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I’ve been starting my seeds indoors for the last six years. When I started, I purchased the 128-cell plug tray kits. These are large trays that each requires a lot of space. If you have multiple trays, you need a decent-sized rack, or racks, to hold them. The more trays and rack shelves you have, the more lights you need. You’ll likely need heat mats as well for seeds that require warmer temperatures for germination.  And naturally, you will need soil for each cell of each tray. This can become quite expensive. It’s also a pain to clean each cell after potting up the plants! And if you didn’t get germination in one or more of the cells, you waste space and soil, which can be very frustrating.

A few years ago, I experimented with a different method using red solo cups and ‘biodegradable’ bags.  This worked okay, but not great. The solo cups required a lot of soil, and the bags did not break down in the soil – I had to remove them by hand at the end of the gardening season.

At this point, I took a moment to reflect on what I was truly trying to achieve. I wanted to start a lot of seeds without consuming too much space in my home. (By then, I had expanded to 5 large racks, each with 5 four-foot-wide shelves, and each shelf with 4 lights!). I also wanted to reduce the amount of soil required to get seedlings started and avoid wasting soil in vessels that didn’t contain a sprout. Simplifying the clean-up process after potting up seedlings was another key goal. And ultimately, of course, I wanted healthy plants.

So, in spring of 2023, I tried another experiment using foil trays, the kind you cook in. I purchased a bulk package from my local wholesale club that had 10 ½” x 13” x 2 ½” deep trays. I used scissors to poke holes in the bottom of half of the trays. I placed those inside another tray that did not have holes in it, enabling proper drainage. I filled the trays with seed starting mix (I particularly like Coast of Maine Sprout Island Blend), used chopsticks to create compressions in each tray to isolate sections for the different varieties of seeds, dropped in seeds, covered and watered them, and waited. I could not have been more pleased with the results. Germination was fantastic. Plants were healthy. Clean-up was a cinch! But then, the question became: what about potting-up?

When the seedlings were ready for their own space, I used the compression marks I had made as a guide for ‘digging up’ each square of starts. Then I gently teased each seedling free and carefully transplanted it into a solo cup. This worked well, but I knew it could be better. At this point, I also purchased cafeteria trays to hold the solo cups, which made it easier to move the plants for watering and for hardening off outside. I could fit 12 cups per tray, and I could fit 4 trays per rack shelf. That’s 36 plants per shelf, which may sound like a lot. But I start hundreds of plants each year. Seed starting was still requiring a lot of space in my house, and even then, I was still using all 5 racks and 100 shop lights (22W, 2200lm, 6500K)!

In the spring of 2024, I decided to ditch the solo cups and try my hand at making soil blocks. I was still using the foil pans to start seeds, but instead of potting them up into solo cups, I purchased a soil blocker kit. I had heard that soil blocks were excellent for plant root health. Instead of hitting the side of the solo cup (or any container) and then growing in circles around the inside of the container, the roots would air prune and not get root-bound. The soil blocker kit I purchased came with 3 different-sized molds. A mini for starting, a medium for potting up young seedlings, and a large for potting up the medium block. I tried to love it. But the mini blocks were very hard to manage. They are prone to drying out, and once they start to dry, they can easily shift inside the container, making it impossible to keep track of each variety. The large blocker was huge! It required a lot of soil, and I couldn’t fit them in my 1020 trays (which I was using to hold both the medium and the large blocks) without wasting space. The medium blocker worked very well. But the blockers are expensive and since I was now doing YouTube videos, I didn’t want viewers to feel they needed to spend a lot of money on tools to easily start their own seeds. So I delved into my next experiment – DIY Soil Blocks!

To do this, I re-used a 4” square nursery plant pot, the kind that holds a plant you purchase from the store. It had flexibility, which is important.  I filled it with very wet soil, packing the soil in tightly. Then, I turned it upside down in one hand and used the other hand to gently squeeze the sides until the ‘soil block’ fell free. It worked perfectly! Then I used my finger to make a small planting hole in the center where I would put one seedling. The size of the DIY blocks was also perfect. I can fit 18 blocks in one 1020 tray.

Today, I use just one rack to hold my seed starts and blocks. The bottom rack holds one heat mat for the foil trays. The rest of the racks hold the 1020 trays with DIY soil blocks. I use the same lights, just fewer, leaving them on 24 hours a day. My 1020 trays time-share rack space in 12-hour shifts. When not on the rack, under the lights, they sit at a nearby table. This has worked perfectly for two seasons, and I don’t have any plans to change my methods. I have very healthy plants to put out in the garden. I have reduced the amount of seed starting mix required, the amount of space required, the electricity I use, and I have saved myself time by only having to clean out a few foil pans and 1020 trays each season. Win, win, win!

I have a seed starting playlist on my YouTube channel if you are interested in seeing my method firsthand.  Remember, you don’t have to spend a lot of money or dedicate a large space to starting seeds indoors for your garden. Happy growing!