Unless you’ve lived under a lake for the last twenty years, you’ve heard about growing indoors and probably even hydroponics. Heck, people under lakes are growing with hydroponics! Yes, better growing is available through modern technology. It allows you to create a carefully-controlled environment for cultivating indoors. You can refine every part of the process, from nutrients to lights, timing schedules, to complex environmental measurements like vapor pressure deficit! Don’t worry, we’ll keep this article a simple intro the best ways to grow indoors.
For the uninitiated, the mere prospect of setting up a garden can be daunting. No doubt you want to see beautiful plants with big green waxy leaves from wall to wall. And you’ll be closer to that goal after reading this article.
Many sources of information seem to complicate the concept of indoor growing and that can prove overwhelming. Luckily for you, we’re going to keep things simple and use the best time proven techniques.
Here’s a brief guide you can follow for growing indoors:
In simple words, hydroponics is an alternative to conventional soil mediums. In simple terms, you can grow plants without using soil.
With hydroponics, the plant is fed nutrients from with the water, and it is usually rooted into growing media, not soil. Basically, you dilute nutrients the plants need in a water and irrigate. Often hydroponics systems are automated with pumps and timers, but not always. Hydroponics does not mean that the plant is kept sitting in water. In fact, air is an important component to keeping a plant’s roots healthy. Overwatering, soggy grow media, or soaking the roots in nutrient solution will deprive the roots of the vital air they need, and often will lead to root rot and a cascade of problems. Another thing to keep in mind, too much nutrients will damage the plant more than not enough. Finally, you’ll probably want to keep track of the pH of the nutrients, so they can absorb the nutrients properly.
We’ll help you choose the right hydroponic system that complements your growth needs. Regardless of the system you select, the media anchors the plants and provides a place for the roots to uptake nutrients and air.
Sometimes ‘grow medium’, grow media is often an inert substrate that allows the plant to anchor itself to stay upright, and the provides a place for the roots to uptake nutrients and air. Common options include Coco Coir, Soil, Rockwool / Stonewool, Perlite, and Hydroton / Clay Pebbles. The key to selecting the right growth media is determining which one will allow your plants to perform best with your system. Some grow media dries out faster than others, for example.
Basic Irrigation Principles
Obviously, plants need to be watered regularly to grow optimally. And to continue on mentioning obvious things, smaller plants use less water and nutrients than larger plants! So choosing the right irrigation system is important, but you must also consider the container size.
For example, a twenty foot tall flowering tree is probably not going to grow out of a three gallon container. And a twenty gallon container is probably overkill for a three foot tall plant! Container size matters.
There are several schools of thought for containers. One is put the plant directly into the final container, another is transplant as they get bigger, and then some hydroponics systems, the container size is negligible because the plant is supported by other means. We recommend transplanting once, into the final containers size. Smaller containers will require more frequent irrigation, than a relatively larger container.
Now that we have that basically out of the way, we can discuss the two basic categories for irrigation systems, run to waste and recycling.
Run to Waste
Run-to-waste (RTW) is the most commonly used irrigation system used by commercial growers. Hand watering, drip irrigation, and nutrient film technique are all suitable for Run to Waste irrigation. The nutrient solution is mixed fresh in a tank, then the plant is watered from a hose connected to a pump. The runoff is often collected in a tray or trough, and it runs to a drain. It is not reused. The main benefit is that the nutrients are delivered to the plant in the exact balance you intend. The biggest detractor, is that it costs more than recycling systems because you’re sending it all down the drain.
Recycling Irrigation Systems
Recycling systems reuse the water from a reservoir. The water is pumped to the plants, and collected in a tray, then it runs back to the reservoir. The nutrients need to be changed at least weekly. The main benefit is you save money on nutrients, and it is better for an automated system where you can’t be there everyday. The biggest problems are that it requires regular pH adjustments, the nutrient balance will be thrown off by each irrigation, pathogens can accumulate in the reservoir and attack the whole crop, and the large tank can increase humidity dramattically if not covered. Drip irrigation, ebb and flow, deep water culture, aeroponics, and nutrient film technique can all be set up as a recycling system.
So now lets go over the water delivery systems.
Systems We Recommend
Growers often focus on lighting and nutrients, the slightly ‘glamorous’ parts of growing indoors, definitely the part that gets the most advertising. So many growers overlook the importance of effective irrigation. We have found the simple systems are the best. Hand watering and drip irrigation are by far the least prone to problems.
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, including paying attention to each individual plant. Monitoring the growth of your plants becomes easier with this method, allowing you to identify any potential problems that emerge.
For one, you’re going to look at each plant because you’re watering each plant individually. This alone gives you a better chance of catching problems as they emerge. Complacency is a risk of automated irrigation.
Drip irrigation is the other popular system we recommend for irrigating your indoor garden. Drip irrigation is best done with a slow drip so that the water evenly spreads throughout the grow media. When the water comes out too fast, it tends to pour down just one side of the media, and the rest stays dry.
The water ‘drips’ into the roots of the plants, and it can be automated with a timer so that only a specific amount of water gets through.
Hand watering is effective and can deliver the results you are looking for, but the manual ‘labor’ can become difficult, and that’s why drip irrigation is so popular. The main drawback with drip irrigation is clogged drippers, but there’s nothing better for saving time.
Systems That We Don’t Recommend
We recommend you steer clear of these irrigation systems, unless you have a specific use case, like aquaponics or lettuce farming. We’ll give an overview of each and touch on the problems we’ve experienced with them.
Ebb & Flow
Ebb & flow is a system that fills an entire tray up with nutrient solution, so that each plant is sitting in a couple 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, no clogged drippers to worry about. 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 plants with low nutrient requirements like lettuce.
Nutrient Film Technique
This is another system ideal for plants that love water, 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 nutrient is running most of the time. Because the roots are exposed, the water must be on most of the time. These two factors, small plant container and bare roots limits 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, and 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. But the chance of catastrophic failure is greatest with this system.
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. If any pump breaks, the plants all suffer. If there is a leak, the tank might drain, and all the plants might die. There are people making monstrous claims about the results from this system, but the amount of energy it uses, and the chances of a catastrophic failure are massive.
Okay! Now we’ve talked about Here’s a brief overview of the most popular types of grow media:
Soil is easily available, convenient to use, and completely natural, making it a preferred grow media for indoor growers. Even though it is not considered a hydroponic grow media, in a strict sense, most growers end up fertilizing the soil throughout the grow. 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. But fast growing plants are hungry, so they’ll need more nutrients almost guaranteed. The aroma and flavor of plants grown in soil is definitely 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.
Soil works with run to waste systems, drip irrigation, and hand watering.
Coco Coir has a great ability to retain moisture. It is more forgiving than hydroton or rockwool. It is the closest to soil of any of the grow media we know. 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. Coco coir is shredded coconut husk that’s composted. It’s important that the coco coir comes from plants that are not near salty bodies of water, like the ocean, or the product will be unsuitable for plants. The neutral pH level of this medium makes it perfect for using 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.
Coco Husk is the less processed version of coco coir. It’s basically chunks of the hull of the coconut. 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 Rockwool, which is a brand name, 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 to allow your plants to thrive. It’s available from several manufacturers like Grodan, in cubes, slabs, pieces, and a loose bail that looks like pillow stuffing. Careful not to breath it in or get it on your skin. It can be very irritating.
Unlike coco coir, rockwool has an alkaline pH value. In recirculating systems you’ll see it move the pH of the nutrient solution upwards. A simple test is to measure the pH of the runoff from the rockwool.
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 of quartz sand, heated until it expands and puffs out.. 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 chunky pieces. We highly recommend the large 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 basically a porous clay pebble with a brown color on the outside. It’s often available in different sizes, from small pebbles to larger ones. Their porousness 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 time a day!
So, there you have it, our brief yet comprehensive guide to growing indoors! We hope the information we provided is helps give you confidence to start growing. At the end of the day, these seemingly simple decisions can have a lasting impact on your success! Grow on.