By Global Garden
While most people have grown a plant outdoors, people often seek out a guide on indoor growing for beginners. Fortunately, we’re providing just that. You’ll be happy to learn that a lot of the same principles that apply to outdoor growing also apply to indoor growing. These include applying the proper amount of nutrients and using healthy watering practices. With that said, there are some crucial differences.
Modern technology allows you to create a carefully controlled environment for growing indoors. You can refine every part of the process, including nutrients, lights, timing schedules, and complex environmental measurements like vapor pressure deficit. If you’re already overwhelmed, don’t worry. We’ll break these items down below.
In this guide, we’ll cover different types of indoor growing operations, including hydroponics and soil-based systems. We’ll also explain important factors to consider including nutrients, irrigation, lighting, and other environmental factors.
Types of Indoor Growing Systems
There are two types of indoor growing systems: hydroponic and soil-based. We’ll explain each one below.
In simple terms, hydroponics is growing plants in a liquid nutrient solution rather than in soil. Plants are supported by solid media, yet the media doesn’t provide nutrients.
Hydroponic systems range from simple home systems to complex operations that span acres.
There are six main types of hydroponic systems:
- Deep Water Culture
- Drip System
- Ebb and Flow
- Nutrient Film Technique
All of these hydroponic systems supply plants with water, nutrients, and air. However, these systems differ in how they supply these elements.
As you might suspect, plants in soil-based systems are grown in soil. When you think of traditional gardening, you’re thinking of a soil-based system. The soil helps provide nutrients to plants through biological processes.
In indoor systems, growers can use containers filled with soil or plant directly into the native soil.
Grow Room Supplies List
The supplies you need for indoor growing depends on what type of system you are using. Hydroponic systems and soil-based systems require different equipment.
With that said, all grow rooms require the following basic supplies:
- Irrigation equipment
- Growing media/soil
Plants need water to grow. However, what’s not obvious is how to apply water to your plants. There are several systems available for indoor growing.
Run to Waste Irrigation Systems
Commercial growers often use a run to waste (RTW) system.
In RTW irrigation, growers mix nutrient solution in a tank. They then apply this solution to plants. Rather than collecting the runoff, growers allow it to run into a trough or the ground.
The main benefit is the system delivers nutrients to the plants in the exact balance you intend. However, a detractor is that it costs more than recycling systems because you’re sending it all down the drain.
Recycling Irrigation Systems
Recycling irrigation systems reuse the water from a reservoir. The water is pumped to the plants, runoff is collected in a tray and then returned to the reservoir. The nutrients need to be changed at least weekly.
One of the main benefits of this system is that it helps you save money on nutrients. Also, it is better suited for an automated system if you can’t be there every day.
This system does have the potential for some problems. Growers must regularly monitor and adjust pH and nutrients. Also, pathogens can accumulate in the reservoir and attack the whole crop. Finally, the large tank can dramatically increase humidity if it’s left uncovered.
Types of Water Delivery Systems
Growers often focus on lighting and nutrients, the slightly ‘glamorous’ parts of growing indoors. However, many growers overlook the importance of effective irrigation. We have found the simple systems can perform just fine.
Hand watering is the classic way to irrigate plants. Hydroponics does not exclude irrigating by hand. Expert growers understand the many benefits of hand watering their plants. When you’re hand watering, you can examine each plant. By doing so, you can spot early signs of disease and nutrient deficiencies.
As the name suggests, drip irrigation utilizes small drips of water to irrigate. Small plastic lines are filled with water. Tiny holes in the lines slowly drip water, providing controlled irrigation.
Drip irrigation is best done with a slow, steady drip. This allows the water to evenly spread throughout the grow media. When the water comes out too fast, it tends to pour down just one side of the media, leaving most of the media dry.
Growers can automate drip systems with a timer. This is helpful to save time and also to control the amount of water that gets through.
The main drawback is that drip lines sometimes get clogged with buildups up nutrients or salts. A filter can help prevent this.
Advanced Hydroponic Growing Techniques
While hand watering and drip irrigation systems are simple ways to provide water to your plants, there are more advanced systems.
Ebb & Flow
Ebb & flow is a system that fills an entire tray up with nutrient solution. Each plant sits in a couple of inches of nutrient solution. Then it all drains back into a reservoir after a predetermined amount of time. First off, the good thing about this system is it will water every plant in the tray.
However, this system requires more water than any other system, except deep water culture. Due to the bottom-up feeding method, nutrients build up inside the grow media, so flushing becomes a necessity as the plants age.
Finally, you’ll have humidity spikes when the system is running because all the water is on an open tray. However, this system works pretty well with aquaponics and for plants with low nutrient requirements like lettuce.
Nutrient Film Technique
This is another system ideal for plants with small root systems, such as lettuce. Plants are placed in a small container or the stock is held in place in a lid over a trough. The roots grow into a trough where a nutrient solution is running most of the time. Because the roots are exposed, the water must be on most of the time.
The small plant container and bare roots limit this system to small water-loving plants. Did we mention lettuce?
The sheer volume of pieces and variables makes this system risky to use and super technical. You can experiment with aeroponics if you want to take up growing as a hobby, but as a serious grower, you should avoid using it.
Scalability is a major wall with this system. Also, the risk of root rot is massive because the water pump is constantly running heating the water. Let’s not even get into how difficult it is to clean and maintain or even change nutrients.
These systems are usually extremely expensive and produce mediocre results. Plants need a lot of support in this system if they grow over six inches tall. Don’t believe the hype. The aeroponic cloning machines can be useful in cloning some difficult to root strains, but that’s about it.
Deep Water Culture
Deep water culture (DWC) is an interesting system. It shares some of the same problems as aeroponics. There are tank based deep water culture systems, where plants like lettuce, float around on little styrofoam rafts. Then, there are more complex DWC systems where each plant has its own container, like a fancy bucket.
Water is circulated through the system with a pump, and a water chiller is often used to keep the temperatures in an acceptable range. Because the plants are submerged in water almost the whole time, it’s essential to inject air into the nutrient solution using an air pump and a diffuser.
If the water is too warm, the air will not dissolve into the nutrient solution. If it’s too cold, the plants will not grow well.
Serious damage can happen if a pump breaks or if there is a leak. If this happens, the plants will suffer and the plants might die. Some people make monstrous claims about the results from this system. However, it uses a large amount of energy, and the chances of a catastrophic failure are massive.
When you’re starting an indoor grow system, another important element to consider is your growing media.
If you’re using a soil-based system, you will be using soil. Duh.
Fortunately, soil is easily available, convenient to use, and completely natural. Usually, the soil you use for growing contains nutrients, enabling it to provide fast-growing plants the nutrition they need for the first stages of growth. However, soils can also hold nutrients and make them unavailable to plants.
The aroma and flavor of plants grown in soil are different than hydroponically grown plants, but this is a matter of taste. Soil grown plants often take longer to mature and ripen than hydroponically grown plants.
This media works with run to waste systems, drip irrigation, and hand watering.
Coco coir is shredded coconut husk that has been composted. It’s great at retaining moisture, and it’s more forgiving than hydroton or rockwool.
It’s the closest to soil of any of the grow media. Coco coir has certain qualities that modify the availability of nutrients to the plants, so it’s common for growers to use coco specific nutrients to optimize plant growth.
The coco coir must come from plants that are not near salty bodies of water, like the ocean. Excess salts make the product unsuitable for plants. The neutral pH level of this medium makes it perfect for use with a variety of plants. It is often mixed with perlite for better root aeration, and sometimes with organic ingredients like guano, manures, or soils.
Coco Coir is excellent for hand watering, run to waste, and drip irrigation.
This material is the less processed version of coco coir. It’s basically chunks of the coconut hull. Many growers use this instead of perlite to aerate the rootzone. It’s also used alone for plants that naturally grow in trees, like orchids. We recommend using this in conjunction with coco coir for most crops.
Rockwool / Stonewool
Commonly called by the brand name Rockwool, stonewool is basically a rock melted and spun in something that looks like a cotton candy spinner. The final product provides an excellent water to oxygen ratio, which allows your plants to thrive.
It’s available from several manufacturers in cubes, slabs, pieces, and a loose bail that looks like pillow stuffing. Be careful not to breathe it in or get it on your skin, as it can cause irritations.
Unlike coco coir, stonewool has an alkaline pH value. In recirculating systems, you’ll see it move the pH of the nutrient solution upwards. To see how stonewool is affecting pH, measure the pH of the runoff from the system.
Stonewool is compatible with run to waste, hand watering, drip irrigation, and flood-and-drain.
Perlite is another grow media that is best used in conjunction with another media. It works great for orchids, but for the majority of crops, it’s best as an additive. This material is made of quartz sand that is heated until it expands and puffs out. It looks kind of like puffed rice.
Adding it to coco coir, soil, or rockwool will enhance the aeration and draining properties of the media.
Perlite is suitable for growers who find it difficult to get enough air to the root zone. Usually, perlite will make up around a third of your potting mix. Perlite is often available in different size ranges, from pieces slightly larger than sand to large pieces. We highly recommend the larger, chunky perlite.
Used alone, like with orchids, we like to hand water and allow the container to rest in a dish of the nutrient solution. The perlite is excellent at wicking up the nutrient solution. Mixed with other media, perlite works well with hand watering, drip irrigation, and drain to waste.
Hydroton/ Clay Pebbles
A very popular choice among indoor growers, hydroton was once the most popular grow media for hydroponic gardens. Those days have long past since the advent of stonewool and coco coir.
Hydroton is a porous clay pebble. It’s often available in different sizes, from small pebbles to larger ones. This material’s porosity enhances the supply of oxygen to the roots because little bubbles of air are formed on all sides of the pebble.
It’s often important to provide additional support for a plant in hydroton, as the pebbles are rather light and can shift around easily.
Hydroton is great for many different types of hydroponic systems, flood and drain, drip irrigation, and run to waste. Due to the nature of Hydroton not retaining much water, hand watering is usually avoided…unless you want to water the plants several times a day!
When you’re reading about indoor growing for beginners, you might be overwhelmed by lighting. After all, there are a lot of options and terminology!
There are two main types of lights used in indoor growing: light emitting diode (LED) and high intensity discharge (HID). Ceramic metal halide (CMH) and high pressure sodium (HPS) are both types of HID lights.
As you probably know, plants need nutrients to thrive. However, the exact nutrients plants require depends on factors including the plant size, growth stage, and type of plant.
Fortunately, there is a wide range of nutrients available. Some are suited for the vegetative stage of plant growth, while others are best for the flowering and fruiting stages.
Another important factor to consider with nutrients is the pH. If your pH is not in the right range, plants will be unable to take up nutrients.
As mentioned above, one of the best things about growing indoors is that you can control the environment. Some factors to control include temperature, relative humidity, airflow, and carbon dioxide levels.
To control the environment, you can use equipment like a humidifier or dehumidifier, fans, and heaters. Once you get more into growing, you can invest in controllers to help automatically adjust elements of your grow room.
Starting Plants Indoors then Moving Outdoors
One more thing we want to cover is starting plants indoors. Even if you want to grow outdoors, you might want to start your plant indoors.
By starting plants indoors, you can get a jump start on your growing season. When it’s still cold and dark outside, you can provide an indoor area for plants that is warm and bright.
When moving plants outdoors, make sure to harden them off. If you put plants right from a protected, controlled into the outdoors, they will be overly stressed.
About a week before you want to move your plants outside, start taking them outside for an hour each day. Gradually increase the time the plants are outside. This will allow them to adjust to the sunlight, wind, and outdoor temperatures.
We hope the information we provided gives you the confidence needed to start growing. At the end of the day, these seemingly simple decisions can have a lasting impact on your success. Grow on!