During the summer months, heat-stress, pests and diseases become a major concern for your indoor garden. Many growers choose to shut up shop for a few months, leaving a gap in the market for your fresh produce if you can keep things going. We'll talk you through the equipment you need to keep everything running sweetly, along with a few tips for getting the most out it.
Choosing the right grow light(s) is one of the single most important things to get right. Old-school HPS grow lights made it incredibly difficult to grow during the hotter months, thanks to their higher operating temperatures. Luckily, LED grow lights are affordable and deliver jaw-dropping efficiency levels, running at much lower temperatures and making your environment a hell of a lot easier to manage.
Most LED grow lights are dimmable straight out of the box, giving you a greater level of control. If conditions get too hot, and you've tried every other measure, you can turn the output level down. Running at a lower output setting is better than stressing out your plants or shutting up shop altogether. Less heat = less heat stress; it's that simple!
One quick tip - when programming lighting patterns, set your lights to come on during the night. This alone will make the battle much easier, by taking advantage of the coolest part of the day.
Improve your extraction & ventilation systems
Extracting plenty of air from the grow space will naturally draw in cooler air from outside. Over-speccing your duct fan will allow you to remove as much air as possible. Pair up this up with a fan speed controller that's thermostatically controlled and your fans will work harder when needed, maintaining constant temperatures.
To keep your extraction system working as efficient as possible, keep the ducting runs nice and straight. Curves in the ducting (especially tight bends) cause air to hit the sidewalls, generating extra friction. This reduces airflow while increasing noise levels: not good! A simpler and straighter extraction set-up will get the best possible performance from your duct fan.
Increase air circulation fans
Microclimates can create hot spots in your grow room, causing certain areas to experience high temperatures. Circulation fans allow you to distribute air nice and evenly, making the environmental conditions in and around the grow space as equal as possible. By creating gentle air movements, proper air circulation strengthens the stems of your plants, toughening them up and making them more resistant to pests and diseases.
Pointing oscillating fans towards appliances that get hot, such as lights, ballasts and even chillers, helps to distribute the excess heat. However, keeping these items outside the grow space altogether is the best solution.
Increasing CO2 levels
CO2 is found naturally in the air at around 400 parts per million and is needed by plants for the process of photosynthesis. Increasing CO2 levels to around 1000 PPM can have truly profound effects on growth rates. Many growers see yield increases of 20% or more when it's done properly! The robust growth rates that CO2 supplementation delivers allow plants to cope with temperatures higher than usual, thriving in temperatures of 29 degrees or more, making CO2 a godsend in the summer.
For beginners, go for the Mother Nature CO2 Generator before moving up to something like an Autopilot.
Cooling and sterilising your nutrient solution
For as effective as the abovementioned environmental control is, it's not the only area you'll need to pay close attention to. The temps of your nutrient solution are just as important as those of the air, if not more so. Keeping nutrient temps in the sweet spot of around 18-21 degrees will maximise oxygen levels, helping to ensure that solutions stay free from pathogenic bacteria and fungi.
Using a chiller is by far the easiest way to manage the issue during the summer. A chiller works in a similar way to a refrigerator, maintaining the nutrients that are pumped through it at set temperatures. This acts like a cold beer would for a human, refreshing plants and keeping them nice and cool.
You may also notice that your pH & EC fluctuates more in the summer. More water is lost through transpiration / evaporation when conditions are hot and dry, causing dissolved salts to become more concentrated. The effects of overfeeding are much more damaging than underfeeding, making it a harder issue to correct once the damage is done. Stay on top of the issue by keeping a close eye on EC levels, adding in extra water when levels creep above those specified by the nutrient manufacturer.
Another product that you should sneak into your summer regime is Silver Bullet. Silver Bullet keeps your tank sterile, massively reducing the likelihood of encountering root diseases like pythium (root rot). Once your plants are infected, it's very hard to save them: if you're lucky, you can battle through it and make it to harvest, albeit with a reduced crop-size. It makes MUCH more sense to prevent the issue from occurring in the first place. Silver Bullet kills 99.9% of pathogens and lasts in your tank up to five weeks, giving you comprehensive protection. It's also great for general system cleanliness, as it breaks down biofilms, preventing blockages and keeping your system running sweetly.
Icetube pipe is another must-have for grow system. The white reflective lining of the pipe can reduce nutrient solution temperatures by 4-6 degrees, minimising the chances of encountering root rot.
Other useful additives
Silicon is a great additive generally, but it's essential in the summer months. Silicon works by strengthening individual cell walls, which improves the structural integrity of the whole plant. Expect to see thicker stems and stronger branches that can support lots of weight. The general increase in robustness allows plants to cope with the stresses and strains of the summer much more easily. There are quite a few silicon products to choose from, but our favourites are Plagron Silic Rock & Shogun Silicon.
Speaking of Shogun, all their base nutrients come with technology known as SmartZen which allows them to cope with heat stress in high temperature situations, adding another level of protection through the hot summer months.
Pests & disease prevention
During the summer, pests multiply rapidly, and if left untreated, can wreak havoc in your grow room. Prevention is always better than cure - don't wait until your plants are riddled with bugs before taking action! Use Canna Cure once a week and it will strengthen up leaves by creating a breathable 'second skin'. At the same time, it will ward off an array of troublesome pests.
If you've already let things get out of control and you're looking for a quick fix, check out Insecto Smoke Bombs.
