Outdoor Hydroponics | Pros & Cons + 5 Critical Success Tips

Hydroponic gardening is an interesting and profitable hobby or even career for countless growers around the world.

But, did you know that these water-based gardens are not always indoors and that hydroponics can be grown outside?

Outdoor hydroponics is equally as possible as indoor hydroponics. The major difference between the two is that outdoor hydroponics requires fewer components such as lights, air conditions, and dehumidifiers and that only a few of the hydroponic techniques used indoors are possible outdoors.

Outdoor Hydroponics Pros & Cons

Pros

Cons

  • Works where traditional and indoor growing isn’t possible
  • Utilizes the power of nature, especially the sun and wind
  • Can be less expensive to set up and operate
  • Require fewer electrical components, such as AC units, extra timers, and dehumidifiers
  • Plants are pollinated naturally rather than by hand
  • Sunlight is the most powerful and healthy light for plants
  • Exposure to wind and rain can upset the system
  • More frequent adjustments are necessary
  • Evaporation occurs at higher rates
  • Requires closer monitoring
  • Less control over entire system
  • Pests may be more of an issue
  • Not as many hydroponic methods work as for indoor operations

5 Tips for Maximum Success With Outdoor Hydroponics

Growing plants outdoors in a hydroponic system is a bit different than indoor hydroponics. The following tips will help you achieve better performance and maximize yields.

1. Utilize Sunlight

There is no lighting system that comes close to comparing with the energy that is provided by pure sunlight.

Placing your outdoor hydroponics system in direct sunlight, especially southward facing (as they will be exposed to longer periods of sunlight), results in the best possible plant growth.

At any rate, regardless of which way your system faces, using sunlight for your system, rather than outdoor grow-lights, saves money, requires zero maintenance, and is just flat-out superior to any other type of lighting.

2. Cool Your Water

Just as important as placing your plants in sunlight is positioning your water reservoir(s) in the shade. Shade is the most natural and easiest way to keep your water cool, otherwise, you’ll need to regularly add cool water to your tanks.

Additionally, you can utilize technology to help cool the water in your system. One of the best such devices to use is cooling coils (or a chiller like this).

Submerging cooling coils into your reservoirs is an excellent method for cooling water, albeit one that costs a bit more than utilizing shade.

3. Optimize Airflow

Aside from sunlight, and water, natural airflow is one of the biggest benefits of outdoor hydroponics (as it helps stimulate overall growth, including root development).

That said, your plants won’t benefit from the breeze if they are positioned too close to walls, fences, or trees and tall shrubs.

A couple of more easy ways to increase airflow are the correct spatial distance between each plant as well as placing them where they will receive morning sun and therefore benefit from the dew and an early morning breeze.

4. Practice Pest Control

Outside, your plants are exposed to a wide variety of pests that they wouldn’t face indoors. Being prepared and taking preventive measures is your best bet to stave off pest-based infestations. 

If you’re going for an organic approach to gardening, Natural pest control methods are quite effective, such as cedar mulch on the ground, spraying plants with white vinegar and lemon juice, as well as sprinkling their leaves with cinnamon.

5. Use The Best Type of Hydroponic System

Depending on the type and amount of plants you plan to grow, environmental factors such as weather patterns, surrounding plant and animal life, as well as your climate zone, the best type of hydroponic system to use outdoors varies.

Hence, ensure you install the right one by performing in-depth research and speaking to experts before getting started.

Ebb and flow, top feed, and aeroponic systems are typically the most successful outdoors.

This is due to the fact that controlling excess water is nearly impossible outside, so deep water culture and other methods of hydroponics where plants’ roots are constantly submerged in water are best avoided.

Indoor vs. Outdoor Hydroponics 

The indoor vs. outdoor hydroponics debate tends to be a heated one with veteran growers passionately supporting both sides of the argument. 

But, what exactly are the most significant differences between the two?

Let’s have a look below:

Indoor Hydroponics:

  • Allow you more control over the entire system and growing cycles
  • Work well with every type of hydroponic growing method
  • Are easy to install, operate, and clean
  • Are easier to monitor and balance pH, EC, and nutrient levels
  • Create less evaporation
  • Requires less monitoring and adjusting

Outdoor Hydroponics:

  • Utilize nature and provide plants with a semi-organic environment
  • Don’t need expensive lights or fans
  • Don’t require manual pollination of most crops
  • Work with less timers (for example, there are no lights or fans to turn on and off)
  • Don’t work with all types of hydroponic growing methods
  • Creates higher levels of evaporation
  • Needs closer monitoring and adjusting during hot temperatures

What Hydroponic System Works Best Outdoors?

Three types of hydroponic growing systems are best suited for outdoor operations; ebb and flow, top feed, and aeroponics.

Deep water culture and other versions of hydroponics are less successful outdoors due to the unpredictable nature of the weather.

Hydroponic systems that revolve around keeping plants’ roots permanently submerged in water are much more complicated to use outdoors.

When it rains, and extra water is introduced to the system, everything is thrown out of whack including pH, EC, and nutrient levels in the reservoirs.

Benefits of Outdoor Hydroponics 

Outdoor and indoor hydroponics have several significant differences (as we discussed above), and with those differences come various benefits.

Some of the major benefits of outdoor hydroponics include:

  • Free light. Not only is the lighting free, outside, but it is also completely organic and much healthier than the man-made lights utilized by indoor hydroponic systems.
  • Natural environment. Outdoor hydroponics exposes plants to a more natural environment than indoor systems, regardless they aren’t growing in soil, the temperatures and growing seasons, in general, are organic.\
  • Automatic pollination. Unlike indoor systems that sometimes require manual pollination, plants growing outdoors are pollinated by nature (bees, birds, wind, and other plants).
  • Less power consumption. Outdoor hydroponic systems are capable of operating without fans or expensive lights, which means less electricity and a lower power bill for you.
  • More space. Outdoors, the sky’s the limit (literally), while indoors, the ceiling or light ballasts are the limits of space that plants have to grow.

Drawbacks to Outdoor Hydroponics

Outdoor hydroponics, despite its many advantages, also has a few significant disadvantages.

A few of the main drawbacks to outdoor hydroponics are:

  • Less control of the environment. Factors such as wind, rain, and heat are not as controllable outdoors as they are with indoor systems.
  • Possibly more expensive. Outdoor hydroponics, depending on the sort of system, including the size, may require more equipment than indoor systems, which means more expenses.
  • Wear and tear. Constant exposure to the wind, rain, and heat causes systems to wear out and break down sooner than indoor systems.
  • More pests to deal with. Outdoor systems are far more prone to pests and the damage they inflict.

Does Rain Affect Outdoor Hydroponics?

The main effect of rain on hydroponics located outdoors is fairly straightforward; it alters water, pH, EC, and nutrient levels.

It also changes the temperature of the water in the reservoir as well as the core temperature of plants and their root systems.

Even more, depending on the severity of the rainfall, your plants can bend or break. Their buds/fruits can also be damaged or killed.

If you operate hydroponics outdoors, make sure to keep an eye on weather reports at all times and be quick to take action and support and cover your plants as needed.

Which Plants Grow Best in an Outdoor Hydroponic Garden?

Just about anything that already grows well outdoors is technically able to grow in an outdoor hydroponic system. Light-weight plants with small roots are generally considered the best. 

Among the plants that grow best in outdoor hydroponic gardens are:

  • Greens (lettuce, spinach, micro-greens, and more)
  • Tomatoes
  • Berries (mainly strawberries)
  • Aloe Vera
  • Cucumbers
  • Beans (multiple species)
  • Grapes
  • Watermelon (with proper support)
  • Chives
  • Daffodils

How To Be Successful With Outdoor Hydroponics in Hot Weather 

Below are five more tips to help you successfully grow hydroponic crops even in hot weather:

1. Utilize Shade

Growing hydroponics outdoors revolves around proper usage of shade as well as sunlight. While your plants need plenty of sun, they also need a bit of shade (especially in the heat).

Even more importantly, the water reservoir/tank needs shade in order to regulate the temperature of the water. 

If your system lacks shade, consider installing a shade cloth (these come highly recommended) that you can implement and remove as needed or even a hydroponic water chiller to regulate the water temperature.

This will help keep your water temps where they need to be as well as keep EC levels stable.

2. Help Plants Adjust to Heat

There are more ways than simply applying shade covers to your system, and topping off water reservoirs with cool water to help your plants adjust to extreme heat.

Perhaps the most successful method is adding a bit of humic acid to the reservoir when you mix in nutrients.

Humic acid helps plants adjust to heat by strengthening roots and stems, maximizing water absorption, and overall increasing their heat tolerance. Seaweed extract can also be rather useful for the same reasons.

3. Balance EC Regularly

Monitoring and balancing the electrical conductivity (EC) of your systems’ water and nutrients is another important factor in helping your outdoor hydroponics operations to be successful.

The easiest way to do so is to lower the EC of the water when it’s hot out for long periods of time. One dead give-away that your EC level is too high is slow growth of plants accompanied by browning of the leaves.

To lower EC levels rapidly, simply lower the amount of nutrients you introduce to the system or add extra water. During hot growing seasons outside, keep your water’s EC levels low to medium.

An EC meter like this will help monitor your EC levels.

4. Monitor Oxygen and Nutrients

In addition to EC, oxygen, and nutrients also need extra-close monitoring and balancing when growing hydroponically in the heat.

This can be done by keeping an eye on the temperature of the water in your reservoirs and keeping track of how much hydroponic nutrients you are mixing in.

The ideal water temperature for growing in the heat is approximately 66F to 68F. If water levels climb above 70F, lower them immediately.

Likewise, if by chance water levels drop below 65F (which is not likely to happen in heat, but is possible), raise it back up.

5. Manage Wind Exposure

The slight breeze can be your plants’ best friend during the heat as it helps regulate their temperature and stimulates their overall growth by causing gentle vibrations throughout their leaves, stems, and roots. Indoors, fans are utilized to mimic the wind.

But, too much wind can have the reverse effect. When there is too much hot air it can cause the plant’s temperature to rise as well as heat up the water held in the reservoir.

How Do You Build an Outdoor Hydroponic Garden? 

There is no single method for building an outdoor hydroponic garden. That said, there are a few factors to keep in mind while planning one.

  • Where will you build it (is there enough air, sun, or shade)
  • Where will your water come from (how far will you need to carry or pump it)
  • How large will the system be (how many plants do you want to grow)
  • How much will it cost to run once built
  • How will you clean it

Once you’ve thought about all the above, you can build a simple outdoor hydroponic garden from scratch by following these easy steps:

1. Gather Supplies

You will need:

  • A large container (such as a tote) with a removable lid
  • A 150+ GPH recirculating pump
  • Several 4″ – 5″ wide and 4ft to 5ft long food-grade PVC pipes (with matching end caps)
  • Several feet of PVC tubing, preferably 3/4in wide
  • Net pots
  • Pebbles or clay pellets

You’ll also need a drill, basic hand tools, PVC tape or cement, and either steel pipe plugs or a tap and die set.

2. Set Up PVC Pipes and Net Pots

Create holes big enough for your net pots roughly 10 to 12 inches apart and place the nets inside. Fill the nets with pebbles or clay pellets after you finish the entire build.

3. Connect Pipes for Water Feed

Drill a hole the same size as your PVC tubes into each end of your PVC pipe caps. One hole low on the cap for an outlet and one hole high on the cap for an intake. Before connecting the tubes to the holes, plug in a pipe plug or use a tap and die set to make the connection snug. Follow up with PVC tape or cement to seal it.

4. Set Up Reservoir

Set your water pump in the container and connect the hose to the very top PVC pipe in your system. Make a hole in the lid and use a sealant to prevent evaporation or leaks.

When you fill the reservoir and activate the pump, it will feed water to the top of the system and force it down through each of the connected tubes and pipes effectively watering each grow site.

5. Test and Use Your New Garden

Turn your system on for a test run and fix any issues. Afterward, your new hydroponic garden is ready for use.

Final Thoughts On Hydroponics Outdoors

Outdoor hydroponic gardening, while more than possible, and lucrative, especially in areas where soil-based gardening isn’t really an option, is not always the best choice for hydroponic home gardeners. 

In the very same breath though, sometimes it IS an excellent solution. For example, when you don’t have indoor space, or don’t want to spend enormous amounts of money.

As far as whether or not outdoor hydroponic gardening is right for you, only you can decide. Hopefully, our information-packed guide helps you make that decision.