Dirt-free gardening in GRODAN GROW-CUBES™ is as easy as following the 4 simple steps below.

GROW-CUBES are a clean, pathogen-free, and lightweight alternative to bulky soil mixes.  Plants grown in GROW-CUBES will also benefit from better nutrient uptake and aeration in the rootzone.  As a result, you will see faster growth and higher yields!


Grow-Cube GuideWhat you need:

  • Seeds, Cuttings and/or small plant
  • 1gallon jug of water
  • Bucket
  • Plant food
  • GRODAN Grow-Cube
  • Plant container(s)
  • Rooting hormone for optional hard cuttings
  • A lemon or a bottle of ‘pH down’ for hard water
Grow-Cube Guide Step 1

Step 1: Preparing the Plant

Small soil plant: gently rinse as much soil off as you can. Do not touch the roots, this may damage the fine active roots. Seeds and Cuttings: start all seeds and cuttings in our plugs. Go to Plant Starters for plug selection and go to Seed under Growing Tips for user guide.

Grow-Cube Guide Step 2

Step 2: Preparing the Food

Hydroponic stores and some garden centers carry a large variety of plant nutrients. You will find organics and in-organics, liquids and powders. They are all designed to dissolve and mix easily with water. Generally they contain a broader variety of nutrient elements than your garden-variety fertilizer. Ask the store clerk for advice on which one is best for your plant.

Plant food mixture

Step 2B

Follow directions on the product label to determine how much nutrient you need per gallon of water.

Step 2B

Measure up the nutrient and add it to a gallon sized container. For hard water, add juice from 1/2 lemon or purchase a ‘pH-down’.

Step 2B

Fill the container with water.

Step 3: Prepare Grow-Cube

Step 3
Pour Grow-Cube into a bucket.
Step 3

Use prepared mixture (from Step 2) to saturate Grow-Cube.

Step 3

Distribute the soaked Grow-Cube into your chosen containers.


Step 4

Step 4: Planting in Grodan

  • Grow-Cube Seedlings: Use a small pot and cover with clear wrap. Do not water before plants begin to root, but mist lightly if necessary.
  • Soil plants: Choose a pot size to suit your plant. See preparing plant before the planting.
  • Transplant to bigger pot only when you have to water very frequently (every 2-4 days).

Note: Grodan Grow-Cube lasts for the life of your plant. When you transplant just add Grodan Grow-Cube to fill the bigger container.

Plant Maintenance and Watering

Step 4Kick the Bucket Method

When you lightly 'kick' the container and it moves, then it is time to water the plant. When the pot feels light, it is time to water. Please see Step 2 for Plant food mixing instructions.

"911 call for water"

In hydroponics the plants can 'tell' you when to water, because they droop before wilting and serious damage occurs. If you come home and the plant is 'lying on the table', water immediately, the plant will recover in a couple of hours.

Note: Plants grown in traditional potting mix rarely recover after 'laying on the table'. Though waiting for this '911 call' is a bit stressful for the plant, in virtually all cases you can still save the hydroponic plant.

Experiment with a plant or two following the instructions in our user guide above . Once you are more familiar with hydroponics you may want employ one of the many self-watering systems that are available in the hydroponic stores.

Some ways to keep your plants healthy and happy are:

  • Locate plants for the correct amount of sunlight. Keep in mind that lunch-time sun light is strong, particularly coming through the window; plants located near windows may burn under such conditions
  • Setup a routine maintenance schedule. Here are some maintenance points to include in your routine:
  • Remove dead leaves and flowers
  • Water regularly, see maintenance and watering
  • Check for bugs and treat before infestation takes control of your plant
  • Check out our guide to Ebb and Flow Bucket Systems
  • Also check out our Ebb and Flow Bucket System comparison video