weeks, they also used UV-B lighting in their final growth weeks to increase the nutritional value of their spinach and kale. This late-stage UV exposure has helped them produce high-quality, nutrient-packed greens.
By utilizing the tips in this guide and the experience of successful applications, UV lighting can be an impactful addition to your commercial grow operation, increasing plant health and harvest yields.
Monitoring and Adjusting UV Light Exposure
So, Are you convinced enough to use UV lighting for your indoor gardening setups–Awesome. But how will you figure out you’re doing the right thing at the right stage? That’s when you’re going to monitor each and everything.
Here’s a casual guide to help you out with this journey.
Keeping an Eye on Your Plants
- Screening: Check your plants out with regular visual inspections for pests or signs of stress. If you observe any problems like leaf burn, discoloration, or slow growth it is likely that your plants are getting too much UV exposure. Healthy plant leaves look green and perky.
- Photo Records: Take pictures of the plants and record plant health over time. Reviewing photos can help you identify any trends or shortcomings associated with UV light exposure, and help you to determine where things need to be adjusted.
- UV / Environmental Sensors: Deploy UV intensity and environmental conditions monitors. Accessories like this can report UV levels but also other pertinent variables like temperature or humidity that could simultaneously affect plants’ responses.
- Leaf Checks: Every now and then, test your plant leaves for stress or nutrient issues. This can give you a clue about how your UV light setup is affecting them.
Adjusting UV light Exposure Based On Plant
If you want to protect your plants from harmful UV-B rays, it makes more sense to alter the concentration levels of these lights. Remember that plants have negligible UV light requirements, so literally, before you go all out and spend money on a commercial UV growth lamp for your plants, keep in mind that less is fine.
To get the results you desire, 2-3 watts of Ultra Violet light per square foot of your target growing area is sufficient. For instance, using a 4′ x 4′ tent, you should provide about 32-48 watts of UV lighting when growing.
The perfect solution is to run UV light together with an LED grow light. This would enable the grower to fine-tune the light spectrums according to specific plant demands.
A commercial LED grow light with UV would be a great addition to your other lights. This would not only allow you to control the spectral output but also save on energy consumption as well as replacements.
A full spectrum LED grow lights mixed with some supplemental UV bars can also do wonders in terms of growth.
Troubleshooting Common Issues With UV Light Exposure In Plants.
As I mentioned earlier, each plant species has its own optimal circumstances for growing. When you give some plants too much UV, they get stress signals like discoloration and wilting in their leaves. Such a concern can be addressed by adjusting the distance as well as intensity between plant and light.
Typically, however, a plant growing room using UV lights will become very hot. That is a consequence of the characteristic of the UV spectrum for being a high-intensity power. Here, all you need to do is to take hold of an efficient greenhouse grow light to improve the inside temperature, so that plants can well-flourish with optimal spectral levels.
Signs Of Underexposure And Overexposure To UV Light In Plants.
One sign that your plant is not getting enough UV is evident from its fewer color pigments, delayed flowering, and lack of taste. This happens because plants put most of their energy into growing vertically in search of more light. So, their natural nutrient level fails to develop.
The result is a negative effect on the production and content of secondary compounds, such as anthocyanins and total phenolics.
Overexposure to UV-B radiation has been shown to result in plant bleaching or faded leaves. You may experience cell death in plants, which induces oxidative bursts and subsequently disrupts the function of the vital organelles, chloroplast, and mitochondria.
Conclusion
Getting the most out of your plants involves more than just providing the basics. Effective manipulation of UV light is the key to optimizing growth and yield and make your crops healthier as well as profitable. Learning the UV light requirements that your plants have and correcting exposure can help you to produce better yield, quality deals with your results.
When you are looking to bring your grow game to the next stage, Nanolux has you covered! Their full spectrum LED grow lights are designed for different kinds of plants and grow setups, so you can get one that suits your unique needs best. Their specialists are available to offer tailored guidance and help you optimize your lighting for the best possible outcome.
Reach out now and see how their tailored solutions can make a difference for your plants!