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How to Plant Seeds in an Earthbox

By Jenny Harrington ; Updated September 21, 2017

An Earthbox allows you to plant a low-maintenance container garden in little space. The box is self watering, so only requires occasional refills of the water reservoir. Fertilizer is only applied at the time of planting as well, eliminating the guesswork. While transplants grow well in the Earthbox, some plants do not do well if not direct seeded. Planting seeds in the Earthbox is as simple as planting them in a garden bed, but they are much more likely to grow into healthy plants in the controlled conditions of the Earthbox.

Fill the Earthbox with a moist soil-less potting mixture. Smooth the soil so it is even with the top rim of the box.

Pour water into the reservoir tube. Add water until it runs out of the overflow hole in the side of the box.

Make a shallow furrow in the soil for the fertilizer stripe, placing it where required for the type of seeds you are planting (see Resources). Pour two cups of dry, general purpose fertilizer in the furrow then cover with a thin layer of potting mix.

Place the plastic mulch cover on the Earthbox, black side facing up. Cut an X in the cover where each seed will be planted, following the same placement guide used for the fertilizer strip.

Sow two seeds per X to the depth detailed on the seed envelope. Generally, sow seeds to a depth twice their width except for extremely small seeds. Sow these directly on the soil surface then cover with a 1/8-inch layer of potting mix.

Sprinkle each planting hole with water and wait for germination. Germination takes seven to 14 days on average, depending on the type of seed.

Remove the weaker seedling if both seeds in each hole germinate. Remove once the plants have formed their second set of leaves.

Keep the reservoir full of water at all times by adding water to the tube until it begins to come out of the overflow hole. Install the Earthbox trellis system if you are growing plants that need support, such as tomatoes or beans.


Things You Will Need

  • Earthbox kit
  • Potting mix
  • Fertilizer
  • Scissors
  • Trellis system


  • Start seeds in an outdoor Earthbox when outdoor planting is recommended in spring on the seed packets. Wheel the Earthbox inside to start seedlings before the recommended planting date.


  • Do not use water soluble fertilizer, as it will break down in the soil too quickly.
  • Never use a potting soil, only soil-less mixes. Potting soil does not absorb water properly from the reservoir.

About the Author


Jenny Harrington has been a freelance writer since 2006. Her published articles have appeared in various print and online publications. Previously, she owned her own business, selling handmade items online, wholesale and at crafts fairs. Harrington's specialties include small business information, crafting, decorating and gardening.