We use 1020 flats (or trays) to start most of our seeds. They are called 1020 flats because they roughly measure 10″ wide by 20″ long. This is a handy size to carry and can fit a variety of cell sizes. A cell is the part where you plant the seed in the flat. A typical 1020 flat that we use holds 72 cells, but here are more sizes. You can use small pots, too.
We determine the ideal seedling transplant height by taking the 1020 tray cell diameter and multiply that by two. To find the maximum seedling transplant height, multiply the cell diameter by four. Here is a handy guide below to help you determine the maximum seedling transplant height.
|Number of Cells per 1020 Flat||Top Cell Diameter||Maximum Seedling Transplant Height||Ideal Seedling Transplant Height|
It is not a secret that our favorite seed start medium is coco coir, particularly the GP Coco Bricks. It is the best for starting seeds because it inhibits the growth of pathogens that are harmful for the seed. It is a great sustainable grow medium for aquaponics or traditional soil gardening.
When seeds first sprout they are in the vegetative phase of growth and can take extended light hours to help boost growth. We primarily use T5 High Output Fluorescent lights as the power usage is low and they are bright. We try to mimic the Springtime sun by using blue tinted bulbs of the 6500K (daylight) color spectrum. Place the lights as close as possible, providing even lighting coverage and not burning the plants. Rotate the plants at least once a day to make sure the plants do not bend or stretch toward the light. Set the lights on timers for 18 hours of light and 6 hours off.
Who: Dennis McClung
When: May 11th, 2013
Where: The Garden Pool in Mesa, AZ
Length: 44 minutes
This class was recorded live in a classroom setting. To be a part of our classes in person, join our meetup group.
US Extension Office Seed Start Guides
Click on your location from the list below to go to your extension office website. Once you have reached your local extension office office website, search for “planting guide” to find your local planting guide.