Basics on Setting Up Hydroponic Grow for Cannabis

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Hydroponic grow setups are often preferred by experienced and commercial growers since it offers a number of advantages over setups that use soil as a growing medium. However, beginners are often intimidated by this growing technique since it can act as a double-edged sword: do it correctly and you can reap impressive yields that are otherwise impossible using soil, do it wrong and you lose your whole crop.

Don’t let this discourage you though. Hydroponics shouldn’t sound like a gamble. Even if you are new to marijuana home growing, you can get good results as long as you understand how hydroponics work and you don’t forget to observe some routine tasks involved in such a setup.

Is hydroponics for you?

Hydroponics is a way of growing plants in nutrient-rich water instead of soil. There are many ways to do this, but the basic idea is to let the plant’s roots grow into a medium that will allow your nutrient solution to flow into. 

Hydroponics is a way to actively “pump” nutrients into your plants. It’s a great way to get fantastic yields but it’s definitely not organic. Nutrients are nothing more than compounds and chemicals, if you get the dosage wrong you could end up harming your plants.

Given this, a hydroponic setup will require a lot more attention and expertise. It’s not as forgiving as soil, you’ll have to constantly monitor everything and deal with a number of other specific issues like diseases spreading quickly, system failures, etc. However, all systems have their own pros and cons and it’s the same for hydroponics, so carefully consider if it is something that would make sense for your growing purposes. 

The advantages of hydroponics

Hydroponics is especially favored by those who need to grow at scale for a number of reasons. Let’s look at the top reasons why:

  • Higher yields – depending on the crop, hydroponic systems can yield twice or even 4 times more than soil
  • Efficient use of water and nutrients – since excess water and nutrients are just recirculated, almost nothing is lost to evaporation or runoff 
  • More plants in a smaller space – without the need for pots full of soil, plants can be put closer together, resulting to greater crop density
  • Can grow whole year round – an indoor hydroponic system is not affected by external climate, you can grow the same number of plants and expect the same yield any time of year 
  • Faster growth – plants grown in a hydroponic setup typically grow 30% to 50% faster 
  • No need for pest control – since hydroponics is usually used exclusively for indoor grows, pests are not usually a problem
  • Give you full control of nutrient flow – the grower has to constantly be on top of fertilizer levels, temperatures and practically every variable involved in growing. Having full control over these things allows the grower to maximize the potential growth and yield of every plant. 

The disadvantages of hydroponics

While these advantages might get you sold on hydroponics, know that it isn’t without any disadvantages. 

  • Requires more attention – a hydroponic setup is a closed system that has to run constantly and consistently. Unlike soil-grown plants that can hold out a few days without supervision, you could lose all of your plants if your hydroponic system fails.  
  • Needs technical knowledge – even without fertilizer, soil will have some nutrients in it which will enable a seed to grow to some extent. A hydroponic system won’t work if not put together correctly. 
  • System failures – since a hydroponic system runs on electricity, it is prone to failure. Your plants can dry out if your system isn’t restored in just a few hours. 
  • Higher initial cost – hydroponic setups require a lot of equipment including grow trays, pumps, airstone, timer, etc.
  • Electricity hazards – water and electricity is a dangerous combination, if your hydroponic setup is installed incorrectly, it can pose a significant hazard. 

Basic parts of a hydroponic setup

There are several types of hydroponics systems but most will be made up with the following parts:

  • Nutrient solution – water that carries the right ratio of nutrients needed by the plants at every stage of growth
  • Growing medium – also called the substrate culture, this holds the plants in place and holds the nutrient and oxygen-rich solution that the roots can absorb. Popular choices are rockwool, coco coir, vermiculite and perlite.
  • Grow tray – a tray that holds the plants and growing medium
  • Reservoir – this is a tank that holds the nutrient-rich water
  • Pump – a hydroponic system may have a submersible pump that circulates the nutrient solution and an air pump with an airstone that aerates the water 
  • Grow lights – this can either be a LED, HID or CFL. See our post on Types of Indoor Grow Lights for Growing Marijuana.

The complexity of the hydroponic setup that you use will depend on the scale of your operation. Simpler setups are typically better for smaller grows and most hydroponic systems will be a variation of these popular types:

Wick system

This is a simple system that’s great for those who want to get their feet wet in hydroponics. In this setup, the nutrient solution is passively delivered into the growing medium by capillary action through the wick. 

Nutrient film

Here, the pump continuously streams a “film” of solution over the roots of the plants which drains into the reservoir and gets recirculated.

Hydroponic setups for cannabis

As cannabis growers, we are concerned more on increasing yields and improving bud quality. Here are some of the hydroponic setups more suitable for this kind of goal: 

Deep water culture (DWC)

This is another system that’s easy to set up, DWC does not require a submersible pump that recirculates the nutrient solution. Instead, the plants are made to float on the water using the grow tray with the roots submerged in the oxygen-rich solution. For this, you can use 5 gallon buckets and a single air pump. Use an inert medium like pebbles to hold your plants in place at the mouth of the bucket.

Pros: 

  • Easy to set up
  • Inexpensive

Cons: 

  • Solution has to be changed periodically, although you can also recirculate your nutrient solution using a pump
  • Temperature regulation can be a problem

Flood & Drain

Also called the Ebb and Flow, this system uses a submersible pump that works on a timer to flow the solution to the grow tray a few times during the day. 

To set this up, your plants should be supported in a pot with a medium like rockwool. Your nutrient reservoir should be able to pump the solution into medium and back into the reservoir.

Pros: 

  • More forgiving since the plants are “aired out” in between flows which can save them if the solution is already out of balance.

Cons:

  • Can be somewhat expensive and moderately complicated to set up 

Drip irrigation

Also called a top feed drip, you need to have a pump that delivers the solution down a network of tubes and emitters to the roots of the plant. Your plants have to be supported in a pot by an inert medium like pebbles or rockwool.  

Pros:

  • Uses less water 

Cons:

  • Can be complicated for beginners to set up
  • Risk of pump failure
  • Emitters can clog up.

Aeroponics

This is the most different in principle from all the hydroponic systems mentioned since it sprays the nutrient solution onto the roots, giving them the highest amount of oxygen of all systems.

Pros:

  • Best yield of all systems since the roots will be highly oxygenated

Cons:

  • Very complicated and expensive

Frequently Asked Questions

What is a hydroponic system?

A hydroponic system does not use soil and instead uses a growing medium that can hold a plant up and allow an oxygenated nutrient-rich solution to get to the roots.

Which is the best type of hydroponic system?

This depends on a grower’s needs but in terms of yield, the best one is aeroponics. It is, however, also the most expensive and involves the biggest risk.

Conclusion

Hydroponic systems offer clear advantages over soil and at times just as simple to set up. Even complicated setups like aeroponics won’t be as difficult as one might expect since there are already kits available that come with complete instructions that even beginners can follow. The only thing that would require a bit of knowledge would be ensuring the correct ratio of nutrients and pH but this is something that can only be learned through application of your research. Mistakes are inevitable even when using soil as medium so there’s really no reason not to give hydroponics a try.   

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