I have been soil blocking since the beginning of my flower farming career in 1998. When I learned of seed starting with soil blocking it solved a couple of challenges for me.
I didn’t, and still don’t have a greenhouse. My urban farm’s city location doesn’t offer much hope of ever having one, so this method offered some great options I could build on. First, I saw how I could use trays without drainage holes which was totally liberating from all other methods. Secondly, it could be incredible space savvy.

Soil blocking is not only a viable seed-starting method for farmers, but is a perfect fit for the home gardener. The blocks are easily managed in a small space in a home because it can be self-contained. In the footprint of a tabletop grow light, 12” x 24” you can support 240 seedlings until they go outdoors.
All of the following information is based on my experiences for my seed starting setup situation. I have tweaked the steps to make it possible for me to use an indoor room, 10’x10’, to start and support over 15,000 soil blocked seedlings at a time.

I use stainless steel rolling racks with 3-6 adjustable shelves per rack equipped with grow lights. Each shelf holds 720 mini soil blocks on rigid reusable cafeteria trays. I have 3-4 racks in the room depending on the season. Another bonus is this room is a part of our work building that is already heated and air conditioned, so no additional expenses or concerns over weather events as with a greenhouse.

Because of my unique seed starting needs and space available I was forced to go out of the box on the recommended steps to follow. I’ve learned that it is very possible and viable to strip down the method to bare essentials and produce an amazing quality of transplant and do so indoors in a small space.
Please visit our website for soil-blocking equipment, videos and helpful tips.
Happy seed starting!
Lisa Z
Founder of The Gardener’s Workshop and Flower Farming School Online . Author of Vegetables Love Flowers, Cool Flowers, and The Easy Cut-Flower Garden .
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Becca
Wow I am learning so much from you! Thanks for making home gardening so attainable. I have a question about the lights you use- do you use fluorescent or LED? And what is the type of bulb? Maybe the spectrum? Thanks for all you share!!
Lisa
Hi Becca, I use T-8 or T-12 fluorescent bulbs. Lots of info out there- I have many fixtures that work well so haven’t looked into LED.
Anne Harding
Hi Lisa! Can you put the styrofoam trays carrying the seedlings directly on to the seedling heat mat? I missed the step when they are moved from the small styrofoam tray to the larger tray so I’m not sure when that happens…thank you!
Anne