How To Grow Vegetables Indoors Without Soil

Grow Vegetables Indoors Without Soil

Looking to start a garden indoors but don’t want the messiness of soil? Perhaps you only have a small amount of space where you can grow plants and need to find a way to get the most out of your limited space.

Well look no further than hydroponic gardening as this is the most space efficient gardening method without soil.

Hydroponic gardening is the best method for growing vegetables indoors without soil. Hydroponics is where the plants receive the nutrients they need directly from the water instead of the soil. The hydroponic plants will sit in a growing medium to hold them upright such as pebbles instead of soil. Nutrients, and occasionally oxygen, are added to the water for the plants to grow. Plants still need light to grow so a sunny windowsill or a grow light are needed for indoor hydroponics.

Growing vegetables indoors is a great way to have fresh produce year round regardless of the weather outside.

Let’s cover how to get started growing vegetables indoors without soil. First lets understand what hydroponic gardening even is before we cover how to setup a hydroponic system.

What Is Hydroponic Gardening?

Hydroponic came from the greek words “hydro,” which means water and “ponos,” which means labor. Unlike traditional gardening where plants are grown in soil, hydroponic gardening uses the water-based, soil-less method.

At first, it might seem impossible to have a plant grow without soil. It is even more perplexing when you learn that plants can grow bigger, faster, and stronger in hydroponics compared to soil gardening.

However, hydroponics has been around for quite some time.

Hanging Gardens of Babylon

The hydroponic gardening method dates back to the ancient world, as seen in the Hanging Gardens of Babylon. This method has been further enhanced by technology and man-made nutrients. In fact, through aeroponics, even NASA proved that plants could grow in outer space.

So if plants can grow without soil then why do we even need soil in the first place?

What Plants Receive From Soil

The most common form of farming and growing plants is by using soil. Simply planting a seed or seedling in soil, adding water, and waiting for the plant to grow is how most people grow vegetables.

However, in order to grow plants without soil we need to understand what soil provides plants.

Plants need soil for two main reasons:

  1. To hold the plant upright as it grows taller otherwise the plant would fall
  2. To provide nutrients for the plant to grow primarily Nitrogen, Phosphorous, and Potassium (N, P, K)

So we need to provide plants with nutrients and a way to grow taller without falling over if we do not want to use soil.

This is the core principle of hydroponics as we rely on water to grow plants. However, we still need to add a growing medium and nutrients for the plants to grow.

How Does Hydroponic Gardening Work?

Hydroponics is where the plants grow directly in stationary or flowing water instead of soil. Similar to growing a plant in soil, the plant still needs light, nutrients, and a way to support itself as it grows taller.

Below you can see my lettuce seeds that have germinated into seedlings in a hydroponic setup by using:

  1. A container full of water (small glass jar)
  2. A net cup to hold the growing medium and seeds while letting water touch the roots
  3. A growing medium (hydroton) to hold the plants upright
  4. Light from a LED grow light
germinated hydroponic seeds

Starting a seed into a seedling shows that a hydroponic system provides everything a plant needs to start and grow. This system is very simple as it is just a glass jar full of water that encouraged the seeds to germinated into seedlings.

Lets cover the hydroponic equipment needed to grow vegetables indoors without soil from seed to maturity.

Hydroponic Equipment

You can plant almost any vegetable or fruit in a hydroponic set up. Now, you don’t need to get your hands dirty to harvest the “fruits of the earth.” Here is a list of recommended plants for each of the common hydroponic growing methods.

Hydroponic systems can also be mobile, making it possible for you to move from one place or another in case you want to re-do your home’s decor or feng shui.

Below are the equipment needed for hydroponic gardening in order to start growing vegetables indoors:

  1. Grow light. Sunlight is still the best source of light for the growth of plants. Vegetables, in particular, need a minimum of 6 hours per day of direct sun to propagate. Windowsills are the best areas to germinate seeds and grow your plants. In cases where you can’t meet this requirement, opt to use grow lights.
  2. Substrate or Medium. You can use substrates like coco coir, gravel, peat moss, vermiculite, and perlite in place of soil. Other alternatives include rockwool and expanded clay aggregate also know as hydroton. However, you still need liquefied nutrients in the water as these substrates do not provide any nutrients to the plants.
  3. Water. Try to avoid using chlorine or chemically treated water as these can potentially damage your plants. Ideally you want to use mineral or spring water. However, you can simply use filtered water or reverse osmosis water and add your nutrients to the water.
  4. Micro and macronutrients. Pre-mixed hydroponic nutrients are now readily available in the market that come in liquid bottles. Nutrients also come in dry form where they are typically more cost efficient per weight but require thorough mixing and testing before adding to your hydroponic systems.
  5. pH meter. You need to ensure that your nutrient solution is neutral which typically means in the pH range of 5 to 7. Most plants prefer to have water that is around pH 5.5 to 6 which allows them to absorb the most nutrients possible. If your water is too acidic (ph 0 to 5) or alkaline (ph 8 to 14) then your plants will not absorb all the nutrients they need.
  6. Net pots. These are pots that hold your plant with slits or holes near the bottom to allow the roots to grow. There are simple DIY net pots using plastic cups with holes cut in the bottom which allows the water to flow past the roots.

There are other tools that you can use for your setup such as a water pump or air stone but these 6 items are the fundamental tools that you need to setup any hydroponic system.

Simply put:

Hydroponic gardening = Hydroponic system + nutrients + growing medium + light source + plant

Easiest DIY Methods For Growing Plants Indoor Without Soil

The two easiest DIY hydroponic systems for growing plants indoors without soil are the Kratky Method and the Wick System.

Both of these systems do not require an air pump or water pump so it’s possible to grow plants without electricity. This means it’s very easy to grow plants in windowsills and move them around. Not to mention the cost to setup these systems is lower without the expense of electric pumps.

Kratky Method System

The Kratky system is a great way to get started with hydroponics since it’s the easiest to setup. This method is also known as the Set It and Forget It method as you can literally do just that. The Kratky Method is where plant’s roots have direct contact with the water.

kratky method

How The Kratky Method Works

In the Kratky system, you simply let the plant drink the water which means the water level will decrease over time. As the roots continue to grow down into the water, there will be more of the roots that are exposed to air. This is how the plants get the oxygen they need in the kratky system as opposed to air pumps and air stones.

You can be completely hands off with this growing method as long as your water container is large enough for the plant you are growing.

So if you are growing a tomato plant then a small mason jar will need to be refilled almost daily to get the plant to maturity. However, a small herb plant such as cilantro can grow in a small mason jar from seed to maturity without needing extra water.

Equipment Needed For The Kratky Method

Hydroponics is a DIY friendly way to grow plants. I recommend reusing items laying around the house to keep costs low.

Here are the items needed to setup a Kratky system:

  • Water reservoir (mason jar, bucket, etc)
  • Growing medium
  • Liquefied nutrients
  • pH measurement tools and control kit
  • Seedlings in Net pots
  • Grow light (unless plant is in sunny location)

Setting Up The Kratky Method For Hydroponics

Here are the steps to setup a hydroponic system for the Kratky method.

  1. Fill a net cup with a growing medium such as hydroton
  2. Place seeds or a seedling into the net cup
  3. Create a nutrient solution made from water and plant nutrients
  4. Fill the water container such as a mason jar with the nutrient solution
  5. Place the net cup on top of the water container
  6. Set the finished container in a sunny windowsill or underneath a grow light

Plants that grow hydroponically will be ready for harvest faster than plants grown in soil so be sure to regularly check on your plants to see the progress.

Tips For Growing Vegetables In Kratky Method

Once you properly setup a Kratky hydroponic system, you need to keep the following tips in mind to grow your vegetables to maturity:

  1. Use a water container that can hold a fully grown version of your plant
    • Small plants such as herbs can grow in mason jars
    • Large plants such as tomatoes can grow in 5 gallon buckets
  2. If the water level drops below 1/4 of the container and your plant is not finished growing then add more nutrient water
    • DO NOT fill the water container more than 1/2 to 2/3 to the top otherwise your plant will drown
  3. Add liquefied nutrients to the water to provide food for your plant
    • You can simply add more water if the PPM levels of your nutrient water is high enough
  4. Use a black water container or cover your water container with aluminum foil / paper if algae starts growing

Wick System

The wick system is another very simple system that does not require any electric pumps. The wick system usually has a growing area that is placed above a water reservoir with a wick in between.

wick system hydroponic gardening

How The Wick System Works

The wick system uses wicks, such as cotton rope, to pull the water up from the reservoir through capillary action. The plant’s roots will grow towards the top of the wick and pull up water and nutrients as needed.

The benefit of the wick system is that you can plant multiple plants in the grow tray and have plants at different growth stages. The plants will pull up as much water as they need to grow so mature plants will pull up more than seedlings.

The downside to the wick system is that you are limited to the types of plants you can grow in this system. Plants that consume lots of water such as tomato plants will not do well in a wick system since these plants need more water than can be pulled up by the rope. Capillary action works but does not work very fast.

Plants such as herbs and lettuces do well in this system as they are fast growing and don’t require lots of water.

Equipment Needed For The Wick System

Similar to the Kratky method, most of the materials needed for the wick system can be reused from common household items.

Here are the items needed to setup a Wick system:

  • Water reservoir (mason jar, bucket, etc)
  • Growing medium
  • Liquefied nutrients
  • pH measurement tools and control kit
  • Seedlings in Net pots or growing tray
  • Grow light (unless plant is in sunny location)
  • Cotton or nylon wick

Setting Up The Wick System For Hydroponics

Here are the steps to setup a hydroponic system for the wick system.

  1. Fill a net cup with a growing medium such as hydroton
  2. Place the wick near the center of the growing medium and have the bottom dangling out of the bottom of the net cup
  3. Place seeds or a seedling into the net cup
  4. Create a nutrient solution made from water and plant nutrients
  5. Fill the water container such as a mason jar with the nutrient solution
  6. Place the net cup on top of the water container and ensure the wick reaches the bottom of the water container
  7. Set the finished container in a sunny windowsill or underneath a grow light

Plants that grow hydroponically will be ready for harvest faster than plants grown in soil so be sure to regularly check on your plants to see the progress.

Tips For Growing Vegetables In Wick System

Once you properly setup a wick hydroponic system, you need to keep the following tips in mind to grow your vegetables to maturity:

  1. Use a water container that can hold a fully grown version of your plant
    • Small plants such as herbs can grow in mason jars
    • Large plants such as tomatoes can grow in 5 gallon buckets
  2. If the water level drops below 1/4 of the container and your plant is not finished growing then add more nutrient water
    • You can fill the water container as high as you want as long as the roots are not touching the water
  3. Add liquefied nutrients to the water to provide food for your plant
    • You can simply add more water if the PPM levels of your nutrient water is high enough
  4. Use a black water container or cover your water container with aluminum foil / paper if algae starts growing

Start Growing Vegetables Indoors Without Soil

Growing plants indoors without soil, also known as hydroponics, is an efficient and effective way to grow vegetables. This will allow you to have grow, harvest, and eat fresh produce year round.

Simply growing vegetables in a windowsill is a cheap and easy water to get started with hydroponics. Not to mention, growing plants without soil is a less messy way to grow and harvest vegetables.

Starting with hydroponics does not need to be complicated or expensive. There are many different growing methods for hydroponics but the Kratky and Wick Systems are the easiest to do. Each hydroponic system has their pros and cons so you can always expand to other hydroponic systems.

Just get started growing hydroponically indoors regardless of the season so you can get your feet wet with this alternative way of growing vegetables.

Steven

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