During the summer months, heat stress and pest / diseases become a major concern for hydroponic growing in your indoor garden. A lot of growers decide to pack it in for a few months, leaving a gap in the market for your fresh produce if you can keep growing indoors which others experience poor yields due to the heat.
There's a few key products we'd recommend investing on if you want to grow all year round, alongside a few tips for getting the most out of your equipment.
Upgrade to a LED grow light
Choosing the best grow lights for summer heat stress is the first thing we'd do. Old-school HPS technology made it incredibility difficult to grow during the hotter months due to the higher operating temperatures the lamps put out.
Luckily, we're in a position where LED grow lights are affordable and provide you with lower running temperatures, allowing you to kit your grow room out and keep those temperatures down for less power usage, making the switch to led lights even more viable.
You can also run your lights at night, and keep them off during the hotter daytime period. This allow lights to be running during the coolest period of the day, rather than in the hot air, keeping your grow room at the ideal temperature.
Most LED grow lights also offer you the ability to dim your output, giving you maximum temperature control in your grow room and keeping your heat output down. Pick a grow light which will allow you to grow all year round!
Less heat = less heat stress, it's that simple.
If you're finding your grow room temperatures are still too high on your plants canopy, you can look to raise the lights up away from them OR dim down your led grow lights to reduce heat.
Improve your extraction & ventilation systems
If you can extract more air from your grow room, you'll be able to move that hot air and replace it with cool air, keeping grow room temperatures down.
Over-speccing your fan will allow you to put it into 'overdrive' mode, flushing hot air out and replacing it with a cool air flow.
Pair this with a fan speed controller that's thermostatically controlled and your fans will automatically work harder when needed to maintain constant temperatures.
Another way to keep your grow room cool is to use intake air flow from a cooler part of your house / building. Draw air straight from the coolest part of the environment so your fans don't have to do all the work.
Pair this up with nice and straight ducting to minimise any air loss and noise and you're in for a cooler grow room.
If there's no air around your grow room which is suitable to be used, it's better to turn it off completely.
Make sure your exhaust fans are ready for the job; this is a key component if you want complete control of your environment over the summer months
Increase air circulation fans
Microclimates can create hot spots in your grow room, causing certain areas to experience high temperatures with excess heat. Circulation fans allow you to reduce the affects of these areas with their powerful air flow. Proper air circulation also strengthens the stems of your plants, allowing them to be naturally more resilient to pests & diseases.
You can also point oscillating fans at any appliances that get hot, such as lights, ballasts and even chillers for the added bonus of even more cooling.
If you don't have any, point them at the walls of your grow tent to disperse the air circulation evenly, or, go for something like a DiffuseAir.
Increasing CO2 levels
Increasing co2 levels in your grow room naturally increases a plants resilience to any environment stress issues.
With the correct levels of CO2, plants photosynthesise properly, allowing them to cope with higher temperatures between 29-31 degrees.
High temperatures also increase absorption rates, meaning you'll see an increase in plant productivity and fruit production.
For beginners, go for something like Exhale Co2 Bags before moving up to something like an Autopilot co2 generator.
Perfecting your humidity control
As higher temperatures creep in, it's important that you increase your relative humidity levels too.
The hotter temperatures make your plants transpire, causing them to lose moisture through their leaves (transpiration). Keeping humidity levels higher brings your temperatures down by 2-4 degrees on average too, leading to a cool temperature throughout your room.
We also love to use ice cubes in the humidifier to create a instantly cool mist for your plants to thrive in.
Cooling your nutrient solution
There's only so much that fresh air circulation can do, and you need to make sure your nutrient solution is kept free of pathogens and is in the perfect state to feed your plants.
Using a chiller is by far the easiest way to get your nutrient solution to the perfect temperature for summer growing. A chiller acts as a refrigerator for your solution, keeping it at a set temperature. This keeps pathogens at bay and cold nutrients act as a cold beer would for a human; it refreshes them and keeps them nice and cool.
You may also notice that your pH & EC fluctuates more in the summer due to the heat making your plants use more nutrients, so keep an eye on this to avoid overfeeding harsh nutrients (just add more water if the EC is too high).
Another miracle product in your grow room is Vitalink Chill. Vitalink chill should be used just as the warm weather appears to be appearing, allowing your plants to build up a resistance to the heat and letting them thrive in conditions up to 40 degrees!
You WILL need a chiller / need to use Vitalink Chill during the warmer months if you plan on smashing your yields, all year round.
Another that you need to sneak into your summer regime is Silver Bullet. Silver Bullet is there to tackle the bacteria which can build up in nutrient solutions / systems during the hotter months. The heart makes your nutrient solution a breeding-ground for harmful bacteria and pathogens such as pythium (commonly known as root rot).
Once your plants are infected, it's very hard to save them.
Silver Bullet kills 99.9% of these pathogens and lasts in your tank up to 5 weeks, meaning you'll see a fantastic level of protection, even after its initial use.
It's also amazing for general system cleanliness as it breaks down and removes all biofilms from your system.
Icetube pipe is another must have for system users, as the white reflective lining of the pipe can reduce nutrient solution temperatures by 4-6 degrees, reducing the chance of root rot even further.
Other useful additives
Silicon is a must for your grow room during the hotter months. Silicon aids your plants in creating thicker stems, allowing them to lock down the water that's inside of them and pushing their ability to cope with higher temperatures further. Some of our favourites are Nano 10⁻⁹ Nutrients Root+ & 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 and temperature control through the hot summer months.
Pests & disease prevention
During the summer heat, pets and disease thrives, and if left untreated, it can wreak havoc in your grow room. We've already spoken about products such as Silver Bullet which can help to keep your root zone free of root rot, but what else can be done?
There's two steps to pest control, and if the first is done correctly, the second will never come into play.
The first way is prevention, the second is the treatment.
The best ways to protect your plants against pests and maintaining the perfect environment, even during the heat; this involves strengthening plants up as best you can.
Alongside adding silicon into your feeding schedule as we mentioned earlier, you can also foliar feeds to increase your plants natural resistance to heat through the vegetative stage and flowering stage of your plants cycle.
We recommend using something like BioGreen garlic, as this can be used to treat and prevent pests (such as thrips and spidermites) and mildew. Use it at a rate of 1ml per litre of nutrient solution to build up your plants resistance, and then at 50ml per litre when used as a foliar spray. When used throughout your cycle, it provides excellent resistance to heat and the overall temperature in your grow room.
If as a last resort you need to clear out an infestation from your grow room, you can use smoke bombs to flush out your grow space.