Indoor Seed Starting

Garden Basics
Written By John Miller

Overview:

Creating healthy, vigorous seedlings is so essential when bringing seedlings to life. A properly cared for seedling will translate to the future success of the plat. Here is an overview of how I start a lot of my seeding for my operation, and the products that I use to do so.

Materials:

Temperature: I do not use any heat mats when growing seedlings here in Arizona. In the summer my room temperature for my seed room is 78-80 degrees. Plants grow FAST in this temperature.

Step 1:

I like to start by moistening the seed starting medium in a tub before placing the soil into the cell trays. This ensures that its properly hydrated when seeds come into contact with the mix. You want it wet and firm, but not soggy.

Step 2:

Place grow cells into plastic trays. if you buy the 128 cells from Greenhouse Megastore I recommend cutting the edges off the the sides before putting it on the tray. This can be a bit more labor intensive but you want to make sure the tray lats flat for proper water uptake.

Step 3:

Fill Cells up with seed starting to mix flush with the top.

Step 4:

Sow seeds. I always sow 2 seeds per cell. Thin if desired afterward. I like to break down my seeds into 4 categories when sowing. Check seed packet for sowing depths.

  • surface sown: Surface-sown seeds can be tricky because they are so tiny! Try to sprinkle seeds in the center of the cell.

  • 1/8” deep: I like to place seeds for the depth as if I was surface sowing, right in the middle of the cell. I press the seeds gently into the cell with a sharpie, and then lightly sprinkle a layer of seed starting mix on top.

  • 1/4” deep: Before I place seeds I make an indentation into the soiled cell about 1/4 deep with the back side of my Sharpie. I place seeds in the indentation, then fill the cell back up with soil.

  • 1/2” deep: I hardly ever plant things at this depth, but things like sunflowers like it deeper. I fill the cells up about 1/2 way, and then place seeds in the cells, then cover them up with the soil medium. If you are starting sunflowers, I’ve gotten away with using a potting mix, it saves a bit of money for your operation.

Step 5:

Water in the flats and label! Make sure to put your watering nozzle on the shower function. Make sure the pressure is good, and then quickly go over the seed flats to gently water the seeds.

Step 6:

Sprinkle fine vermiculite over the cells. It doesn’t have to be heavy, but enough to gently dust the tops of the cells. This helps keeps seeds in place (especially surface sown) and lowers mold/algae growth.

Step 7:

Place the Humidity dome on top of the trays. I like to leave them on there until I see that all of the seeds have germinated.

Step 8:

Put the tray under the grow light and watch your babies grow!

Step 9:

Place fans by your seedlings to help ensure proper air circulation. This helps strengthen the stems and reduces potential mold problems.

Step 10:

Check to see if they need any water everyday. Typically I dont start watering seedlings until a day or two after the humidity dome comes off. Fertilize weekly with fish emulsion or fertilizer of choice.

Grow light set up:

This is the setup that works best for me. I do not have to raise and lower the lights using these Mars-hydro lights. Yes, they are on the expensive side but they are SO worth every penny. Pictures below are ONE rack, split in half to make two grow racks. I use the extra shelf to make storage for trays at the bottom. Each unit hold 4 trays.

John Miller
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