If you plan on growing vegetables, herbs, or cannabis indoors, chances are you’ll be exploring a hydroponic grow system. Technically, hydroponics is just growing without soil, but it encompasses so much more.
The hydroponics environment includes not only the soilless growing medium and the nutrient solution, but also lighting, temperature, and relative humidity.
When you grow plants indoors, you’ve got to provide all the necessities of life. It’s all about timing and balance.
Let’s break down the basics of an indoor environment for a hydroponic grow system.
Hydroponics 101: What is it?
Hydroponics is “the cultivation of plants in nutrient-enriched water, with or without the mechanical support of an inert medium such as sand or gravel,” as per Encyclopedia Britannica.
Widely used by indoor growers for vegetables, herbs, and cannabis, hydroponic grow systems provide all the necessary components for growth. Growers love them because they provide a level of control over the environment and produce higher yields.
A simplified hydroponics definition is growing plants in a nutrient-rich solution without using soil.
Naturally, growing in soil can produce inconsistent results. So, by removing soil from the equation, growers gain more control over the entire indoor environment.
In hydroponic growing systems, plants root in a sterile growing medium, like clay pellets or Rockwool. Then, their roots are suspended within or sprayed with all the nutrients and water to maximize growth.
But the physical hydroponic setup is just one piece of the puzzle. Plants need light and many other environmental elements to thrive.
1. The Grow Tent: A Controlled Environment
Part of the appeal about growing indoors is the control. Many cultivators go a step further and seal off their indoor growing space for even more control.
The most popular way to do this is with a grow tent or grow closet. Grow tents are standalone frames covered in a sturdy fabric that helps retain heat and humidity and eliminate light penetration (something that can throw off a plant’s growth cycle).
The interior of the grow tent is highly reflective, which not only helps with temperature but also redirects some of the indoor lighting in and around your plants. While most are not hermetically sealed, grow tents still offer substantial protection against microscopic pathogens that may exist elsewhere in the home, garage, or basement.
2. LED Lighting: Recreating a Natural Schedule
If you’ve ever tried to grow a house plant in a dark apartment, you’ll appreciate the need for additional light sources when growing vegetables and cannabis indoors.
Most plants need at least six to eight hours of direct light a day, while cannabis can take upwards of 24 hours at some points. The only way to get this much light is with indoor grow lights.
Installing an LED light in your grow tent aims to replicate and improve upon what’s available from the sun. First, it’s important to recreate a natural schedule to reproduce the seasonal daylight and spectrum changes. Shorter days and warmer-toned light encourage certain plants to fruit.
Second, indoor LED grow lights allow you to cater to the specific needs of your plants. Whether growing tomatoes or flowers, you’ll need to adapt the lights to each species’ individual needs. For example, setting a longer daylight period maximizes vegetative growth, and adjusting to warm red lighting stimulates flower production.
3. Water and Nutrients: The Building Blocks of Growth
Just as important as light, plants also need access to water and nutrients in order to grow. Plants need to have ongoing access to these elements, and in the right ratios, for consistent healthy development. In hydroponic grow systems, water and nutrients are combined into a nutrient solution.
From lettuce or peppers to cannabis, whatever you are growing will thrive with a species-specific nutrient ratio. That means variations on the nitrogen, phosphorus, and potassium (NPK) formula, plus a host of micronutrients like calcium, magnesium, and countless others. The optimal ratio for these nutrients also changes throughout the plant’s life cycle.
If you are growing in soil, any miscalculation with nutrients and water is buffered by the soil itself. But this isn’t the case with a hydroponic grow system, where it’s critical to get the formulas right — and at the right time.
For anyone just getting started, it can be helpful to have a step-by-step guide to nutrients. The HydroGuide App provides precise formulas and schedules that demystify the entire growing process.
4. Relative Humidity and Temperature: Getting the Balance Right
The final important components you’ll need to consider within an indoor growing environment are temperature and relative humidity.
For example, cannabis prefers temperatures between 70 to 78 degrees Fahrenheit during vegetative growth and 68 and 75 degrees Fahrenheit during flowering. It also thrives with slightly lower temperatures at night. If you keep the environment too hot or too cold, the best-case scenario is stunted growth. Worst case, you’ll kill your plants.
Depending on where (and when) you are growing, you may need to install a heater or an air conditioner with an automatic controller that activates when needed. This creates a consistent ambient temperature no matter what’s happening outside the grow tent.
Equally as important as temperature is relative humidity. In fact, without moisture in the air, plants cannot photosynthesize. In our cannabis example, you’ll want to hit 45 to 55 percent humidity during veg and 35 to 45 during flower.
One of the secondary considerations regarding humidity and temperatures is keeping pests and pathogens at bay.
Molds, mildews, and algae all love hot, humid environments. If the relative moisture content of your grow tent goes unchecked, you could create the perfect environment for bud rot, powdery mildew, or another pathogen.
Mastering the Environment With a Hydroponic Grow System
Water, nutrients, lights, temperature, and humidity controls are critical tools for growers perfecting the indoor grow space. The need to control all aspects of the plant’s environment is why hydroponic grow systems are so popular for indoor growing.
Taking on the indoor grow environment can seem daunting in the beginning. But, part of the fun of learning to grow indoors is perfecting the process through ongoing trial and error. Even the most experienced growers are still tweaking their systems and trying new approaches. Once you learn the basics, where will you take it?