Updated January 20, 2022

Hydroponic farming is a gardening technique that grows plants using a nutrient solution medium rather than soil. Sometimes, the roots will hang directly into a liquid mixture of water and dissolved nutrients, but in other cases, the plants will grow in some sort of inert substrate growing medium.

There are plenty of pros to starting your own hydroponic garden. It can be as big (or as small) as you want it to be, works pretty much anywhere, and often grows plants faster than traditional gardens.

More often than not, hydroponic plants are more budget-friendly, low maintenance, and versatile thanks to vertical designs and space-saving options. Even better, hydroponic systems typically require less water than in-ground farming and keep your plants safe from many types of diseases and pests.

Should You Build or Buy Your Hydroponic System?

The difference between building or buying your own hydroponics systems will often come down to cost. While it may be more expensive to buy a system that’s essentially ready to use right out of the box, the convenience may be well worth it. On the flip side, building your own system will usually cost less.

If you want to buy a hydroponic garden, there are plenty of trendy systems to choose from that are incredibly user-friendly even for those without a green thumb.

Pre-made hydroponics systems come in different sizes and can be self-watering, self-fertilizing, and most only require seedlings, an outdoor spot that gets at least six hours of direct sunlight per day (or an indoor area with grow lamps), power access, and water access.

Once a week, you’ll add water and nutrients, test and adjust the pH, and that’s it. There are also systems that are built especially for the indoors, like Rise Garden, a modular hydroponics system with built-in LED lights.

How to Start a Hydroponic Garden

Plants really just need water, sunlight, carbon dioxide, and nutrients in order to grow; but hydroponics supplies the plant with those nutrients directly, instead of forcing it to seek them out in the soil. This results in happy plants that grow larger in a shorter timeframe (you’re making it easier for the roots to get the nutrients they need in order to grow).

Since there are multiple different types of hydroponic systems, you’ll have to determine which one works best for you depending on your skill level, budget, and your growing environment. Wicking systems and deep water culture systems make up two of the best options for beginners, since they are low maintenance and often less costly than more advanced systems.

Wicking System

A wicking system is the most basic type of hydroponic system when it comes to DIY, and it works by pumping nutrient solution from the reservoir up the growing tray with the plant roots by way of a wick (something like a rope or piece of felt).

At its core, a basic hydroponics wicking system will have a grow tray to hold the plants, a liquid mix of both macro and micronutrients, a reservoir to hold the water and nutrient mix, a submersible pump to move the nutrients from the reservoir to the growth tray, an air pump to provide the roots with oxygen, and a growing medium such as coconut coir, perlite, or even pebbles. This system is better for plants with low water or nutrient requirements. 

Deep Water Culture System

Another basic system is the deep water culture system, which works by placing plants in net pots that are held above water using a floating platform, with the plant roots suspended freely directly into the nutrient solution (which is kept oxygenated using an air pump, airline, and airstone). This system is recirculating, so it saves water, though it isn’t suitable for larger plants or plants with a long growing period.

Growing Hydroponic Plants From Seed or Starters

Many growers choose to grow their plants from seeds to avoid any damage or trauma that may come from transplanting plants as seedlings. Plus, germinating seeds in soil and then transplanting them into a hydroponic system may add unwanted dirt to the system.

Adding seeds to your hydroponic system also means lessening the chance of introduced diseases or pests from the store. Vegetable starters that have already been seeded and germinated will help you skip a step and shorten the time between planting and harvesting.

Treehugger Tip

When choosing seeds for your hydroponic garden, consider factors like the amount of overall space the plants will need to grow, the amount of space required between each plant, their eventual heights, how long it takes them to reach maturity, and what growing conditions they’ll need.

Hydroponic Garden Maintenance

Perhaps the best part about growing plants in a hydroponic garden is that the lack of soil makes it relatively easy to maintain.

Manufactured kits will typically require less frequent maintenance than the more complex gardens, but both will need to be checked regularly for water levels and pH levels, room temperatures (for indoor plants), diseases, and pests, while the system itself will need to be checked for any technical issues with the pumps. 

Light

When growing outdoors using direct sunlight, hydroponic systems require an average of 8-10 hours of light per day.

Indoors, you’ll need to provide light for longer periods of time since the light is artificial. That means at least 14 to 16 hours of bright indoor light every day, followed by 10 to 12 hours of darkness. Use an automatic electric timer so you don’t accidentally leave your plants with too much or too little light, which can affect growth rates.

Many gardeners use metal halide artificial lights, but there are also options like LEDs and fluorescents to consider.

Mediums and Nutrients

Nitrogen, phosphorus, and potassium are the three main primary nutrients your hydroponic plants will need to stay healthy. Secondary and micronutrients may also include carbon, hydrogen, magnesium, calcium, zinc, nickel, or iron. Premade mixtures are available to purchase at hydroponic stores or local garden centers to make it easy for beginners.

Hydroponic mediums can consist of rockwool, clay rocks, coconut fiber, perlite, sand, or vermiculite. The important part is that you’re using a medium that won’t break down too quickly so that they will continue to support the plants and won’t get too soggy that the roots will suffocate from a lack of oxygen.

Treehugger Tip

Keep in mind that using a substrate or medium may reduce the amount of nutrients received by your plants.

In a 2020 study on hydroponic tomatoes, researchers found that the substrate retained 5% of incoming calcium, 6% of nitrogen, and 7% of phosphorus. Additionally, an average of 51% of nutrients were drained with the solution mixture.

Water

Unlike traditional gardening where the water absorbs from the top of the soil down to the roots underneath, hydroponic plant roots get their water needs directly through the hydroponic pumping system.

You’ll still have to change out the water to refill it as the plants continue to absorb the nutrient solution. A good rule of thumb is to drain and fully change the solution once the volume of your added top-off water equals the tank’s total volume to prevent any accumulation of nutrients and avoid any fungi or bacteria from entering the reservoir; on average, every two weeks.

It is also important to monitor the water’s pH level, which you’ll want to keep between 5.5 and 6.5 in most cases.

Temperature and Humidity

Again, temperature and humidity will depend on the outside influence and the types of plants used. For fall plants, aim for consistent temperatures between 50 and 70 degrees Fahrenheit, and for spring plants, 60 to 80 degrees Fahrenheit. The ideal humidity for most non-tropical plants will vary between 50% to 60%.

During particularly warm summer months, growers may benefit from cooling the liquid nutrient solution to boost yield. 

How to Store and Preserve Hydroponic Plants

Commercial hydroponic gardens tend to harvest plants with the roots attached in order to lengthen the storage life, but home gardeners may want to remove smaller portions of the plants at a time (such as a few leaves of lettuce) and allow the remaining part of the plant to continue growing. They can then be stored, dried, and preserved the same way as plants grown in a traditional garden.

For larger harvests with the roots still attached, like herbs, you can place them in a shallow glass of water in your refrigerator to keep them fresh longer.

Frequently Asked Questions

• Is it hard to start a hydroponic garden?

  It doesn’t have to be. In fact, hydroponic growing can be so simple that a child can do it. There’s even a good chance you gave it a try when you were a kid. Did you ever put toothpicks in a potato and suspend it in a jar of water? If so, do you remember waiting for the roots to grow into the water and then watching green shoots emerge from the portion above the water? That’s hydroponics!

• What is needed for hydroponic gardening?

  You’ll need a hydroponics system, hydroponic nutrients, an inert hydroponics medium, a light source, time, and plants.

• What are the best plants to grow hydroponically?

  Lightweight plants with smaller, shallow roots work best in hydroponic gardens, such as herbs, lettuces, and other leafy greens like spinach, kale, and chard.

  Larger plants like tomatoes and strawberries are also commonly found in hydroponics gardens, though they will require larger scale, more durable systems.

  Root vegetables won’t work as well, and neither will top-heavy veggies.

• Can you build your own hydroponic system?

  If you are handy, you can definitely design and build your own system. Several sites offer lists of free hydroponics system designs. An advantage to building your own system is that you can customize the design to fit your space and the kinds of plants you want to grow.

• Do hydroponic vegetables taste different?

  The flavor and nutrition of hydroponically grown produce is also said to exceed that of soil-grown crops.