A Simple Guide To Hydroponic Plant Spacing

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Plant spacing is an important aspect of planning your hydroponic garden. Hydroponic plant spacing is different than traditional soil gardens. It’s important to give your plants enough space to grow while efficiently using all of the space you have.

Hydroponics allows for a little more flexibility when it comes to planting spacing. Here’s what you need to know to determine the correct spacing for your hydroponic plants.

Plants Need Two Types Of Space

Plants need energy to grow and produce. They typically receive this energy from the soil and the sun.  In a garden, plants are competing with each other for these resources to create that energy. They need to have plenty of both root space and vegetative space.

Simple guide to hydroponic plant spacing

A plant’s root system will grow deep and wide, collecting as much nutrients and water as possible. The plant’s vegetation will also fan out, growing long branches with many leaves to catch as much sunlight as possible. The larger the plant the more energy it can produce, which means a larger harvest in both fruit size and abundance.

How Hydroponic Plant Spacing Is Different Than Dirt

One of the many advantages to hydroponics is that you can grow more in a smaller area as compared to traditional dirt gardens. Hydroponic plant spacing can be closer together.

Root Spacing in Hydroponics

You don’t have to be as concerned with root spacing in your hydroponic garden as compared with soil garden. Since oxygen, water and nutrients are all delivered directly to the plant’s root system it doesn’t need to go looking for it. There’s no competition for resources, so the plant’s root systems take up less space and will intertwine, growing together without causing any issues with the plant’s health.

Vegetative Spacing In Hydroponic

With hydroponics, you do still have to be concerned about vegetative spacing. Since plants don’t need to put as much energy into expanding its root system they will, in turn, spend that energy on its vegetation to increase the amount of light it receives. When spacing your hydroponic plants picture how big you would like your plant to get around and space them out accordingly.

3 Things That Can Affect Hydroponic Plant Spacing

Since there are several variables, the amount of space you should place between you hydroponic plants can vary, it’s definitely not an exact science. It going to depend on the type of plant you’re growing, your pruning and if you plan on training the plant.

The Type of Plants You’re Growing

Leafy greens typically have a shallow root system that doesn’t reach out past about 6 inches. They can also be grown pretty close together within 6-8 inches for bibb lettuce varieties.


Hydroponic lettuce starting to grow

Turns into this.

Hydroponic lettuce ready for harvest.

Larger plants can have a root system a little over a foot wide and several feet long. With proper pruning tomato plants grow well with 10- 12 inches of space.

How Much You Prune Your Hydroponic Plants

Vegetation does not grow well when overlapping each other. One plant will end up blocking the light to the other plant, causing it to be stunted in that area.

Pruning allows you to control the growth of your hydroponic plant but also promotes growth. When you cut a branch it will stop growing out and instead create shoots of that branch. Pruning not only stops your plants from overlapping but can also increase your yields.

You can also harvest your lettuce using the cut and come again method to extend your growing season and increase the amount harvested per plant.

Plant Training

Plants that grow large can also be trained to grow in a desired direction, decreasing the amount of space needed between plants. Typically plants are trained to grow vertically decreasing the space needed between the plants. Sucker leaves are removed and branches cut, promoting vertical growth.

Large plants can also be grown horizontally by slowly laying the plant over as is grows. This will cause the branches to grow vertically and act like top shoots.


Your hydroponic plant spacing is really dependant on how you want your garden, which is one of the many reasons hydroponics is so awesome. You can let your plants grow big or manipulate them to grow in a small space. The ability to customize allows you to create a hydroponic garden that bests fits your grow area.

2 Answers

  1. Patrick Foster
    October 18, 2019 at 12:31 am

    Great article Michael. What size net pot should I use for growing romaine lettuce, tomatoes, cuvumber and bell peppers in a dwc raft (11/2″ polystyrene) hydroponic system?

    1. NoSoilSolutions
      October 18, 2019 at 8:22 am

      Hey Patrick!

      Typically the large the plant, the larger the net pot you should use. The wider and deeper net pots help keep large/tall plants from tipping. I typically use 2-3 in. net pots for lettuce. Cucumbers are usually fine in 3 in. net pots with them vining.

      With the larger pepper and tomato plants, any net pot will work with the type of hydroponic system you’re using.The main concern will be support for the weight of the top of the plant which is going to do all the work of holding up the plant.These plants will get heavy so make sure they are balanced out on your raft. Make sure to share some pictures when you get it going!

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