Instructions for the Deep-Root Seedstarting System

With cells 50% larger than standard seed starting kits, the Deep Root Seed Starting Kit encourages robust root growth for seedlings that thrive.

  1. Moisten approximately 6 quarts of soilless germinating mix with 4 cups of lukewarm water until the mix feels slightly damp.
  2. Place the Platform in the Water Reservoir. Be sure the raised rim side of the platform is positioned face up. Moisten the Capillary Mat, then lay it on the platform with the mat extending over the unnotched end. Make sure the extended end of the mat is inside the reservoir. Fill the Reservoir with water.
  3. Place the Deep Root Cell Pack on the Capillary Mat, then fill each cell with the moistened germinating mix. Gently press the mix into each planting cell, adding more if necessary, so the cell is completely filled. To ensure capillary action is established, the mix in the bottom of each cell must make contact with the mat. If it does not, firm the mix until it contacts the mat.
  4. Plant one or more seeds into each cell following the seed packet instructions. Group seeds with similar temperature, moisture and light level needs in the same cell pack.
  5. Water the cells thoroughly from above to settle the soil and to ensure good contact with the mat. Place the Dome Cover on top and place in a warm spot. The cover will keep the mix moist and warm, and help your seeds germinate quickly. Be sure to open the vents or remove the cover as soon as your plants emerge.

Providing Light

Be sure to provide adequate light for young plants. Fluorescent grow lights provide a constant, controllable source of light that is better than winter sunshine. Leave the lights on for 14 to 16 hours a day and keep the bulbs 4" to 8" inches from the seedlings by raising the lights as the plants grow.

If you do not use grow lights, place the Deep-Root Seedstarter in a south or southwest window. Rotate it daily to prevent the plants from leaning toward the light.


After germination, most young plants grow best in cool air temperatures (65 to 70 degrees F). This will help reduce legginess. Good air circulation is also important.


Keep the water reservoir full to keep the capillary mat moist at all times. Check the water level regularly and add water through the notched end of the platform. If the mat dries out, thoroughly moisten it to re-establish the capillary action. If the soil seems too wet, empty the reservoir for a couple of days so the soil can dry out.

To keep roots from growing into the capillary mat, lift the cell pack off the mat
once or twice a week.


To ensure a constant supply of nutrients for your seedlings, a diluted solution of liquid fertilizer may be added to the water reservoir.


Your seedlings should be hardened off slowly before they're planted in the garden. Do this by placing them outside for a few hours each day for 1 to 2 weeks, gradually increasing exposure to sunlight and wind.

Once you have transplanted your seedlings into the garden, you may want to plant a second crop of seeds and place the seedstarter directly outdoors. The seeds will germinate quickly in the springtime sun and can then be transplanted into the garden.

Cleaning and Reusing

Wash all parts of the seedstarter with warm water to remove soil and other debris from surfaces. Soak the capillary mat in a diluted bleach solution and rinse in clean water. (All plastic parts of the seedstarter are top-shelf dishwasher-safe.) Store the unit away from sunlight when not in use.

Last updated: 12/09/2022